System and method for separation of pump light and collected light in a laser pumped light source

Patent metadata

Field	Value
Publication number	US-9709811-B2
Application number	US-201414459095-A
Country	US
Kind code	B2
Filing date	Aug 13, 2014
Priority date	Aug 14, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A system for separating plasma pumping light and collected broadband light includes a pump source configured to generate pumping illumination including at least a first wavelength, a gas containment element for containing a volume of gas, a collector configured to focus the pumping illumination from the pumping source into the volume of gas to generate a plasma within the volume of gas, wherein the plasma emits broadband radiation including at least a second wavelength and an illumination separation prism element positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the emitted broadband radiation including at least a second wavelength emitted from the plasma.

First claim

What is claimed:

1. A system for separating pump light and collected light in a laser pumped light source comprising:
a pump source configured to generate pumping illumination including at least a first wavelength;
a gas containment element for containing a volume of gas;
a collector configured to focus the pumping illumination from the pumping source into the volume of gas to generate a plasma within the volume of gas, wherein the plasma emits broadband radiation including at least a second wavelength; and
one or more illumination separation prism elements positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the emitted broadband radiation including at least a second wavelength emitted from the plasma, wherein the one or more separation prism elements are positioned such that the pumping illumination including the first wavelength enters the one or more illumination separation prism elements at a first face and broadband radiation including the at least the second wavelength enters the one or more illumination separation prism elements at a second face different from the first face.

2. The system of claim 1 , wherein the one or more illumination separation prism elements comprise:
one or more total internal reflection elements positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the broadband radiation including at least the second wavelength emitted from the plasma.

3. The system of claim 2 , wherein the one or more total internal reflection elements is formed from a selected material and arranged relative to the pump source and the generated plasma in order to establish total internal reflection to the plasma illumination and transparency to the pump illumination.

4. The system of claim 3 , wherein the plasma illumination undergoes total internal reflection at a first surface within the one or more total internal reflection elements and exits the one or more total internal reflection elements at a second face.

5. The system of claim 2 , the one or more total internal reflection elements comprises:
a plurality of total internal reflection elements.

6. The system of claim 1 , wherein the one or more illumination separation prism elements comprise:
one or more dispersion elements positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the broadband radiation including at least the second wavelength emitted from the plasma.

7. The system of claim 6 , wherein the one or more dispersion elements is formed from a material and a selected material and arranged relative to the pump source and the generated plasma in order to separate the pump illumination and plasma illumination by deflecting the plasma illumination from an initial direction via refraction.

8. The system of claim 6 , further comprising:
one or more collimating optics configured to collimate at least one of the pump illumination and the plasma illumination prior to incidence on the one or more dispersion elements.

9. The system of claim 6 , further comprising:
one or more recombination optics configured to combine plasma illumination emanating from the one or more dispersion elements.

10. The system of claim 6 , further comprising:
one or more additional dispersion elements configured to compensate for dispersion caused by the one or more dispersion elements.

11. The system of claim 6 , the one or more dispersion elements comprises:
a plurality of dispersion elements.

12. The system of claim 1 , wherein the one or more illumination separation prism elements comprise:
one or more evanescent field coupling elements positioned between a reflective surface of the collector and the pump source and arranged to spatially separate the pumping illumination including the first wavelength and the broadband radiation including at least the second wavelength emitted from the plasma.

13. The system of claim 12 , wherein the one or more evanescent field coupling elements comprise:
a first sub-element;
a second sub-element positioned proximate to the first sub-element to form a gap between the first sub-element and the second sub-element having a selected distance, wherein the first sub-element and the second sub-element are arranged to transmit at least a portion of the pumping illumination including the first wavelength and reflect at least a portion of the broadband radiation including at least the second wavelength emitted by the plasma.

14. The system of claim 13 , wherein the first sub-elements comprises:
a prism.

15. The system of claim 14 , wherein the second sub-elements comprises:
at least one of a prism and a plate coated with at least one of an infrared coating or an anti-reflective coating.

16. The system of claim 13 , wherein the gap between first sub-element and the second sub-element contains a coating having a low refractive index.

17. The system of claim 1 , wherein one or more surface of the one or more illumination separation prism elements is coated with at least one of an infrared coating and an anti-reflective coating in order to reduce reflection of at least one of the pumping illumination and the broadband illumination at the one or more surfaces.

18. The system of claim 1 , wherein the one or more illumination separation prism elements are formed from at least one of calcium fluoride, magnesium fluoride, crystalline quartz and sapphire.

19. The system of claim 1 , wherein the broadband radiation emitted by the plasma includes at least one of vacuum ultraviolet radiation, deep ultraviolet radiation, ultraviolet radiation and visible radiation.

20. The system of claim 1 , wherein the gas containment element comprises:
a plasma bulb for containing the gas.

21. The system of claim 1 , wherein the gas containment element comprises:
a plasma cell for containing the gas.

22. The system of claim 21 , wherein the plasma cell comprises:
a transmission element; and
one or more flanges disposed at one or more ends of the transmission element for containing the gas.

23. The system of claim 1 , wherein a transmitting portion of the gas containment element is formed from at least one of calcium fluoride, magnesium fluoride, crystalline quartz, sapphire and fused silica.

24. The system of claim 1 , wherein a transmitting portion of the gas containment element is at least partially transparent to at least one of vacuum ultraviolet radiation, deep ultraviolet radiation, ultraviolet radiation and visible radiation emitted by the plasma.

25. The system of claim 1 , wherein the collector comprises:
an ellipsoid-shaped collector.

26. The system of claim 1 , wherein the illumination source comprises:
one or more lasers.

27. The system of claim 26 , wherein the one or more lasers comprise:
at least one of one or more infrared lasers, one or more visible lasers and one or more ultraviolet lasers.

28. The system of claim 26 , wherein the one or more lasers comprise:
at least one of a diode laser, a continuous wave laser, or a broadband laser.

29. The system of claim 1 , wherein the gas comprises:
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Assignees

• Kla Tencor Corp

Inventors

• Shchemelinin Anatoly
• Bezel Ilya
• Panzer Matthew
• Shifrin Eugene

Classifications

• G02B27/1006 Primary

  for splitting or combining different wavelengths (G02B27/1086, G02B27/141 take precedence) · CPC title