Laser device

Information

  • Patent Grant
  • 6822228
  • Patent Number
    6,822,228
  • Date Filed
    Thursday, November 1, 2001
    23 years ago
  • Date Issued
    Tuesday, November 23, 2004
    20 years ago
Abstract
A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.
Description




TECHNICAL FIELD




The invention pertains to laser devices, including laser scanning devices and laser desorption spectrometers, as well as other devices.




BACKGROUND OF THE INVENTION




The use of lasers has become increasingly widespread. Lasers can be used for manufacture of products, material analysis, etc. Chemical imaging is one form of material analysis. Chemical imaging using mass spectrometry has attracted increasing interest because of numerous applications for characterizing materials science samples, biological tissues, individual aerosol particles, minerals, forensic evidence, etc. Chemical imaging is often based on secondary ion mass spectrometry (SIMS) by bombarding a surface with atomic primary beams to yield elemental secondary ions from a surface being analyzed. One disadvantage of such techniques includes surface charging that can lead to redeposition of material. Further, for SIMS, chemical imaging usually uses atomic ion primary beams that provide primarily elemental and not molecular chemical information.




Recently, laser desorption (LD) techniques for mass spectrometry have attracted attention because they produce intact molecular ions, avoid surface charging issues, and allow tuning of laser irradiation (wavelength and fluence) to accommodate various sample types. Careful control of laser fluence prevents excessive sputtering that can contaminate adjacent locations of a sample also intended for analysis.




Traditionally, LD microprobe mass spectrometers use scanning techniques that rely on manipulation of a sample target. Alternative LD techniques may accomplish manipulation by moving optical components. In such cases, spatial resolution (minimum controlled displacement of laser energy on the sample target) has been limited to mechanical resolution (minimum controlled displacement per step) of stepper or servo motors used to move the sample target or optical components. Such techniques often encounter problems with reproducible alignment of laser scans with sample targets. Often, such techniques are not easily amenable to analysis under extreme conditions including confined space, high magnetic fields, operation under vacuum, operation under high pressure, operation under hazardous conditions, etc.




SUMMARY OF THE INVENTION




In one aspect of the invention, a laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component. Distance H can be greater than distance J. The laser device can include a laser source manipulation mechanism exhibiting a mechanical resolution of positioning a laser source. The mechanical resolution can be less than a spatial resolution of laser energy at the target position as directed through the optical component. As one example, the target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The laser source can be a virtual source and can be placed in scanning motion by the manipulation mechanism. The laser source can also be linked to a pendulum assisting in alignment of laser energy. Further, spatial resolution can approximately equal the mechanical resolution multiplied by a ratio of distance J to distance H. At least one of distance H and distance J can be altered, modifying the spatial resolution. The manipulation mechanism can include a Peaucellier linkage also assisting in laser energy alignment. At least one desorbed energy detection cell can be provided such that the laser device is comprised by a laser desorption spectrometer. The laser device can instead be comprised by other systems.




In another aspect of the invention, a laser device can include an optical component having a vertical index and a lateral index that intersect at an origin, a laser energy source aimed at the origin, and a laser source manipulation mechanism. The manipulation mechanism can link vertical and lateral laser source motion to the respective vertical and lateral indices and auto align laser aim through the origin during laser source motion. As an example, at least one of the lateral index and vertical index can comprise a line. Lateral laser source motion can be physically linked to the lateral index. Vertical laser source motion can be physically linked to the vertical index. The manipulation mechanism can provide a center of lateral pivot for the laser source approximately coincident with the lateral index and a center of vertical pivot for the laser source approximately coincident with the vertical index.




In a further aspect of the invention, a laser device can include a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component. The laser device can include a laser source manipulation mechanism having a mechanical index. The mechanical index can provide a pivot point for laser source lateral motion and a reference point for laser source vertical motion. Lateral displacement of the laser source can produce a related, predictable lateral displacement of laser energy at the target position as directed through the optical component. Vertical displacement of the mechanical index can produce a related, predictable vertical displacement of laser energy at the target position as directed through the optical component. As an example, the optical component can comprise a lens and the mechanical index can track a curved surface of the lens during vertical motion.




In a still further aspect of the invention, a laser device includes an optical component, a laser energy source separated from the optical component, and a laser source manipulation mechanism comprising a Peaucellier linkage. The manipulation mechanism aims the laser source through the optical component. As an example, the Peaucellier linkage can include a mechanical index, the mechanical index providing a pivot point for laser source lateral motion and a reference point for laser source vertical motion.




In another aspect of the invention, a laser device includes a target position located within an adverse environment, an optical component separated from the target position, a laser energy source located outside the adverse environment, and a laser source manipulation mechanism comprising electro-mechanical parts all of which are located outside the adverse environment. The manipulation mechanism can aim the laser source through the optical component at the target position. As one example, the laser source can be separated from the optical component by at least about 1.3 meters (4 feet). The adverse environment can include at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone.











BRIEF DESCRIPTION OF THE DRAWINGS




Preferred embodiments of the invention are described below with reference to the following accompanying drawings.





FIG. 1

is a side view of selected features of a laser device according to one aspect of the invention.





FIG. 2

is a diagram of auto aligned laser energy through a lateral index.





FIGS. 3A

to


3


C are respective side, front, and top views of selected features of a laser device according to another aspect of the invention.





FIG. 4

is a diagram of auto aligned laser energy through the origin of a binary index.





FIG. 5

is a cross sectional view of a virtual source used with the laser device of

FIGS. 3A

to


3


C.





FIG. 6

is a side view of selected components of a laser device used as a laser desorption mass spectrometer.





FIG. 7

is a top view of the selected components shown in FIG.


6


.





FIG. 8

is a scanning electron microscope image of an aluminum foil target processed in the laser device of

FIGS. 6-7

.





FIG. 9

is a scanning electron microscope image of a printed circuit board analyzed in the laser device of

FIGS. 6-7

.





FIG. 10

is a chart displaying spectral results from analyzing the printed circuit board of FIG.


9


.











DETAILED DESCRIPTION OF THE INVENTION




As may be perceived from the examples and exemplary embodiments described herein, some aspects of the present invention were derived from development of a laser desorption mass spectrometer. However, it will be apparent to those of ordinary skill that the several aspects of the invention can be applied in a variety of ways. For example, the aspects of the invention can also be used in fabrication of microelectronic, micromechanical, and similar devices, in recycling of precious materials by selective desorption, in spatial control of optically induced chemical processes, etc. A variety of highly refined laser desorption techniques or applications are possible, including applications in the semiconductor industry for fabrication and quality control. For example, a laser desorption device as described herein could verify the location and composition of features on manufactured devices in context with a desired reference point. In each of the described applications, the aspects of the invention may be incorporated into a robotic system.




According to one aspect of the invention, a laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. The laser device also includes a laser source manipulation mechanism exhibiting a mechanical resolution of positioning the laser source. The mechanical resolution can be less than a spatial resolution of laser energy at the target position as directed through the optical component. In the context of this document, the term “laser energy” is defined to include “laser beam” and/or “maser beam” as known to those skilled in the art as well as other forms of “laser energy” that may be consistent with the various aspects of the invention described herein.





FIG. 1

provides one of several possible examples of the subject laser device and can be used to illustrate the concept of mechanical resolution being less than spatial resolution. A laser device


10


of

FIG. 1

includes a lens


12


positioned to focus laser energy


8


at a target position


14


. Although lens


12


is shown in

FIG. 1

, other optical components can be substituted for lens


12


in keeping with a particular application for the invention selected from among the various possibilities. Any optical component suitable according to the knowledge of those skilled in the art can be used, including multi-element optics. A virtual source


18


provides laser energy in FIG.


1


. Using a virtual source can yield particular advantages described in further detail herein, however, any laser energy source can be used that is suitable to a particular application according to the knowledge of those skilled in the art. Target position


14


is shown separated from lens


12


by a distance J. Lens


12


is, in turn, shown separated from virtual source


18


by a distance H.




Multiplication of the resolving power of laser device


10


can be accomplished when distance H is greater than distance J. Depending on the properties of lens


12


or another optical component, spatial resolution of laser energy at the target position can approximately equal the mechanical resolution of positioning virtual source


18


multiplied by a ratio of distance J to distance H. In the case where mechanical resolution is about 5 micrometer (μm) and the ratio J/H is about 0.1, spatial resolution can be about 0.5 μm.




Mechanical resolution in laser device


10


is essentially the minimum controlled displacement per step of stepper or servo motors used to move virtual source


18


. In other devices within the scope of the present aspect of the invention, mechanical resolution could be related to movement of optical components, sample targets, and other devices. Spatial resolution in laser device


10


is essentially the minimum controlled displacement of laser energy at target position


14


. As a numeric measure of resolution, e.g. μm, decreases in value, finer resolution is provided and resolution is thus described to increase. As the numeric measure of resolution increases in value, less fine resolution is provided and resolution thus decreases. In the exemplary case of chemical imaging, finer resolution provides improved imaging so it follows that resolution is properly described as greater.




Preferably, at least one of distance H and distance J in a laser device can be altered, modifying the spatial resolution. In laser device


10


, decreasing distance H by moving lens


12


closer to virtual source


18


also increases distance J and thus decreases spatial resolution. However, distance J and distance H can be independently altered and increase or decrease the ratio to accordingly modify spatial resolution. Distance J and distance H can also be altered without modifying spatial resolution.




Mechanical resolution of positioning a laser source can be less than spatial resolution of laser energy in at least one direction of laser source motion. For example, in laser device


10


, mechanical resolution of laterally positioning virtual source


18


can be less than lateral spatial resolution of laser energy


8


at target position


14


. In keeping with the principles described herein, mechanical resolution of vertically positioning virtual source


18


can be less than vertical spatial resolution of laser energy


8


at target position


14


. It is further conceivable that lateral and vertical spatial resolution could exhibit different values. The different values can be the result of different values for lateral and vertical mechanical resolution and/or different optical effects for lateral source positioning compared to vertical source positioning.





FIGS. 3A-3C

provides another of several possible examples of a laser device and can be used to illustrate the concept of mechanical resolution being less than spatial resolution in both lateral and vertical positioning of a laser source.

FIGS. 3A-3C

show a gimbal system


100


placed on a magnet


70


. Although the structure of gimbal system


100


is adapted to rest on magnet


70


, those of ordinary skill will recognize from the descriptions herein that gimbal system


100


can be adapted to provide described advantages in a variety of other applications. Gimbal system


100


includes a bracket


110


resting on or attached to magnet


70


. Bracket


110


provides a platform for stable attachment of arch


104


including a top pivot


106


. A lateral index frame


112


is rotationally mounted on top pivot


106


such that lateral index frame


112


can rotate about top pivot


106


. Lateral index frame


112


includes a bottom pivot


108


positioned such that top pivot


106


and bottom pivot


108


define a lateral index about which lateral index frame


112


rotates. Bottom pivot


108


can be mounted to an additional device (not shown) stabilizing the position of pivot point


108


with respect to the indicated lateral index. One example of such additional device includes a height adjustment device that can be used to raise and lower lateral index frame


112


sliding on top pivot


106


.




Gimbal system


100


further includes a vertical index frame


114


linked to lateral index frame


112


at pivots


116


. Vertical index frame


114


in turn includes an optical bench


118


. Vertical index frame


114


can thus be rotationally mounted to lateral index frame


112


such that pivots


116


define a vertical index. In the examples of

FIGS. 3A-3C

, the described vertical index and lateral index intersect, although it is conceivable that lateral and vertical indices might not intersect.




In gimbal system


100


, a laser source can be linked to optical bench


118


such that gimbal system


100


comprises a manipulation mechanism of the laser source. Gimbal system


100


thus exemplifies a manipulation mechanism providing an approximate center of lateral pivot for laser source motion as well as an approximate center of vertical pivot for laser source motion. Vertical motion of optical bench


118


rotates about pivots


116


and lateral motion of optical bench


118


rotates about top pivot


106


and bottom pivot


108


. An optical component such as lens


12


, can be placed within magnet


70


such that a lateral index of the optical component coincides with the lateral index of gimbal system


100


and a vertical index of the optical component coincides with the vertical index of gimbal system


100


. A target position can also be defined such that a distance H and distance J as described in

FIG. 1

are provided where distance H is greater than distance J. When spatial resolution approximately equals mechanical resolution multiplied by a ratio of distance J to distance H, the same ratio J/H can apply to both lateral mechanical resolution and vertical mechanical resolution. Altering of at least one of distance H and distance J can thus modify lateral spatial resolution in a similar manner to vertical spatial resolution.




The possibility of altering distance H and distance J, especially where distance H can be greater than distance J, can be used to an advantage. According to another aspect of the invention, a laser device can include a target position located within an adverse environment, an optical component separated from the target position, and a laser energy source located outside the adverse environment. The laser device further includes a laser source manipulation mechanism comprising electro-mechanical parts all of which are located outside the adverse environment. The manipulation mechanism aims the laser source through the optical component at the target position. As one example, the adverse environment can include at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. Possible examples of hazardous zones include zones that may damage or contaminate the laser energy source or electro-mechanical parts of manipulation mechanism such as corrosive, toxic, radioactive, etc. environments in addition to other adverse environments listed above. An adverse environment may further include an environment toward which the laser source or parts of the manipulation mechanism may be adverse. For example, parts of the laser device might not be suitable for operation in a clean room environment even when the clean room environment does not damage or contaminate the laser device.




As shown in

FIG. 1

, an apparatus containing or generating an adverse environment can rest on footings


16


such that virtual source


18


, a lateral stepper


20


, and a vertical stepper


22


can be outside the adverse environment. In the particular example of

FIG. 1

, lens


12


is located within the adverse environment generated between footings


16


along with target position


14


. However, lens


12


could be moved outside the adverse environment, decreasing distance H and increasing distance J. Also, target position


14


could be moved closer to virtual source


18


but within the adverse environment between footings


16


while maintaining distance J as shown and placing lens


12


outside the adverse environment.





FIGS. 6 and 7

show one example of a target position located within an adverse environment and a laser source and electro-mechanical parts located outside the adverse environment.

FIGS. 6 and 7

show respective side and top views of target position


14


located within a vacuum system


72


wherein the portion of the vacuum system surrounding target position


14


is further within magnet


70


. Magnet


70


generates a high magnetic field that may hinder operation of an electro-mechanical part. Accordingly, a lateral stepper and vertical stepper (not shown) are located outside an adverse portion of such high magnetic field and are associated with virtual source


18


. Footings


16


are shown in

FIG. 6

with magnet


70


resting thereon. Lens


12


is thus also located within the high magnetic field. The distance between lens


12


and virtual source


18


allows protection of a manipulation mechanism for aiming virtual source


18


as well as resolution enhancement as discussed herein.




A further desire in increasing reproducible aiming of a laser device includes indexing to provide the ability to return laser aiming to a particular location at a target position. According to a further aspect of the invention, a laser device includes a target position, and optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component. The laser device further includes a laser source manipulation mechanism having a mechanical index. The mechanical index includes a pivot point for laser source lateral motion and a reference point for laser source vertical motion. Lateral displacement of the laser source can produce a related, predictable lateral displacement of laser energy at the target position as directed through the optical component. The lateral displacement may be referenced to the mechanical index such that return of the laser source to a particular position with respect to the mechanical index also returns the laser energy to a corresponding target position. In keeping with another aspect of the invention, laser energy lateral displacement at the target position can approximately equal laser source lateral displacement multiplied by the ratio of distance J to distance H.




In the case where distance J equals distance H, mechanical resolution can equal spatial resolution. However, such configuration can still provide the advantage of locating selected parts of a laser device outside an adverse environment, as well as other advantages. Distance J may even be greater than distance H. Such a configuration may provide less resolution at the target, however, it may allow laser energy to traverse greater distances and/or cover larger target areas. This can be useful in precise mapping or surveying of geography or in controlling robotic manufacturing of large parts. Additionally, a laser device might be used for tracking moving objects in either configuration J>H, J=H, or J<H. In the case of J>H, controllers may more slowly displace a laser source compared to the moving object to maintain contact with the object. For example, a laser source moving at one meter per second with a J/H ratio of 27 can track a vehicle travelling at 60 miles per hour.




Laser device


10


shown in

FIG. 1

provides one example among several possibilities of a mechanical index. A lateral index


38


can be defined for lens


12


. A lateral index can be similarly defined for other optical components. Laser device


10


also includes a pivot point


36


having an approximate center of lateral pivot for the laser source approximately coincident with lateral index


38


. Accordingly, pivot point


36


can comprise a mechanical index of a manipulation mechanism for virtual source


18


comprised by laser device


10


. Virtual source


18


is thus indexed to lens


12


. Such indexing can provide that laser energy from virtual source


18


passes through lateral index


38


regardless of vertical displacement of virtual source


18


. As farther described herein, the structure and operation of a laser source, such as virtual source


18


, combined with a mechanical index can also provide laser energy passing through lateral index


38


throughout varying positions of lateral displacement. Laser aim can thus be auto aligned to lateral index


38


during laser source lateral and/or vertical motion.




Laser device


10


also accommodates vertical displacement of virtual source


18


. Vertical stepper


22


lifts one end of a vertical operating rod


26


nearest vertical stepper


22


. The opposite end of vertical operating rod


26


swivels about a pivot point


6


and imparts angular motion to a ratio arm


32


also about pivot point


6


. The end of ratio arm


32


opposite pivot point


6


thus moves in an arc. Instead of linking vertical operating rod


26


to ratio arm


32


as shown, vertical operating arm


26


can be attached along ratio arm


32


above pivot point


6


. In such case, ratio arm


32


can still rotate about pivot point


6


. However, as vertical stepper


22


lifts one end of vertical operating rod


26


imparting angular motion to ratio arm


32


, vertical operating rod


26


rotates about a virtual pivot point past the opposite end of vertical operating rod


26


. Other variations in imparting angular motion to ratio arm


32


are conceivable according to the knowledge of those skilled in the art and are encompassed herein.




Ratio arm


32


forms a part of a Peaucellier linkage. The Peaucellier linkage of

FIG. 1

further includes a ratio arm


34


, support arms


30


, and diamond arms


28


. Ratio arm


34


essentially defines the distance from pivot point


6


to the point where support arms


30


are joined together. As an alternative, ratio arm


34


can be replaced by a bracket attached to other structural features, maintaining a desired distance between pivot point


6


and the point where support arms


30


are joined together. Ratio arm


32


is linked at a pivot point


4


to two of diamond arms


28


. Pivot point


36


described above exists at an opposite corner in relation to pivot point


4


. As vertical operating rod


26


imparts angular motion to ratio arm


32


, pivot point


4


moves in an arc along with the end of ratio arm


32


. Such arcuate motion of pivot point


4


causes pivot point


36


to move vertically along a linear path. Given the disclosure herein, a variety of Peaucellier mechanisms could be used as an alternative to accomplish the described functions of the apparatus in FIG.


1


.




Accordingly, pivot point


36


can move vertically in a linear motion tracking a linear center of lateral pivot for the laser source and coinciding with lateral index


38


. By altering the relative lengths of ratio arm


32


and


34


, pivot point


36


can instead track a curve. For example, pivot point


36


could track a convex or concave surface of a lens. Such a curve tracking feature may have useful application in one of the various possible uses of the aspects of the present invention.




Preferably, vertical displacement of a manipulation mechanism index produces a related, predictable vertical displacement of laser energy at the target position as directed through an optical component. In

FIG. 1

, vertical displacement of pivot point


36


vertically moves operating rod


24


, in turn vertically moving inner components of virtual source


18


. A pendulum can be linked to the laser source such that vertical displacement of the mechanical index controls a vertical angle of laser energy departure from the laser source at least in part with the pendulum.





FIG. 2

provides a schematic of lens


12


having a lateral index


38


. Lateral source displacement


42


is shown for virtual source


18


and a vertical angle of departure


102


is also shown. Lateral source displacement


42


is indexed to lateral index


38


. Accordingly, lateral laser aim is auto aligned through lateral index


38


and produces lateral energy displacement


46


at target position


14


. Variation in vertical angle of departure


102


is inverted through lens


12


providing vertical energy displacement


88


as shown superimposed at target position


14


. A laser device functioning as shown is

FIG. 2

can be described to include a single index scan mechanism. The optional pendulum described above that can be linked to a laser source rotates about the line representing lateral source displacement


42


. By converting vertical displacement of a mechanical index, such as pivot point


36


, to a vertical angle of laser energy departure, vertical displacement of laser energy at target position


14


can be accomplished. Accordingly, pivot point


36


does not comprise a pivot point for virtual source


18


vertical motion but rather comprises a reference point. Virtual source


18


is still indexed to pivot point


36


as to lateral aiming of virtual source


18


. However, vertical motion is not indexed to pivot point


36


since the true pivot point for virtual source


18


vertical motion lies within virtual source


18


.




Vertical displacement of laser energy at target position


14


can occur by moving laser energy vertically across the face of lens


12


or another optical component. However, the vertical displacement at lens


12


corresponding to vertical energy displacement


88


at target position


14


might not be a linear relationship. Correction for a non-linear correspondence is possible but may be cumbersome. The magnitude of lateral source displacement


42


preferably corresponds in a linear relationship to the magnitude of lateral energy displacement


46


at target position


14


.




Laser device


10


is described herein as including a lateral index passing through an optical component, but according to

FIG. 2

does not include a vertical index passing through lens


12


. However, the apparatuses described herein as useful for establishing a lateral index can be altered to establish a vertical index. For example, pivot point


36


can be used to establish at least one of a lateral index and a vertical index.




According to a still further aspect of the invention, a laser device includes an optical component, a laser energy source separated from the optical component, and a laser source manipulation mechanism including a Peaucellier linkage. The manipulation mechanism aims the laser source through the optical component. The Peaucellier linkage can be used to impart vertical motion and can instead be oriented to impart lateral motion.




Further advantages exist to combining a vertical index and a lateral index in a laser device. Another aspect of the invention provides a laser device including an optical component having a vertical index and a lateral index that intersect at an origin, a laser energy source aimed at the origin, and a laser source manipulation mechanism. The manipulation mechanism links vertical and lateral laser source motion to the respective vertical and lateral indices and auto aligns laser aim through the origin during laser source motion. Gimbal system


100


shown in

FIGS. 3A-3C

provides one example of a device that can be comprised by the described manipulation mechanism and exhibit the stated features. A lateral index can be defined for an optical component that coincides with a lateral index defined by top pivot


106


and bottom pivot


108


of lateral index frame


112


. A vertical index can be defined for an optical component that coincides with a vertical index defined by pivots


116


of vertical index frame


114


. Optical bench


118


can be linked to a laser source such that lateral laser source motion is physically linked to the optical component lateral index. Similarly, vertical laser source motion can be physically linked to the optical component vertical index. When optical component vertical and lateral indices intersect at the origin, laser aim can be auto aligned through the origin during laser source motion.





FIG. 4

provides a schematic of lens


12


having lateral index


38


and a vertical index


34


. Vertical source displacement


40


is shown for a virtual source


68


and lateral source displacement


42


is also shown. Vertical source displacement


40


is indexed to vertical index


44


and lateral source displacement


42


is indexed to lateral index


38


. Since lateral index


38


and vertical index


34


intersect, laser aim is auto aligned through the origin where the indices intersect during laser source motion. Orienting lens


12


to position the origin at the center of lens


12


allows laser energy to pass directly through lens


12


forming a corresponding image of applied laser energy at target position


14


. Lateral energy displacement


46


and vertical energy displacement


48


are shown superimposed at target position


14


.




Generally speaking, a gimbal is a device with two mutually perpendicular and intersecting axes of rotation, providing angular motion in two directions.

FIGS. 3A-3C

provide an example of a gimbal adapted to resting on magnet


70


, laser aiming into magnet


70


, and linking with a virtual source such as shown in FIG.


5


. Other adaptations of a gimbal providing manipulation mechanism features and advantages are conceivable for other applications and laser sources. One possible adaptation includes a virtual gimbal system. A virtual gimbal system, such as a set or array of laser beams and sensors, can be designed to track position of a laser energy source relative to a target position. Information from the sensors could provide feedback to a control system maintaining the desired laser aim. A virtual gimbal system could facilitate using the laser devices described herein for hazardous zones or across distances greater than practical for a mechanical gimbal system. A virtual gimbal system could nevertheless embody the concept of providing at least one of a lateral index and a vertical index. Such indices could be virtual, rather than dictated by a physical link to the laser energy source.




Notably, the dual indexing of virtual source


68


to a point within lens


12


allows precise reproduction of laser energy position at target position


14


. Further, mechanical resolution of vertical source displacement


40


and lateral source displacement


42


can be enhanced for vertical energy displacement


48


and lateral energy displacement


46


. At least one of vertical source displacement


40


and lateral source displacement


42


can be linear, as shown. Also, target position


14


can be planar, as shown. For the

FIG. 4

schematic of a dual index scan mechanism, the magnitude of vertical and lateral source displacement


40


,


42


each correspond in a linear relationship to a magnitude of vertical and lateral energy displacement


48


,


46


, respectively, at target position


14


. A linear relationship for positioning source


68


and obtaining related, predictable positioning of laser energy can be very convenient and assist in achieving a high level of reproducibility.




In another aspect of the invention, a laser energy source has a lateral rotational axis during lateral motion and a vertical rotational axis during vertical motion. The lateral axis and vertical axis can intersect at an axes origin from which the laser energy emanates independent of laser source position. A laser source manipulation mechanism can laterally and vertically position the laser source and easily maintain laser aim through an optical component given the two rotational axes of the laser source. Further, the laser source can be wavelength independent throughout both lateral and vertical motion.




Turning to

FIG. 5

, a cross sectional view of virtual source


68


is shown. Laser energy


50


passes through virtual source


68


emanating from laser exit


60


at the surface of a prism


58


. Upon exiting a true laser source, such as shown in

FIG. 7

, laser energy


50


enters virtual source


68


at the top through lateral transmission prism


52


. Lateral transmission prism


52


guides laser energy into lateral rotation prism


54


. Laser energy exits lateral rotation prism


54


to enter prism


56


which turns the beam 180° applying the lateral rotation from prism


54


to laser energy entering prism


58


. Prism


58


rotates about a lateral axis


64


including laser exit


60


.




Prism


58


can be mounted on a kinematic stage


66


for precise final positioning. A four axis kinematic stage Model 6071 available from New Focus, Inc. in Santa Clara, Calif. is one example of a suitable kinematic stage


66


. Kinematic stage


66


can be mounted on a swing


120


that has a vertical axis


62


normal to a desired path of laser energy emanating from laser exit


60


. Vertical axis


62


can be colinear with laser energy


50


from prism


56


. Accordingly, laser energy


50


emanates from an axes origin of intersecting lateral axis


64


and vertical axis


62


. Swing


120


is shown nested within a first box


122


and coupled to first box


122


with vertical bearings


130


. Vertical bearings


130


allow swing


120


to rotate within first box


122


about vertical axis


62


. First box


122


is in turn nested within a second box


124


and coupled thereto with lateral bearings


128


. First box


122


thus rotates within second box


124


about lateral axis


64


. Accordingly, both rotations about lateral axis


64


and vertical axis


62


are combined at a single point coinciding with laser exit


60


on a hypotenuse of prism


58


. Maintaining laser energy


50


normal to prism faces at all angles ensures wavelength independence of virtual source


68


such that prism changes can be avoided when a wavelength of laser energy


50


is altered. Although virtual source


68


is achromatic, the odd number of refractions causes the profile of the laser energy


50


emanating from laser exit


60


to be the mirror image of laser energy


50


entering virtual source


68


.




Second box


124


is positioned within a third box


126


acting as a guide for second box


124


during vertical motion. Second box


124


preferably moves approximately linearly within third box


126


. Vertical motion can be accomplished by a variety of mechanisms, including an auger screw (not shown) interfaced with second box


124


behind laser exit


60


. Such an auger can be operated by a variety of stepper and/or servo motors. Virtual source


68


lateral motion preferably occurs approximately linearly as well. Lateral motion can be accomplished with another auger screw (not shown) interfaced to third box


126


and also operated by a stepper and/or servo motor.




An absolute position of laser exit


60


can be determined independent of the mechanical resolution and thus confirm where laser exit


60


is located after lateral and/or vertical displacement. For indexed lateral and/or vertical displacement, knowledge of absolute source position can provide knowledge of absolute energy position at the target. While the mechanical resolution describes the amount of laser source motion, absolute position describes the ending location after such motion. Absolute position can be determined with feedback from optical encoders for each axis of motion of the virtual source. The encoders can be incorporated into the virtual source and exhibit a resolution less than the mechanical resolution. The encoders can thus provide increased energy position resolution at the target. As an example, the encoders, can have a resolution of about 0.1 μm in the virtual source. Absolute position at the laser source can be enhanced to greater resolution at the target. For a J/H ratio of 0.1, an absolute source position resolution of 0.1 μm yields an absolution energy position resolution of 0.01 μm at the target.




An operating rod of a laser source manipulation mechanism can be linked to virtual source


68


. For example, optical bench


118


of gimbal system


100


shown in

FIG. 3

can be linked using a low friction slide attached to swing


120


below prism


58


. Virtual source


68


is displaced approximately linearly during lateral motion and optical bench


118


rotates laterally along with lateral index frame


112


about a lateral index defined by top pivot


106


and bottom pivot


108


. The low friction slide allows for small differences in distance from virtual source


68


to the lateral index of gimbal system


100


as virtual source


68


traverses the desired path. Similar changes in distance and allowances for such changes can occur while virtual source


68


traverses a desired vertical path with optical bench


118


rotating along with vertical index frame


114


about a vertical index defined by pivots


116


.




Even though laser source


68


can move approximately linearly in both lateral and vertical motion, laser energy


50


aim can be auto aligned throughout such motion. Laser aim can thus be auto aligned to vertical and/or lateral indices of an optical component during laser source motion. Virtual source


68


linked to a laser source manipulation mechanism with a slide attached to swing


120


provides one example of auto alignment. As virtual source


68


moves laterally and linearly from an approximate center of lateral pivot coincident with an optical component lateral index, first box


122


rotates about lateral axis


64


and laser energy


50


aim is maintained along the optical component lateral index. Similarly, as virtual source


68


moves vertically and linearly from an approximate center of vertical pivot coincident with the optical component vertical index, laser energy


50


aim is maintained along the optical component vertical index.




As can be appreciated from

FIG. 4

, vertical and lateral linear displacement of laser source


68


changes distance H to the optical component. However, for a planar target position


14


, distance J to the optical component also increases. Thus, the ratio J/H remains unchanged throughout displacement of laser source


68


. If vertical and/or lateral laser source displacement was arcuate instead and distance H remained constant, then ratio J/H would change throughout displacement for a planar target position


14


.




Turning to

FIGS. 6 and 7

, a laser desorption spectrometer is shown comprising the auto alignment aspect and other aspects of the invention described herein.

FIG. 6

shows a side view of selected portions of a laser desorption spectrometer and

FIG. 7

shows a top view.

FIG. 6

shows laser energy


50


emanating from virtual source


68


and passing through lens


12


onto target position


14


. Target position


14


is located within a vacuum system


72


at the tip of a probe bar


132


. The portion of vacuum system


72


containing target position


14


is also within a high magnetic field that can hinder operation of electro-mechanical devices. The high magnetic field is generated by magnet


70


having a magnitude of up to about 7.0 Tesla (70,000 Gauss). “High” magnetic fields are typically greater than about 50 Gauss, but some electro-mechanical devices may exhibit a particular sensitivity to magnetic fields such that a lower magnitude of a high magnetic field could hinder operation of the electro-mechanical device. At least one desorbed energy detection cell can be provided to allow operation as a laser desorption spectrometer.

FIG. 6

shows two detection cells


74


positioned within magnet


70


.




Virtual source


68


rests on a lateral slide


86


in turn resting on a footing


84


and magnet


70


rests on footings


16


, allowing precise and accurate reproduction of laser energy


50


position at target position


14


. A travel limit


76


is shown as a function of physical constraints for the particular arrangement in

FIGS. 6-7

. The small center bore of magnet


70


and the location of target position


14


within magnet


70


constrain the travel limit as shown since magnet


70


obstructs laser energy


50


at a larger travel limit. Certainly, travel limit


76


can be altered depending on the location of target position


14


within some device and the physical structure of such device. The upper travel limit


68




a


and lower travel limit


68




b


are shown about 9° apart. Notably, laser energy


50


from virtual source


58


continues to pass through lens


12


at upper and lower travel limits


68




a,b


since virtual source


68


is indexed to vertical index


44


shown in FIG.


7


.




Although not shown in

FIGS. 6-7

, a laser source manipulation mechanism as described herein can be used to index virtual source


68


to vertical index


44


. Gimbal system


100


of

FIGS. 3A-3C

is one example of a suitable manipulation mechanism. Gimbal system


100


also includes a convenient optical bench


118


.

FIG. 6

shows an iris


78


, a beam expander


80


, and a variable beam splitter


82


that process laser energy


50


between virtual source


68


and lens


12


. Such beam processing devices can be located on optical bench


118


of gimbal system


100


or could be located using some other structure. Since optical bench


118


can be linked to virtual source


68


with a low friction slide, the beam processing devices mounted on optical bench


118


remain in alignment throughout vertical as well as lateral laser source motion. Iris


78


and beam expander


80


provide a desired amount of laser energy fluence to a target position and other components of a laser system may be provided according to the knowledge of those skilled in the art. Variable beam splitter


82


also assists in providing a desired amount of laser fluence to a target position and allows measurement of laser fluence using an energy detector


90


shown in FIG.


7


.





FIG. 7

further shows other components of a laser system such as a true laser source


92


generating laser energy


50


that passes through a separations package


94


isolating desired wavelengths of energy and passes through a dye laser head


96


. A prism


98


turns laser energy


50


90 ° to enter virtual source


68


at lateral transmission prism


52


shown in FIG.


5


.

FIG. 7

also shows lateral motion of virtual source


68


along lateral slide


86


within travel limit


76


. Notably, lateral source motion is indexed to lateral index


38


shown in FIG.


6


. Lateral indexing can be provided by a laser source manipulation mechanism described herein, such as gimbal system


100


in

FIGS. 3A-3C

and laser device


10


shown in FIG.


1


. Laser device


10


is expressly described as providing a lateral index and is not shown as providing a vertical index. Preferably, the manipulation mechanism selected for a laser source allows the laser source to be placed in scanning motion. A highly reproducible laser energy scanning device can be particularly useful in a laser desorption spectrometer such as shown in

FIGS. 6-7

.




In a further aspect of the invention, a laser device such as one of those described herein can include a target position within a high magnetic field and a damping device operating under Lenz' Law to reduce vibration of the target position. For the device in

FIGS. 6-7

, vacuum system


72


can include vacuum pumps that generate vibrations transmitted through vacuum system


72


to probe bar


132


and cell supports of detection cells


74


. Such vibrations can impede aligning the same spot twice on a target with laser energy even when no manipulation of the laser source occurs. Magnet


70


can be a superconducting magnet providing a large magnetic field of potential advantageous use in damping the described vibrations.




Lenz' Law states that a magnetic flux can be induced in a conducting loop inside a magnetic field. If a force, such as physical movement of the conducting loop, causes a change in the induced magnetic flux, an electromotive force current will be induced such that its magnetic field will oppose the change. Accordingly, fabricating at least some components of the cell supports and/or probe bar


132


from a non-ferromagnetic, high conductivity material, such as aluminum and/or copper, can dampen vibrations within magnet


70


. Aluminum and oxygen free high conductivity (OFHC) copper can be used instead of typical non-ferromagnetic materials such as titanium or 314 or 316 stainless steel. Aluminum and OFHC copper are non-ferromagnetic, but exhibit electrical conductivities sufficient to take advantage of the effect known as magnetic damping depending upon Lenz' Law. Other materials may be suitably used instead of or in combination with aluminum and/or OFHC copper, including non-ferromagnetic materials exhibiting high enough electrical conductivity suitable for a desired application. Accordingly, vibrations from pumps associated with vacuum system


72


that are conveyed through the cells, cell supports, and/or probe bar can be damped as a result of the opposing torque generated in magnet


70


.




Cell supports for detection cells


74


can be suspended from the housing of vacuum system


72


on rods attached to vacuum system


72


with articulating joints. Such joints provide support for the cell and additionally exhibit sufficient degrees of freedom to allow detection cells


74


to stabilize within the magnetic field independent of vacuum system


72


. Care may be taken in judging the amount of high conductivity non-ferromagnetic material to be placed in the magnetic field since the time and mechanical force used to insert, relocate, and retrieve the assembly (cell, cell supports, probe bar and supports) from the magnetic field may exceed the operator's and/or designing engineer's desired parameters. This is especially true for superconducting magnets whose structure contains critical welds that should not be subjected to excessive force to avoid permanent damage to the magnet. Adjustments to the induced field can be made by altering physical dimensions of parts and adding slits or removing unneeded portions of parts to mediate the induced current. For example, an aluminum support ring might be used to secure a stainless steel probe bar, wherein the support ring provides the damping effect.




Accordingly, the laser device according to the present aspect of the invention can be comprised by a laser desorption spectrometer and the damping device can contain a probe bar including the target position and cell supports of at least one desorbed energy detection cell. The probe bar and cell supports can be subject to Lenz' Law. The high magnetic field can be greater than about 50 gauss to effectively utilize Lenz' Law, or preferably greater than about 1 Tesla. However, a different magnetic field may be suitable depending on the application. The suitable magnetic field can be determined by Newton's second law stating that Force=Mass×Acceleration. That is, the suitable magnetic field depends on the force induced thereby, the mass of the object being damped, and the displacement and frequency caused by vibrations (acceleration). Accordingly, the dimensions (and hence mass) and electrical conductivity of cells, cell supports, and/or probe bar can affect damping as well the particular vibration source. A different magnetic field may be used to induce the force desired under the various possible conditions to operate as an effective damping device.




EXAMPLE




An internal source laser desorption microprobe Fourier transform mass spectrometer (LD-FTMS) was developed using twelve design goals: 1) movement of laser energy relative to a sample rather than sample manipulation to avoid problems with a high magnetic field and superconducting magnet geometry, 2) variable step intervals for laser energy resolution of at least about 0.5 μm, 3) highly reproducible laser energy positioning to enable successive analyses for depth-profiling studies, 4) absolute laser positioning to within 0.1 μm or less, 5) wavelength independent scanning system, 6) automated focusing to adjust for different energy wavelengths, 7) variable laser spot size down to at least about 2 μm with a single focusing lens that can be easily exchanged for different spot sizes, 8) external optics for simple laser energy alignment, 9) circular laser spots, 10) Gaussian laser energy profile and uniform energy deposition, 11) sample sizes up to about 2 centimeters (cm) in diameter, and 12) modular cells and cell supports allowing multiple cell configurations.





FIGS. 6 and 7

show selected features of a LD-FTMS developed according to the described goals. Selected parts of the LD-FTMS cells, cell supports, probe bar, and/or probe bar supports were manufactured from aluminum and OFHC copper instead of typical titanium or 316 stainless steel to take advantage of magnetic damping depending upon Lenz' Law. Because typical LD-FTMS technology uses titanium or 316 stainless steel that is not affected by magnetic fields, some concern existed that the use of aluminum and copper instead might adversely affect the magnetic field of magnet


70


. Homogeneity of the magnetic field could not be mapped with probe bar


132


and detection cells


74


installed, however, no adverse effects were observed during calibrations, analyses, etc.




A Nd:YAG laser model Surelite I-10 from Continuum of Santa Clara, Calif. was provided as true laser source


92


and included a separations package


94


. A grating tuned dye laser head model Jaguar C from Continuum was provided as dye laser head


96


. Settings of variable beam splitter


82


, beam expander


80


, and iris


78


were selected to provide a typical laser energy at target position


14


of about 2 microjoules, giving a laser fluence of 4×10


8


Watts/cm for a 10 μm spot. Lens


12


was located external to vacuum system


72


allowing easy exchange of lenses and adjustment of focal length. Focal length was adjusted by remote control of a stepper motor powered by a microstepping controller in turn driving a vacuum actuator at 40 turns per inch. The vacuum actuator was linked to a lens mount carriage that housed lens


12


with a 5 foot fiberglass rod, thus positioning the stepper motor distantly and outside the 50 Gauss line of magnet


70


.




A manipulation mechanism similar to gimbal system


100


of

FIG. 3

was manufactured from aluminum rail from 80/20 Inc. of Columbia City, Ind. The aluminum rail geometry provided torsional rigidity and was self-damping for low mode vibrations. The lateral and vertical indices of lens


12


were aligned to coincide with the approximate centers of lateral and vertical pivot for gimbal system


100


. Lateral and vertical indices of lens


12


intersected at the center of lens


12


and provided auto alignment to lens


12


center. A virtual source similar to virtual source


68


shown in

FIG. 5

was linked to optical bench


118


of gimbal system


100


with a low friction slide attached to swing


120


below prism


58


. The distance between virtual source


68


and the lens


12


center was maintained to at least about 1.3 meters (4 feet) which is outside the 50 Gauss line of magnet


70


. A maximum distance of about 4.6 meters (15 feet) was used due to laboratory constraints, but could be greater.




A lateral drive for virtual source


68


was used to provide 5 μm steps at virtual source


68


with a pitch of 2 turns per inch. A vertical drive was used to provide 1 μm steps at virtual source


68


with a pitch of 40 turns per inch.




A first lens was used having a focal length of 80 millimeters (mm) positioned accordingly from target position


14


and the virtual source was positioned 272 cm from the first lens. The virtual source was thus located about 201 cm from the edge of magnet


70


. The ratio of distance J to distance H was about 0.029 providing a spatial resolution at target position


14


of about 0.15 μm laterally and about 0.03 μm vertically. The smallest spot size obtainable was about 2 μm. The focal length of the first lens limited excursion of laser energy across target position


14


to about 1.25 cm laterally and vertically, which is less than the desired about 2 cm traverse.




A second lens was used having a focal length of 325 mm and the virtual source was located 247.5 cm from the second lens. The ratio of distance J to distance H was thus about 0.13 providing a spatial resolution at target position


14


of 0.66 μm laterally and 0.13 μm vertically. Although the lateral resolution was less than the desired 0.5 μm, lateral resolution could be increased by replacing the lateral drive with a device providing a finer pitch. The smallest practical laser spot size was about 4 μm and the laser energy at target position


14


could traverse about 5.1 cm along either index. Providing lens


12


external to vacuum system


72


allowed easy exchange of multi-element optics to produce smaller spot sizes if desired.





FIG. 8

shows a scanning electron micrograph (SEM) of an aluminum foil target with 4 laser shots from the corner of a larger array of 36×36 laser shots illustrating the quality and reproducibility. The original 36×36 array was made with single laser shots having an approximate diameter of 14 μm. The scanning feature of LD-FTMS was used to return to perimeter positions of the array and apply a second laser shot. Position A in

FIG. 8

is a single laser shot from the array interior and illustrates the circular shape of laser shots provided as the laser energy passes through the center of lens


12


, rather than through another part of lens


12


. The consistent circular shape regardless of spot position is advantageous in spectral analysis, simplifying calculations in comparison to systems producing ellipsoidal spots when laser energy is aimed off the center of lens


12


. Positions B, C, and D are double shots formed by returning to the shown positions after completing the array of single shots and illustrate the high level of reproducibility.





FIG. 9

shows a printed circuit board analyzed using the described LD-FTMS. The SEM in

FIG. 9

shows 12 laser spots having diameters of approximately 20 μm. The laser spots occur both on the phenolic portion of the composite board as well as across a gold trace having a width of about 115 μm. The arrows were added to identify the location of laser spots on the phenolic board since they are less distinct than laser spots on the gold trace. The mass spectra array from the laser spots is shown in FIG.


10


. Spectra from spots on the phenolic board were dominated by the isotope peaks for chlorine ion (Cl>) (m/z 34.969 and 36.966) and bromine ion (Br>) (m/z 78.919 and 80.917). Spectra for positions


5


-


9


clearly show a peak at m/z 196.967 representing gold ion (Au>). The laser spots at positions


4


and


10


are on the edges of the gold trace and exhibit a mixture of peaks from gold, chlorine, and bromine.




In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.



Claims
  • 1. A laser device comprising:a target position; an optical component separated a distance J from the target position; a laser energy source separated a distance H from the optical component, distance H being greater than distance J; a laser source manipulation mechanism exhibiting a mechanical resolution of positioning the laser source, the mechanical resolution being less than a spatial resolution of laser energy at the target position as directed through the optical component; at least one desorbed energy detection cell, the laser device being comprised by a laser desorption spectrometer.
  • 2. The device of claim 1 wherein a vertical index and a lateral index that intersect at an origin are defined for the optical component, the manipulation mechanism auto aligning laser aim through the origin during laser source motion.
  • 3. The device of claim 1 wherein the laser source manipulation mechanism comprises a mechanical index, the mechanical index comprising a pivot point for laser source lateral motion and a reference point for laser source vertical motion.
  • 4. The device of claim 1 wherein the target position is located within an adverse environment comprising at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone, the laser source and an electro-mechanical part of the manipulation mechanism being located outside the adverse environment.
  • 5. The device of claim 1 wherein the target position is located within a vacuum chamber also within a high magnetic field that can hinder operation of electro-mechanical devices.
  • 6. The device of claim 1 wherein the optical component comprises a lens.
  • 7. The device of claim 1 wherein the optical component comprises multi-element optics.
  • 8. The device of claim 1 wherein the laser source comprises a virtual source, the virtual source being separated the distance H from the optical component.
  • 9. The device of claim 1 wherein the laser source can be placed in scanning motion by the manipulation mechanism.
  • 10. The device of claim 1 wherein the laser source has a lateral rotational axis during lateral motion and a vertical rotational axis during vertical motion, the lateral axis and vertical axis intersecting at an axes origin from which the laser energy emanates independent of laser source position.
  • 11. The device of claim 1 wherein the mechanical resolution comprises both lateral and vertical mechanical resolution and the spatial resolution comprises both lateral and vertical spatial resolution.
  • 12. The device of claim 1 wherein the spatial resolution approximately equals the mechanical resolution multiplied by a ratio of distance J to distance H and wherein at least one of distance H and distance J can be altered, modifying the spatial resolution.
  • 13. The device of claim 1 wherein the manipulation mechanism comprises a Peaucellier linkage.
  • 14. A laser device comprising;a target position; a lens separated a distance J from the target position; a laser energy virtual source separated a distance H from the lens, distance H being greater than distance J; a virtual source manipulation mechanism exhibiting a mechanical resolution of positioning the virtual source, the mechanical resolution being less than a spatial resolution of laser energy at the target position as directed through the lens; and at least one desorbed energy detection cell, the laser device being comprised by a laser desorption spectrometer.
  • 15. The device of claim 14 wherein the virtual source has a lateral rotational axis during lateral motion and a vertical rotational axis during vertical motion, the lateral axis and vertical axis intersecting at an axes origin from which the laser energy emanates independent of virtual source position.
  • 16. The device of claim 14 wherein the mechanical resolution comprises both lateral and vertical mechanical resolution and the spatial resolution comprises both lateral and vertical spatial resolution.
  • 17. The device of claim 14 wherein the spatial resolution approximately equals the mechanical resolution multiplied by a ratio of distance J to distance H and wherein at least one of distance H and distance J can be altered, modifying the spatial resolution.
  • 18. A laser device comprising:an optical component having a vertical index and a lateral index that intersect at an origin; a laser energy source aimed at the origin; a laser source manipulation mechanism linking vertical and lateral laser source motion to the respective vertical and lateral indices and auto aligning laser aim through the origin during laser source motion; and at least one desorbed energy detection cell, the laser device being comprised by a laser desorption spectrometer.
  • 19. The device of claim 18 further comprising a target position separated a distance J from the optical component, wherein the laser source is separated a distance H from the optical component greater than distance J and wherein the manipulation mechanism exhibits a mechanical resolution of displacing the laser source less than a spatial resolution of displacing laser energy at the target position.
  • 20. The device of claim 18 wherein at least one of the lateral index and vertical index comprises a line.
  • 21. The device of claim 18 wherein the optical component comprises a lens.
  • 22. The device of claim 18 wherein the optical component comprises multi-element optics.
  • 23. The device of claim 18 wherein the laser source comprises a virtual source.
  • 24. The device of claim 18 wherein the laser source can be placed in scanning motion by the manipulation mechanism.
  • 25. The device of claim 18 wherein the laser source has a lateral rotational axis during lateral motion and a vertical rotational axis during vertical motion, the lateral axis and vertical axis intersecting at an axes origin from which the laser energy emanates independent of laser source position.
  • 26. The device of claim 18 wherein the lateral laser source motion is physically linked to the lateral index.
  • 27. The device of claim 18 wherein the vertical laser source motion is physically linked to the vertical index.
  • 28. The device of claim 18 wherein the manipulation mechanism comprises an approximate center of lateral pivot for laser source motion approximately coincident with the lateral index and an approximate center of vertical pivot for laser source motion approximately coincident with the vertical index.
  • 29. The device of claim 18 wherein the manipulation mechanism comprises a mechanical gimbal.
  • 30. The device of claim 18 wherein the manipulation mechanism comprises a virtual gimbal.
  • 31. A laser device comprising:a lens having a vertical index and a lateral index that intersect at an origin; a laser energy virtual source aimed at the origin; a virtual source manipulation mechanism linking vertical and lateral virtual source motion to the respective vertical and lateral indices and auto aligning laser aim through the origin during virtual source motion; and at least one desorbed energy detection cell, the laser device being comprised by a laser desorption spectrometer.
  • 32. The device of claim 31 wherein the virtual source has a lateral rotational axis during lateral motion and a vertical rotational axis during vertical motion, the lateral axis and vertical axis intersecting at an axes origin from which the laser energy emanates independent of laser source position.
  • 33. The device of claim 31 wherein the lateral and vertical virtual source motion is physically linked to the respective lateral and vertical indices.
  • 34. The device of claim 31 wherein the manipulation mechanism comprises an approximate center of lateral pivot for virtual source motion approximately coincident with the lateral index and an approximate center of vertical pivot for virtual source motion approximately coincident with the vertical index.
CONTRACTUAL ORIGIN OF THE INVENTION

This invention was made with Government support under Contract DE-AC07-99ID13727 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.

US Referenced Citations (3)
Number Name Date Kind
5852493 Monnin Dec 1998 A
5861550 Ray Jan 1999 A
5867522 Green et al. Feb 1999 A
Non-Patent Literature Citations (3)
Entry
Scott, J. R., et al, “Development of an Imaging Internal Laser Desorption Fourier Transform Mass Spectrometer,” Pittsburg, PA Mar. 4-9, 2001, p. 143.
Tremblay, P. L., et al, “An Automated Imaging Internal Laser Desorption Fourier Transform Mass Spectrometer for Surface Analysis,” 49th ASMS Conference on Mass Spectrometry and Allied Topics, Chicago, IL May 26-31, 2001.
Tremblay, P. L., et al “Laser Scanning Design for a Fourier Transform Mass Spectrometer,” 48th ASMS Conference on Mass Spectrometry and Allied Topics, Long Beach, CA Jun. 11-15, 2000.