High efficiency laser-sustained plasma light source
地域：
CA
CA Milpitas
摘要
A system for generating laser sustained broadband light includes a pump source configured to generate a pumping beam, a gas containment structure for containing a gas and a multi-pass optical assembly. The multi-pass optical assembly includes one or more optical elements configured to perform a plurality of passes of the pumping beam through a portion of the gas to sustain a broadband-light-emitting plasma. The one or more optical elements are arranged to collect an unabsorbed portion of the pumping beam transmitted through the plasma and direct the collected unabsorbed portion of the pumping beam back into the portion of the gas.
說明書
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The present application is related to and claims the benefit of the earliest available effective filing date(s) from the following listed application(s) (the “Related Applications”) (e.g., claims earliest available priority dates for other than provisional patent applications or claims benefits under 35 USC § 119(e) for provisional patent applications, for any and all parent, grandparent, great-grandparent, etc. applications of the Related Application(s)).
For purposes of the USPTO extra-statutory requirements, the present application constitutes a regular (non-provisional) patent application of U.S. Provisional Patent Application entitled MULTIPASS LASER-SUSTAINED PLASMA PUMP GEOMETRIES, naming Ilya Bezel, Anatoly Shchemelinin Eugene Shifrin and Matthew Derstine as inventors, filed Jun. 22, 2015, Application Ser. No. 62/183,069, which is incorporated herein by reference in the entirety.
For purposes of the USPTO extra-statutory requirements, the present application constitutes a regular (non-provisional) patent application of United States Provisional Patent Application entitled OPTICAL WAFER INSPECTOR, naming Matthew Derstine and Ilya Bezel as inventors, filed Feb. 3, 2016, Application Ser. No. 62/290,593, which is incorporated herein by reference in the entirety.
The present invention generally relates to laser-sustained plasma light source, and, more particularly, to a multi-pass laser-sustained plasma light source.
權利要求
What is claimed:1. A system comprising:a pump source configured to generate a pumping beam; a gas containment structure for containing a gas; and a multi-pass optical assembly, wherein the multi-pass optical assembly includes one or more optical elements configured to perform a plurality of passes of the pumping beam through a portion of the gas to sustain a broadband-light-emitting plasma, wherein the one or more optical elements are arranged to collect an unabsorbed portion of the pumping beam transmitted through the plasma and direct the collected unabsorbed portion of the pumping beam back into the portion of the gas, wherein the one or more optical elements include a plurality of converging mirrors, wherein the plurality of converging mirrors are arranged such that the numerical aperture of the pumping beam during a subsequent pass through the plasma is lower than the numerical aperture of the pumping beam during a first pass through the plasma to offset the absorption of the pumping during the successive passes of the pumping beam through the plasma and produce an intensity distribution of the subsequent pass substantially the same as an intensity distribution of the first pass. 2. The system of claim 1 , wherein the one or more optical elements comprise:a first optical element; and at least an additional optical element, wherein the first optical element and the at least an additional optical element are arranged to collect an unabsorbed portion of the pumping beam and direct the collected unabsorbed portion of the pumping beam into the portion of the gas. 3. The system of claim 1 , wherein the one or more optical elements comprise:a reflective surface having a first portion and at least an additional portion, wherein the first portion and the at least an additional portion are arranged to collect an unabsorbed portion of the pumping beam and redirect the collected unabsorbed portion of the pumping beam into the portion of the gas. 4. The system of claim 1 , wherein the one or more optical elements comprise:at least one of one or more reflective optical elements or one or more transmissive optical elements. 5. The system of claim 4 , wherein the one or more reflective optical elements comprise:at least one of an elliptical mirror, a parabolic mirror, a spherical mirror or a flat mirror. 6. The system of claim 4 , wherein the one or more reflective optical elements are arranged off-axis relative to the optical axis defined by an incident pass of the pumping beam from the illumination source. 7. The system of claim 4 , wherein the one or more reflective optical elements comprise:one or more mirrors selectively transmissive of one or more selected wavelengths of light. 8. The system of claim 4 , wherein the one or more reflective optical elements comprise:one or more mirrors selectively absorptive of one or more selected wavelengths of light. 9. The system of claim 4 , wherein the one or more transmissive optical elements comprise:one or more lenses. 10. The system of claim 1 , wherein the one or more optical elements comprise:a first set of optical elements associated with a first pass of the pumping beam through the plasma; and an additional set of optical elements associated with an additional pass of the pumping beam through the plasma, wherein the first set of optical elements and the additional set of optical elements are arranged such that illumination of the additional pass of the pumping beam traverses a region between one or more portions of the first set of optical elements. 11. The system of claim 1 , wherein the one or more optical elements are configured to control a shape of the plasma by controlling a position of each focal point of each pass of the pumping beam. 12. The system of claim 11 , wherein the one or more optical elements are arranged such that the focal point of each pass of the pumping beam substantially overlap to form a spot. 13. The system of claim 11 , wherein the one or more optical elements are arranged to displace a focal point of a first pass of the pumping beam relative to a focal point of at least an additional pass of the pumping beam so as to form an elongated plasma. 14. The system of claim 1 , wherein the one or more optical elements comprise:at least one retro-reflector assembly. 15. The system of claim 1 , wherein the one or more optical elements comprise:at least one resonator assembly. 16. The system of claim 1 , further comprising:one or more wavefront sensors arranged to measure aberration caused during one or more passes of the pumping beam through the portion of the gas. 17. The system of claim 16 , wherein the one or more optical elements comprise:an adaptive optical element responsive to the one or more wavefront sensors. 18. The system of claim 1 , wherein the one or more optical elements are further configured to collect and direct at least a portion of broadband radiation emitted by the plasma back to the plasma. 19. The system of claim 1 , further comprising:one or more collection optical elements configured to direct at least a portion of broadband radiation emitted by the plasma to one or more downstream optical elements. 20. The system of claim 19 , wherein the one or more collection optical elements are configured to collect and direct at least a portion of broadband radiation emitted by the plasma back to the plasma. 21. The system of claim 1 , wherein the broadband radiation emitted by the plasma includes at least one of extreme ultraviolet radiation, vacuum ultraviolet radiation, deep ultraviolet radiation, ultraviolet radiation or visible radiation. 22. The system of claim 1 , wherein the gas containment element comprises:a plasma bulb for containing the gas. 23. The system of claim 1 , wherein the gas containment element comprises:a plasma cell for containing the gas. 24. The system of claim 1 , wherein the gas containment element comprises:a chamber for containing the gas. 25. The system of claim 1 , wherein the illumination source comprises:one or more lasers. 26. The system of claim 25 , wherein the one or more lasers comprise:at least one of one or more infrared lasers, one or more visible lasers or one or more ultraviolet lasers. 27. The system of claim 25 , wherein the one or more lasers comprise:at least one of a diode laser, a disk laser or a fiber laser. 28. The system of claim 25 , wherein the one or more lasers comprise:at least one of a narrowband laser or a broadband laser. 29. The system of claim 25 , wherein the one or more lasers are configured to operate in at least one of a continuous wave (CW) mode, a pulsed mode or a modulated mode. 30. The system of claim 1 , wherein the gas comprises:at least one of an inert gas, a non-inert gas and a mixture of two or more gases. 31. A system comprising:a pump source configured to generate a pumping beam; a gas containment structure for containing a gas; and a multi-pass optical assembly, wherein the multi-pass optical assembly includes one or more optical elements configured to perform a plurality of passes of the pumping beam through a portion of the gas to sustain a broadband-light-emitting plasma, wherein the one or more optical elements are arranged to collect an unabsorbed portion of the pumping beam transmitted through the plasma and direct the collected unabsorbed portion of the pumping beam back into the portion of the gas, wherein the one or more optical elements include a plurality of converging mirrors, wherein the plurality of converging mirrors are arranged in an optical threading configuration, wherein one or more optical elements of a higher-order pass of the multi-pass optical assembly are configured to direct the pumping beam from the higher-order pass between two or more optical elements of a lower-order pass of the multi-pass optical assembly, wherein the one or more optical elements are arranged to produce an intensity distribution of a subsequent pass substantially the same as an intensity distribution of the first pass.
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