Patent Grant
9059558
This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201210573848.4, filed on Dec. 26, 2012 in the China Intellectual Property Office. This application is also related to application entitled, “LASER”, filed Dec. 20, 2013 Ser. No. 14/137,236, “LASER”, filed Dec. 20, 2013 Ser. No. 14/137,219, “LASER”, filed Dec. 20, 2013 Ser. No. 14/137,197, and “LASER”, filed Dec. 20, 2013 Ser. No. 14/137,248. Disclosures of the above-identified applications are incorporated herein by reference.
1. Technical Field
The present disclosure relates to lasers.
2. Description of Related Art
Because of the high power levels available, a variety of lasers are frequently used in industrial applications such as cutting and welding, and in military applications such as laser weapons.
Most of the high power lasers are multi-mode lasers, and the laser beams have large divergence angle, shallow depth of focus, low stability, and high power density loss during long distance transmission.
What is needed, therefore, is to provide a laser in which the laser beam has small divergence angle, small spot size, long depth of focus, and low power density loss during long distance transmission.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments.
The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “another,” “an,” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
Similar to some prior art, the laser 10 further includes two electrodes, a water-cooled jacket, a water inlet, a water outlet, a gas reservoir, a gas tube, and other components (not shown in
The total reflective mirror 102 includes a body 1020 defining a first reflective surface 1021, and a metal film 1022 coated on the first reflective surface 1021 of the body 1020. The metal film 1022 has a second reflective surface 1023, which faces the output mirror 104. The total reflective mirror 102 further includes a microstructure 112.
The body 1020 is made of a nonmetal which is not easy to deform under heating, such as silicon, silicon oxide, and silicon carbide. In one embodiment, the body 1020 is made of silicon. The body 1020 has a diameter ranging from about 5 millimeters to about 50 millimeters. In one embodiment, the body 1020 has a diameter of 20 millimeters. The body 1020 has a thickness ranging from about 2 millimeters to about 20 millimeters. In one embodiment, the body 1020 has a thickness of 5 millimeters.
The metal film 1022 is made of a metal which has high melting point, it is difficult to be oxidized, and can produce surface plasma. In one embodiment, gold is used to make the metal film 1022. The metal film 1022 has a thickness which is greater than its skin depth. In one embodiment, the thickness of the metal film 1022 is greater than 50 nanometers. The metal film 1022 can be coated onto the first reflective surface 1021 of the body 1020 by electroplating, depositing, sputtering, spraying, or any other coating methods.
The microstructure 112 is step structure. The step structure includes a plurality of cylinders stacked with each other in series with respect to their diameters.
A height of the microstructure 112 is a sum of heights of the plurality of cylinders. Each of the plurality of cylinders in the microstructure 112 has a height ranging from about 0.5λ to about 2λ, wherein λ is the working wavelength of the laser 10. The plurality of cylinders can have a same height. In one embodiment, the same height is 0.5λ. In another embodiment, the same height is λ. The plurality of cylinders can also have different heights. A height of the microstructure 112 is in a range from about λ to about 6λ. In one embodiment, the microstructure 112 includes two cylinders stacked together, and both of the two cylinders have a height of 0.5λ. Thus, the microstructure 112 has a height of λ. The working wavelength of the laser 10 is determined by the active laser medium 108. In one embodiment, the active laser medium 108 is carbon dioxide (CO2), and the working wavelength λ is 10.6 micrometers. Therefore, the height of the microstructure 112 is in a range from about 10.6 micrometers to about 63.6 micrometers. In one embodiment, the height of the microstructure 112 is 10.6 micrometers.
While the microstructure 112 includes two cylinders stacked together, and both of the two cylinders have a height of 0.5λ, then the laser beam obtained by the laser 10 will have a relatively small divergence angle and spot size.
The microstructure 112 is a step structure, so it has different diameters in each step. Each step corresponds to each cylinder in the microstructure 112. Therefore, the diameter of each step is the diameter of each corresponding cylinder. Each cylinder in the microstructure 112 has a diameter ranging from about 0.5λ to about 2λ. While each cylinder in the microstructure 112 has a diameter ranging from about 0.5λ to about 2λ, a laser beam obtained by the laser 10 can have a relatively small spot size and a relatively low power density loss during long distance transmission. In one embodiment, the microstructure 112 includes two cylinders stacked together, wherein one cylinder has a diameter of 0.5λ, and another one has a diameter of λ. In another embodiment, the microstructure 112 includes three cylinders stacked together, wherein the first hole has a diameter of 0.5λ, the second one has a diameter of λ, and the third one has a diameter of 1.5λ.
While the height and the diameter in each step of the microstructure 112 are all in a range from about 0.5λ to about 2λ, then the laser beam obtained by the laser 10 will have a relatively small divergence angle and spot size, and will have a relatively low power density loss during long distance transmission.
The output mirror 104 is a flat mirror. A diameter can be same as the body 1020 of the total reflective mirror 102. In one embodiment, the diameter of the output mirror 104 is 20 millimeters. The output mirror 104 is a partial reflective mirror. A reflectivity of the output mirror 104 ranges from about 25% to about 55%. The output mirror 104 is made of germanium, zinc selenide, or gallium arsenide. In one embodiment, the output mirror 104 is made of zinc selenide.
The discharge lamp 106 is a quartz glass tube. The discharge lamp 106 has a diameter smaller than that of the output mirror 104. In one embodiment, the diameter of the discharge lamp 106 is in a range from about 2 millimeters to about 10 millimeters. In another embodiment, the diameter of the discharge lamp 106 is in a range from about 5 millimeters to about 6 millimeters.
The active laser medium 108 can be gas, such as CO2, helium (He), neon (Ne), nitrogen (N2), and carbon oxide (CO). The active laser medium 108 can also be solid, liquid, or semi-conductor. In one embodiment, the active laser medium 108 is CO2.
The resonant cavity 110 has a length of about 400 millimeters to about 800 millimeters. In one embodiment, the length of the resonant cavity 110 ranges from about 500 millimeters to about 600 millimeters. In another embodiment, the length of the resonant cavity 110 is 600 millimeters.
Each of the plurality of microstructures 212 is a step structure. The step structure includes a plurality of cylinders stacked with each other in series with respect to their diameters.
The shape, structure, and size of the microstructure 212 are all the same as that of the microstructure 112.
There is an interval between each two adjacent microstructures 212. Each interval has a size ranging from about 0.5λ to about 2λ. In one embodiment, each interval has a same size. In another embodiment, the same size of all the intervals is λ. When the active laser medium 208 is CO2, each interval has a size ranging from about 5.3 micrometers to about 21.2 micrometers.
The other components of the laser 20 are all the same as that of the laser 10.
Compared with the laser 10 having one microstructure 112, the laser 20 has a plurality of microstructures 212; additionally, each interval between each two adjacent microstructures 212 has a size ranging from about 0.5λ, to about 2λ, therefore, the surface plasma resonance produced in the resonant cavity 210 is more remarkable. A laser beam which has a long depth of focus, and low power density loss during long distance transmission can then be obtained.
The laser beam obtained by the laser 10 or 20 in present disclosure has a high quality beam, a long depth of focus, and a high power density in the beam center. Therefore, the laser beam can be easily applied in cutting or welding, especially in long distance transmission or commutation.
It is to be understood that the above-described embodiment is intended to illustrate rather than limit the disclosure. Variations may be made to the embodiment without departing from the spirit of the disclosure as claimed. The above-described embodiments are intended to illustrate the scope of the disclosure and not restricted to the scope of the disclosure.
It is also to be understood that the above description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012 1 0573848 | Dec 2012 | CN | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20020105993 | Tang | Aug 2002 | A1 |
| 20090110021 | Conway et al. | Apr 2009 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20140294033 A1 | Oct 2014 | US |
