Patent Application
20140192829
Projections by the Energy Information Agency and current Intergovernmental Panel on Climate Change (IPCC) scenarios expect worldwide electric power demand to double from its current level of about 2 terawatts electrical power (TWe) to 4 TWe by 2030, and could reach 8-10 TWe by 2100. They also expect that for the next 30 to 50 years, the bulk of the demand of electricity production will be provided by fossil fuels, typically coal and natural gas. Coal supplies 41% of the world's electric energy today, and is expected to supply 45% by 2030. In addition, the most recent report from the IPCC has placed the likelihood that man-made sources of CO2 emissions into the atmosphere are having a significant effect on the climate of planet earth at 90%. “Business as usual” baseline scenarios show that CO2 emissions could be almost two and a half times the current level by 2050. More than ever before, new technologies and alternative sources of energy are essential to meet the increasing energy demand in both the developed and the developing worlds, while attempting to stabilize and reduce the concentration of CO2 in the atmosphere and mitigate the concomitant climate change.
Nuclear energy, a non-carbon emitting energy source, has been a key component of the world's energy production since the 1950's, and currently accounts for about 16% of the world's electricity production, a fraction that could—in principle—be increased. Several factors, however, make its long-term sustainability difficult. These concerns include the risk of proliferation of nuclear materials and technologies resulting from the nuclear fuel cycle; the generation of long-lived radioactive nuclear waste requiring burial in deep geological repositories; the current reliance on the once through, open nuclear fuel cycle; and the availability of low cost, low carbon footprint uranium ore. In the United States alone, nuclear reactors have already generated more than 55,000 metric tons (MT) of spent nuclear fuel (SNF). In the near future, we will have enough spent nuclear fuel to fill the Yucca Mountain geological waste repository to its legislated limit of 70,000 MT.
Fusion is an attractive energy option for future power generation, with two main approaches to fusion power plants now being developed. In a first approach, Inertial Confinement Fusion (ICF) uses lasers, heavy ion beams, or pulsed power to rapidly compress capsules containing a mixture of deuterium (D) and tritium (T). As the capsule radius decreases and the DT gas density and temperature increase, DT fusion reactions are initiated in a small spot in the center of the compressed capsule. These DT fusion reactions generate both alpha particles and 14.1 MeV neutrons. A fusion burn front propagates from the spot, generating significant energy gain. A second approach, magnetic fusion energy (MFE) uses powerful magnetic fields to confine a DT plasma and to generate the conditions required to sustain a burning plasma and generate energy gain.
Important technology for ICF is being developed primarily at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), assignee of this invention, in Livermore, Calif. There, a laser-based ICF project designed to achieve thermonuclear fusion ignition and burn utilizes laser energies of 1 to 2 MJ. Fusion yields of the order of 10 to 20 MJ are expected. Fusion yields in excess of 200 MJ are expected to be required in a central hot spot fusion geometry if fusion technology, by itself, were to be used for cost effective power generation. Thus, significant technical challenges remain to achieve an economy powered by pure ICF energy.
In addition to ICF applications, there is broad interest in the area of high average power lasers for materials processing, drilling, cutting and welding, military applications, and the like. Frequency conversion of laser light can improve absorption coefficients in materials being processed or used in systems. Despite the progress made in high average power lasers and frequency conversion of output beams from such lasers, there is a need in the art for improved methods and systems related to lasers and frequency conversion.
According to the present invention, techniques related to optical systems are provided. More particularly, embodiments of the present invention relate to methods and systems for frequency converting laser input light. In a particular embodiment, a multi-crystal frequency converter system is provided with a unique angle tuning system for improved conversion efficiency of laser pulses that cover a wide range of intensity. The methods and systems described herein are applicable to a variety of laser and amplifier systems including high repetition rate, high average power lasers and amplifiers. The terminology “harmonic conversion” and “frequency conversion” as utilized herein refers to the process of frequency converting a laser beam at a fundamental frequency or wavelength to higher harmonics of the fundamental, such as the second, third and fourth harmonic.
The present invention relates to a frequency tripling system that is suitable for use with high power laser and amplifier systems and is characterized by high energy conversion efficiency. The frequency conversion system described herein is useful to a wide variety of laser applications including the inertial confinement fusion (ICF) laser for the Laser Inertial Fusion Energy (LIFE) system under development by the present assignee. A particular embodiment of the present invention described herein utilizes low absorption loss, highly deuterated potassium dihydrogen phosphate (DKDP) crystals with large apertures (typically 40×40 cm). However, embodiments of the present invention are not limited to this particular nonlinear crystal and other suitable nonlinear optical materials such as yttrium calcium oxyborate (YCOB) and lithium triborate (LBO) can be utilized, or crystals isomorphic to KDP and DKDP.
As described more fully throughout the present specification, some embodiments of the present invention utilize four and up to six crystals arranged in a “cascade” configuration including either type I or type II phase matching. In a particular embodiment, two or more second-harmonic generating crystals are optically coupled to two or more frequency mixing crystals, thereby providing a high power and high energy third harmonic beam of uniform polarization. In order to accommodate high repetition rates (e.g., up to 15 Hz in the LIFE application), embodiments utilize helium or other inert gas cooling of the crystal faces, either directed or guided by sapphire and/or fused silica optical plates in close proximity to the faces, or directly bonded to the faces. These plates may serve as windows. In addition, for ICF laser drivers, a continuous random phase aberration plate may be inserted between the second harmonic and third harmonic sections, patterned on a separate optical substrate or on one of the optical windows.
According to an embodiment of the present invention, a frequency conversion system is provided. The frequency conversion system includes a frequency doubler module disposed along a beam path and comprising a first plurality of non-linear crystals and a frequency tripler module disposed along the beam path and comprising a second plurality of non-linear crystals.
According to another embodiment of the present invention, a method of generating frequency converted light is provided. The method includes providing an input beam characterized by a fundamental wavelength and frequency converting a portion of the input beam to a doubled beam characterized by a doubled wavelength half the fundamental wavelength. Frequency converting the input beam includes transmitting the input beam through a first plurality of non-linear optical crystals and outputting the doubled beam and another portion of the input beam. The method also includes frequency converting the doubled beam and the another portion of the input beam to a tripled beam characterized by a tripled wavelength two thirds the doubled wavelength. Frequency converting the doubled beam and the remaining portion of the input beam comprises transmitting the doubled beam light and the remaining portion of the input beam through a second plurality of non-linear optical crystals and outputting the tripled beam.
According to a specific embodiment of the present invention, an optical system is provided. The optical system includes a laser source operable to output a laser beam at a fundamental wavelength and a frequency conversion system. The frequency conversion system includes a frequency doubler module including a first plurality of nonlinear optical crystals and a frequency tripler module including a second plurality of nonlinear optical crystals. The optical system also includes a control system coupled to the frequency conversion system and a diagnostics system coupled to the frequency conversion system.
Embodiments of the present invention are useful in a variety of laser systems, particularly, laser and amplifier systems that provide high power and high energy conversion efficiency at the third harmonic wavelength (e.g., 351 nm for Nd-based gain medium). These systems include, without limitation, ICF laser drivers for LIFE power plants, laser drivers for ICF experiments, lasers used to generate plasmas for high energy density studies, high repetition rate, high average power frequency converted lasers for materials processing, and the like.
Numerous benefits are achieved by way of the present invention over conventional techniques. For example, embodiments of the present invention provide methods and systems characterized by higher conversion efficiency than conventional systems. Additionally, embodiments enable thermal management of the frequency conversion crystals using one or more of several cooling architectures. These and other embodiments of the invention along with many of its advantages and features are described in more detail in conjunction with the text below and attached figures.
According to the present invention, techniques related to optical systems are provided. More particularly, embodiments of the present invention relate to methods and systems for frequency converting laser input light, also referred to as the process of harmonic conversion. In a particular embodiment, a multi-crystal frequency converter system is provided with a unique angle tuning scheme for improved conversion efficiency. The methods and systems described herein are applicable to a variety of laser and amplifier systems including high repetition rate, high average power lasers and amplifiers.
It has been demonstrated that frequency conversion of the fundamental wavelength at 1053 nm (1ω) to the second and third harmonic wavelengths of 527 nm (2ω) and 351 nm (3ω), respectively, in ICF systems allows for more efficient absorption of laser energy by the target. This frequency conversion process increases the efficiency of the laser target coupling for the direct or indirect compression (via x-rays) of inertially confined targets for nuclear fusion. The energy conversion efficiency of the fundamental light to the third harmonic, pulse shaping fidelity over a wide intensity range, precision of pulse timing, and creating the required peak third harmonic power at the target plane are important aspects of the LIFE system.
Embodiments of the present invention provide a multi-crystal architecture for efficiently converting the desired pulse shape for the LIFE system at the third harmonic wavelength using highly deuterated potassium dihydrogen phosphate (DKDP) crystals. Highly deuterated KDP is a non-linear optical material useful for frequency conversion in high-energy, high-peak power, and high average power laser and amplifier systems because of its potential low absorption and relatively low transverse stimulated Raman gain compared to conventional KDP and other harmonic crystals. Crystal sapphire or fused silica windows in close proximity to the DKDP crystals form cooling channels for flowing helium or other inert gas, or when bonded directly to the crystal surfaces, can extract heat due to absorption into the cooling channel. Other harmonic generation crystals can be used in alternative embodiments of the present invention, for example, YCOB for second harmonic conversion and/or LBO for second and third harmonic conversion and the discussion provided herein in relation to type I and type II phase matching and beam polarization as applied to DKDP is generally applicable to these alternative non-linear optical materials, including crystals isomorphic to KDP and DKDP.
As described more fully throughout the present specification, the multi-crystal frequency tripling architectures discussed herein provide frequency conversion systems with energy conversion efficiencies of 70% or greater, with temporally shaped optical pulses over wide intensity ranges, which are suitable for use in a variety of high-energy laser and amplifier systems including the LIFE system. Although some embodiments of the present invention are described in relation to four crystal or six crystal frequency tripling architectures, the present invention is not limited to these particular architectures and other embodiments utilize two or more second-harmonic generating crystals that are followed by two or more frequency mixing crystals in a “cascade” configuration, to provide the high-power and high-energy third harmonic beam in a high average power design as well as address thermal and stress management issues during high-average-power operation.
Embodiments of the present invention provide multi-crystal frequency tripler designs with pulse shape and beam mapping for optimized energy conversion efficiency to the third harmonic for laser systems.
Since the “foot” and “drive” pulses (considered separately) have similar peak intensities, a frequency converter can be designed to reach optimal efficiency as compared to frequency converting the “total” pulse with one converter. It should be noted that the focal planes of each pulse overlap on the target for the integrated pulse shape to match the pulse shape determined using ICF target physics. The overall energy conversion efficiency is thus the average of three times the “drive” converter efficiency plus one times the “foot” converter efficiency. A continuous random optical phase plate (CPP) maybe located between the second and third harmonic sections, and serves to homogenize the overlapped focal distributions of the “foot” and “drive” beams at the target plane, thus improving the “total” pulse shape fidelity required for ICF physics. Additional description related to the “foot” and “drive” pulses is provided in commonly assigned U.S. patent application Ser. No. 13/______ (Client Reference No. IL-12359; Attorney Docket No. 91920-795275(006010US)), incorporated by reference above.
In an embodiment, the “foot” and “drive” beam frequency converters are optimized with identical crystal phase-match types and thicknesses in order to provide interchangeability in the LIFE facility. The inventors have determined that an increase in overall energy conversion on the order of 2-3% can be achieved with individual optimized frequency converter designs for “foot” and “drive” beams and such designs can be utilized if the interchangeability of final harmonic components is not judged to be of higher systems engineering value. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.
In some embodiments, heat is removed from the components by flowing a cooling fluid in the space between the components, with a greater number of thinner components utilized in some situations to reduce the thermal load per component. As illustrated in
Referring to
The predetermined percentage at the doubled frequency and the second predetermined percentage of the original frequency are converted (i.e., mixed) in the second frequency conversion device 230 to produce a frequency tripled beam (i.e., 3ω) with a polarization aligned with the 1ω input light (i.e., the x-direction) propagating along the beam direction (i.e., the z-direction).
In an alternative embodiment, the first frequency conversion device can include a pair of Type II doublers and the input beam can be oriented at an angle (y) in order to produce the 1ω and 2ω beams between the first and second frequency conversion devices. As will be evident to one of skill in the art, the input beam can include components aligned with both the x-direction and the y-direction as appropriate to Type II doubling (i.e., two-thirds aligned with the y-direction and one-third aligned with the x-direction in this implementation).
As illustrated in
Referring to
As illustrated in
Single-crystal sapphire is a highly transparent window material (for wavelengths from 200 nm to over 3 μm), yet is moderately birefringent. Therefore, in some embodiments, sapphire plates are only used on the input face of the first doubler and the exit face of the second doubler in order to avoid additional phase-mismatch. Optically isotropic fused silica plates are used on interior surfaces in some embodiments Similarly, sapphire can be used on the input face of the first tripler or exit face of the last tripler crystal with fused silica utilized as the other windows. The birefringence axes of the sapphire is preferably matched to the polarization directions of the linear polarized fields to avoid depolarization losses. Gas flow cooling between the doublers, between the second doubler and the first tripler, as well as between tripler crystals or optical plates can be provided according to embodiments of the present invention, whether the plates are bonded or mounted separately and used as gas flow channels or gas flow directors.
The inventors have determined that the “cascaded” multi-crystal designs described herein may be impacted by harmonic field interference effects due to index of refraction dispersion in the cooling gas and/or optical window materials present between pairs of frequency doubler and tripler crystals. That is, the harmonic field (2ω) created in the first doubler crystal will optically interfere with the harmonic field (2ω) created in the second doubler, as the phase of the harmonic field in the second doubler is determined by the fundamental field (1ω) phases, and these are retarded relative to the harmonic field created in the first doubler, due to index dispersion in the intervening gas and/or optical plates. A similar effect will occur in the tripler crystal pair, but involve the fundamental field (1ω) and the two harmonic fields (2ω, 3ω). Accordingly, some embodiments of the present invention reduce or minimize the thickness of the gas cooling channels and optical window materials to minimize optical path differences due to dispersion. As mentioned earlier, the same “harmonic interference” effect occurs in the flowing gas coolant, however, the index dispersion is many orders of magnitude less than optical glass, so gas paths (up to several cm) can be tolerated. No harmonic interference will occur between the pair of doubler and pair of tripler crystals, so these can be separated as required by the engineering design of the crystal mounts, or to provide a location for the CPP if utilized, and stepper motor drives (for angle tuning as described below) with intervening optical plates or windows to guide the cooling gas as needed.
Referring once again to
For type I phase matching, the input polarization is linear and along the ordinary axis of the first doubler. As described more fully throughout the present specification, angle tuning (e.g., at large angles) away from ideal phase-matched second harmonic conversion is used in the type I doubling crystals to limit the conversion of the fundamental to the second harmonic, thereby maintaining the predetermined mix ratio for tripling. As described in relation to
Introducing an angle between the normal of the crystal surface with respect to the beam propagation direction results in an internal angle between the angle of the beam propagation with respect to the optic axis of the crystals, thereby changing the momentum mismatch between the fields. Thus, embodiments of the present invention, rather than achieving “perfect” phase matching, introduce a tuning angle deviation or so called “detuning” to improve the frequency conversion efficiency.
By detuning the phase matching condition of the doubler, for example, by an internal angle from “perfect” phase matching of between 200 and 300 gad, the double is not allowed to fully convert the fundamental light to the second harmonic, thus enabling the detuning angle to control the ratio of first to second harmonic light at the input of the tripler.
The use of multiple crystals in the doubler and tripler enables the angular detuning to alternate between adjacent crystals. This is shown in
For type II phase matching, the ratio of incident fundamental (lco) intensity along ordinary and extraordinary axes is 2:1. This provides the optimal 1:1 mix ratio of fundamental (1ω) and second harmonic (2ω) light to produce the third harmonic (3ω) in the tripler. For type I phase matching, the 2:1 mix ratio of fundamental to second harmonic light at the exit of the first doubler is achieved by angle tuning the doubler off of exact phase matching (referred to as detuning) by a predetermined angle. In some embodiments, the detuning angle ranges from a few microradians to several hundred microradians. As illustrated below, the detuning angle can vary for each crystal, for example, between 30 μrad and 300 μrad. In four crystal designs utilizing two type I doublers, further increases in dynamic range for frequency mixing in the tripler crystals can be achieved by angle detuning the two doublers in opposite directions (e.g., +280 and −240 μrad). This detuning is a larger amount than would be used in a conventional two-crystal type I/type II converter, since the objective is to achieve a 2:1 mix ratio at the exit of the second doubler (rather than the first doubler) over a wide range of fundamental (1ω) intensity incident on the first doubler. For a “triplet” of doubler crystals, some embodiments “gang” the first and second doublers together, and alternately angle tune the third doubler crystal, as illustrated in
In a particular embodiment, a tuning error of 30 brad from exact phase matching is allowed in the type II phase matched triplers to account for errors in crystal manufacturing.
The sign of the angular tuning error is reversed depending on the crystal's alternating-Z orientation, for example +30 and −30 μrad, as an alternate-Z tripler is an ordinary tripler rotated by 180 degrees about the beam propagation direction. The inventors have determined that a larger degree of angle tuning of alternating sign between the two tripler crystals will further increase the dynamic range of the four crystal design. The inventors have observed this tripler tuning effect in both type I/type II and type II/type II multi-crystal designs.
The implementations described herein include the phase-mismatch effect of 60 GHz of FM bandwidth imposed on the fundamental (1ω) beam, which is implemented for focal plane beam smoothing and suppression of transverse stimulated Brillouin effects in large aperture ICF lasers. This is accomplished by adding the RMS phase-mismatch from the FM phase modulation on the fundamental (1ω) to the phase-mismatch from all other sources (angle tuning, thermal tuning, crystal bulk and surface distortion, and the like) in a Square-Root of a Sum of Squares method, in both doubler and tripler crystals. The sign of the phase-mismatch is determined by the sign of the angle dependent terms.
Embodiments of the present invention also provide polarization smoothing since a predetermined portion of the beams (e.g., half of the beams) can be provided in a 3ω polarization that is aligned with a first direction (e.g., horizontal) and a second predetermined portion (e.g., the other half of the beams) can be provided in a 3ω polarization that is aligned with a second direction orthogonal to the first direction (e.g., vertical). Providing beams with orthogonal polarizations will result in polarization smoothing at the target since the speckle fields that are generated when the beams overlap on the target add incoherently. Embodiments can implement a polarization rotator (e.g., a DKDP crystal acting as a wave plate) into the doubling and/or tripling architectures or can implement a polarization rotation as a separate optical element. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.
Embodiments of the present invention provide for higher frequency converter energy efficiency that conventional designs. Table I through Table VI list frequency converter parameters and efficiencies for various embodiments of the present invention. Table I through Table IV list parameters and efficiencies for four crystal type I/type II and type II/type II frequency converter architectures. Table V and Table VI list parameters and efficiencies for two crystal type I/type II and type II/type II designs. As is evident from the tables, four crystal designs have greater efficiency in comparison with two crystal designs. As illustrated in the tables, the optimal converter design for the “total” pulse as well as for the architecture where the “foot” and “drive” portions of the pulse are amplified and converted in separated beams are provided. For a given third harmonic pulse shape, the incident pulse shape and required input energy are calculated at the input of the laser amplifier and frequency converter chain. Diffraction and beam quality are accounted for in the 1053-nm laser chain and in the frequency converter. Conversion efficiency can be optimized by changing the crystal lengths and angular tuning. While converter designs can be separately optimized for the “foot” and “drive” beams, the four crystal type II/type II designs for “foot” and “drive” beams listed in Table I use identical crystal lengths of 9 mm and achieve an overall efficiency of 74.1%. Separation of “foot” and “drive” pulses and beams is particularly effective for four-crystal type II/type II converter designs. In the type I/type II architecture, a thicker first doubler is utilized although this is not required by the present invention. It should be noted that the overall efficiency of the four crystal type II/type II architecture can be raised from 60.2% to 68.8% by implementing separate “foot” and “drive” pulse formats and beam mapping.
Table I lists frequency converter parameters for a four crystal type II/type II tripling architecture as illustrated in
Table II lists frequency converter parameters for a four crystal “thick-thin” type I/type II tripling architecture as illustrated in
Table III lists frequency converter parameters for a four crystal “thin-thick” type I/type II tripling architecture as illustrated in
Table IV lists frequency converter parameters for a four crystal “thin-thick” type II/type II tripling architecture as illustrated in
Table V lists frequency converter parameters for a two crystal type I/type II tripling architecture.
Table VI lists frequency converter parameters for a two crystal type II/type II tripling architecture.
The inventors have determined that in order to address thermal management concerns and to reduce the risk of crystal fracture, a thinner first doubler can be utilized, resulting in only a minor loss in conversion efficiency. A typical thin/thick design for a type
I/type II four crystal converter is shown in Table III, while a thin-thick design for a type II/type II converter is shown in Table IV. Further crystal thinning in all designs is possible with some loss in energy conversion efficiency, as is the possibility of adding a third doubler or tripler crystal in order to limit thermal gradients. It is believed that longitudinal thermal gradients are not expected to exceed 0.5° C. for highly deuterated KDP (>98%), which should allow the conversion efficiency for frequency tripling to remain near 70%.
In some embodiments, the distance from the relay plane to lens 320 is 640 cm and the distance from lens 320 to lens 322 is 800 cm. In the illustrated embodiment, the focal lengths of lens 320 and lens 322 sum to 2 m (i.e., F1+F2=2000 cm).
Lenses 320 and 322 provide a telescope, which can be operated under vacuum. A neutron baffle can be located at the center of the telescope to prevent propagation of neutrons to portions of the system that can sustain neutron damage.
Light from the telescope reflects off of turning mirror 330 and is reflected off of parabolic minor 340 toward the target chamber (TCC). In some embodiments, the distance from the second lens 322 to the parabolic mirror 340 is 560 cm and the distance from the parabolic mirror 340 to the target chamber is 2000 cm. In some implementations, a combination of a mirror and a Fresnel lens can be substituted for the parabolic mirror 340. The distances given above are provided merely by way of example and other optical configurations can be utilized according to embodiments of the present invention.
Embodiments of the present invention provide thermal management solutions. The inventors have determined that limiting the crystal thickness results in reductions in the risk of fracture. The temperature difference between the center and face of the crystal is limited by stress-fracture in KDP and the quality of the surface polish.
The method further includes frequency converting the doubled beam and the another portion of the input beam (e.g., the remaining portion) to a tripled beam characterized by a tripled wavelength two thirds the doubled wavelength (516). Frequency converting the doubled beam and the remaining portion of the input beam includes transmitting the doubled beam light and the remaining portion of the input beam through a second plurality of non-linear optical crystals and outputting the tripled beam. Frequency converting the doubled beam and the remaining portion of the input beam to a tripled beam can include detuning a first crystal of the second plurality of non-linear optical crystals by a third angle and detuning a second crystal of the first plurality of non-linear optical crystals by a fourth angle. The third angle is measured between a direction of beam propagation and an optic axis of the first crystal in a first direction (e.g., a positive angle) and the fourth angle is measured between the direction of beam propagation and the optic axis of the second crystal in a second direction opposite to the first direction (e.g., a negative angle) in some embodiments.
In an embodiment of the present invention, the first plurality of non-linear crystals include DKDP and the second plurality of non-linear crystals include DKDP. Additionally, a method provided by a specific embodiment includes rotating the polarization of at least the doubled beam and the remaining portion of the input beam or the tripled beam.
It should be appreciated that the specific steps illustrated in
The optical system also includes a frequency converter 660, which can include one or more frequency conversion elements as illustrated in
In order to detune the crystals as described herein, rotation and/or translation stages or integrated rotation/translation stages can be provided as elements of the frequency conversion system under the control of the control system 670.
Additionally, as discussed in relation to
It is also understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 61/411,754, filed Nov. 9, 2010, the disclosure of which is hereby incorporated by reference in its entirety for all purposes. The following PCT applications (including this one) are being filed concurrently, and the entire disclosure of the other application is incorporated by reference into this application for all purposes: Application No. PCT/US11______, filed Nov. 8, 2011 entitled “MULTI-CRYSTAL FREQUENCY TRIPLER FOR THIRD HARMONIC CONVERSION” (Client Reference No. IL-12360; Attorney Docket No. 91920-825120(006610PC)); andApplication No. PCT/US11/59688, filed Nov. 8, 2011 entitled “METHOD OF PULSE REFORMATTING FOR OPTICAL AMPLIFICATION AND FREQUENCY CONVERSION” (Client Reference No. IL-12359; Attorney Docket No. 91920-824881(006010PC)).
The United States Goverment has rights in this invention pursuant to Contract No. DE-AC52-07NA27344 between the U.S. Department of Energy and Lawrence Livermore National Security, LLC, for the operation of Lawrence Livermore National Laboratory.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US11/59777 | 11/8/2011 | WO | 00 | 3/4/2014 |
| Number | Date | Country | |
|---|---|---|---|
| 61411754 | Nov 2010 | US |
