IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0658906
(2003-09-10)
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발명자
/ 주소 |
- Kulp,Thomas Jan
- Kliner,Dahv A. V.
- Sommers,Ricky
- Goers,Uta Barbara
- Armstrong,Karla M.
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출원인 / 주소 |
- Sandia National Laboratories
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인용정보 |
피인용 횟수 :
25 인용 특허 :
21 |
초록
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The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorptio
The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.
대표청구항
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What is claimed is: 1. A light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising: a light-generating device producing light at more than one wavelength; an optical fiber amplifier having at least one pump laser with an output and a gain medium, wh
What is claimed is: 1. A light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising: a light-generating device producing light at more than one wavelength; an optical fiber amplifier having at least one pump laser with an output and a gain medium, where each of said at least one pump laser is an air-cooled pump laser having an operating temperature at an ambient temperature, where said optical fiber amplifier accepts light from said light generating device and produces amplified light at said more than one wavelength, and where the absorption of the output of said pump laser by said gain medium varies by no more than about 10% over a range of ambient temperatures of from about 0 C to about 40 C; and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength. 2. The light source of claim 1, wherein said light-generating device produces continuous-wave light. 3. The light source of claim 1, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 4. The light source of claim 1, wherein said light-generating device is a multi-longitudinal-mode laser. 5. The light source of claim 4, wherein said laser is a Nd:YAG laser. 6. The light source of claim 1, wherein said light-generating device is laser diode. 7. The light source of claim 1, wherein said light-generating device is fiber diode. 8. The light source of claim 1, wherein said light-generating device includes two or more light-generating devices; and further including a switch to select light from one of said two or more light-generating devices for acceptance by said optical fiber amplifier. 9. The light source of claim 1, wherein said light-generating device produces wavelength tunable light. 10. The light source of claim 9, wherein said wavelength tunable light is tunable between two wavelengths. 11. The light source of claim 1, wherein said optical fiber amplifier is a Yb-doped, tapered fiber amplifier. 12. The light source of claim 11, wherein said pump laser wavelength is near 915 nm. 13. The light source of claim 1, wherein said OPO has a cavity that tunably adjusts said wavelength output. 14. The light source of claim 1, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 15. The light source of claim 1, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 16. The light source of claim 1, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 17. A light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising: a light-generating device producing light at more than one wavelength; an optical fiber amplifier to accept light from said light-generating device and produce amplified light at said more than one wavelength, wherein said optical fiber amplifier is a Yb-doped, tapered optical fiber amplifier, wherein said optical fiber amplifier includes at least one pump laser and a gain medium, and wherein each of said at least one pump laser is an air-cooled pump laser having an operating temperature at an ambient temperature; and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength. 18. The light source of claim 17, wherein said air-cooled pump laser has an operating temperature at an ambient temperature, and wherein the absorption of the output of said pump laser by said gain medium varies by no more than about 10% over a range of said ambient temperatures of from about 0 C to about 40 C. 19. The light source of claim 17, wherein said light-generating device produces continuous-wave light. 20. The light source of claim 17, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 21. The light source of claim 17, wherein said light-generating device is a multi-longitudinal-mode laser. 22. The light source of claim 21, wherein said laser is a Nd:YAG laser. 23. The light source of claim 17, wherein said light-generating device is a laser diode. 24. The light source of claim 17, wherein said light-generating device is a fiber diode. 25. The light source of claim 17, wherein said light-generating device includes two or more light-generating devices; and further including switch to select light from one of said two or more light-generating devices for acceptance by said optical fiber amplifier. 26. The light source of claim 17, wherein said light-generating device produces wavelength tunable light. 27. The light source of claim 26, wherein said wavelength tunable light is tunable between two wavelengths. 28. The light source of claim 17, wherein said optical fiber amplifier includes at least one pump laser with an output of near 915 nm. 29. The light source of claim 17, wherein said OPO has a cavity that tunably adjusts said wavelength output. 30. The light source of claim 17, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 31. The light source of claim 17, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 32. The light source of claim 17, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 33. A light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising: two or more light-generating devices each producing light at more than one wavelength; a switch to select light from one of said two or more light-generating devices; an optical fiber amplifier to accept said selected light and produce amplified light at the more than one wavelength of said selected light; and an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength. 34. The light source of claim 33, wherein said light-generating device produces continuous-wave light. 35. The light source of claim 33, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 36. The light source of claim 33, wherein at least one of said two or more light-generating devices is a multi-mode laser. 37. The light source of claim 36, wherein said laser is a Nd:YAG laser. 38. The light source of claim 33, wherein at least one of said two or more light-generating devices is a laser diode. 39. The light source of claim 33, wherein at least one of said two or more light-generating devices produces tunable light. 40. The light source of claim 33, wherein said optical fiber amplifier is a Yb-doped, tapered fiber amplifier. 41. The light source of claim 33, wherein said optical fiber amplifier includes at least one pump laser with an output of near 915 nm. 42. The light source of claim 33, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 43. The light source of claim 33, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 44. The light source of claim 33, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 45. A light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising: a diode-pumped fiber laser producing an output of light at more than one wavelength, where said diode-pumped fiber laser is an air-cooled laser having an operating temperature at an ambient temperature, and where said output varies with temperature; and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said output and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength; where said diode-pumped fiber laser is sufficiently air-cooled to provide an output hat varies by no more than 10% over an ambient temperature range of from about 0 C to about 40 C. 46. A backscatter absorption gas imaging system operating at an ambient temperature for imaging a gas between the system and a scene, comprising: a light source to generate an output for illuminating said scene, including a light-generating device producing light at more than one wavelength, an optical fiber amplifier having at least one pump laser with an output and a gain medium, where each of said at least one pump laser is an air-cooled pump laser having an operating temperature at said ambient temperature, where said optical fiber amplifier accepts light from said light generating device and produces amplified light at said more than one wavelength, and where the absorption of the output of said pump laser by said gain medium varies by no more than about 10% over an ambient temperature range of from about 0 C to about 40 C; and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength; and a camera responsive to backscattered illumination by said light source. 47. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device produces continuous-wave light. 48. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 49. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device is a multi-longitudinal-mode laser. 50. The backscatter absorption gas imaging system 49, wherein said laser is a Nd:YAG laser. 51. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device is laser diode. 52. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device is fiber diode. 53. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device includes two or more light-generating devices; and further including a switch to select light from one of said two or more light-generating devices for acceptance by said optical fiber amplifier. 54. The backscatter absorption gas imaging system of claim 46, wherein said light-generating device produces wavelength tunable light. 55. The backscatter absorption gas imaging system of claim 54, wherein said wavelength tunable light is tunable between two wavelengths. 56. The backscatter absorption gas imaging system of claim 46, wherein said optical fiber amplifier is a Yb-doped, tapered fiber amplifier. 57. The backscatter absorption gas imaging system of claim 56, wherein said pump laser wavelength is near 915 nm. 58. The backscatter absorption gas imaging system of claim 46, wherein said OPO has a cavity that tunably adjusts said wavelength output. 59. The backscatter absorption gas imaging system of claim 46, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 60. The backscatter absorption gas imaging system of claim 46, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 61. The backscatter absorption gas imaging system of claim 46, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 62. A backscatter absorption gas imaging system operating at an ambient temperature for imaging a gas between the system and a scene, comprising: a light source to generate an output for illuminating said scene, including a light-generating device producing light at more than one wavelength, an optical fiber amplifier to accept light from said light-generating device and produce amplified light at said more than one wavelength, wherein said optical fiber amplifier is a Yb-doped, tapered optical fiber amplifier, wherein said optical fiber amplifier includes at least one pump laser, and wherein each of said at least one pump laser is an air-cooled pump laser, and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength; and a camera responsive to backscattered illumination by said light source. 63. The backscatter absorption gas imaging system of claim 62, wherein said air-cooled pump laser has an operating temperature at an ambient temperature, and wherein the absorption of the output of said pump laser by said gain medium varies by no more than about 10% over an ambient temperature range of from about 0 C to about 40 C. 64. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device produces continuous-wave light. 65. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 66. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device is a multi-longitudinal-mode laser. 67. The backscatter absorption gas imaging system of claim 66, wherein said laser is a Nd:YAG laser. 68. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device is a laser diode. 69. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device is a fiber diode. 70. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device includes two or more light-generating devices; and further including a switch to select light from one of said two or more light-generating devices for acceptance by said optical fiber amplifier. 71. The backscatter absorption gas imaging system of claim 62, wherein said light-generating device produces wavelength tunable light. 72. The backscatter absorption gas imaging system of claim 71, wherein said wavelength tunable light is tunable between two wavelengths. 73. The backscatter absorption gas imaging system of claim 62, wherein said optical fiber amplifier includes at least one pump laser with an output of near 915 nm. 74. The backscatter absorption gas imaging system of claim 62, wherein said OPO has a cavity that tunably adjusts said wavelength output. 75. The light source of claim 62, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 76. The backscatter absorption gas imaging system of claim 62, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 77. The backscatter absorption gas imaging system of claim 62, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 78. A backscatter absorption gas imaging system for imaging a gas between the system and a scene, comprising: a light source to generate an output for illuminating said scene, including two or more light-generating devices each producing continuous-wave light at more than one wavelength; a switch to select light from one of said two or more light-generating devices; an optical fiber amplifier to accept said selected light and produce amplified light at the more than one wavelength of said selected light; and an optical parametric oscillator (OPO) to accept said amplified light and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength; and a camera responsive to backscattered illumination by said light source. 79. The backscatter absorption gas imaging system of claim 78, wherein said light-generating device produces continuous-wave light. 80. The light source of claim 78, wherein said light-generating device produces quasi-continuous-wave light, where said quasi-continuous-wave light has a repetition rate greater than about 10 kHz. 81. The light source of claim 78, wherein at least one of said two or more light-generating devices is a multi-mode laser. 82. The light source of claim 81, wherein said laser is a Nd:YAG laser. 83. The light source of claim 78, wherein at least one of said two or more light-generating devices is a laser diode. 84. The light source of claim 78, wherein at least one of said two or more light-generating devices produces tunable light. 85. The light source of claim 78, wherein said optical fiber amplifier is a Yb-doped, tapered fiber amplifier. 86. The light source of claim 78, wherein said optical fiber amplifier includes at least one pump laser with an output of near 915 nm. 87. The light source of claim 78, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is singly resonant at the wavelength of either said signal beam or of said idler beam. 88. The light source of claim 78, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, and wherein said OPO is doubly resonant at the wavelength of said signal beam and at the wavelength of said idler beam. 89. The light source of claim 78, wherein said OPO, having accepted said amplified light, generates a signal beam and an idler beam, further including optics to provide said idler beam as said adjustable wavelength output. 90. A backscatter absorption gas imaging system for imaging a gas between the system and a scene, comprising: a light source to provide illumination for a scene for a backscatter absorption gas imaging system comprising a diode-pumped fiber laser producing an output of light at more than one wavelength, where said diode-pumped fiber laser is an air-cooled laser, and where said output varies with temperature, and a nonlinear frequency converter including an optical parametric oscillator (OPO) to accept said output and generate an output of the light source at wavelengths shifted from and corresponding to each of said more than one wavelength; and a camera responsive to backscattered illumination by said light source, where said diode-pumped fiber laser is sufficiently air-cooled to provide an output that varies by no more than 10% over an ambient temperature range of from about 0 C to about 40 C.
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