2μm激光器频率锁定技术的研究
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摘要
以2μm固体激光器作为发射机的成像雷达、相干多普勒风速监测雷达和大气水分差分吸收雷达是激光雷达研究的重点之一。雷达光源通常要求单纵模、高功率输出。种子激光器(也称为主激光器)提供低功率、窄线宽、单频、稳定的激光输出,从激光器将其放大,获得高功率、窄线宽、单模运行、稳定频率的激光输出。所以实现2μm的注入锁频,为激光雷达提供光源是该课题的主要研究意义。
理论上,通过注入锁定的经典理论模型分析了注入锁定理论。实现注入锁频,必须满足主、从激光器的模式匹配;同时对主激光器必须满足一定的注入功率、单频、稳定、窄线宽等。实现注入锁频后,环形腔能量转换效率接近于1,光谱纯度变纯。
实验上,首先由于种子光的输出特性直接影响到锁频的实现,所以对种子光进行了若干研究。实验中,采用低温Tm,Ho:YLF微片激光器获得稳定、基横模、单纵模2067nm激光输出,输出功率可达32.8mW。其次着重讨论了种子模与环形腔模式匹配的问题。主从激光器模式匹配与否直接影响锁频的实现及锁频率。对偏角注入和偏轴注入分别进行了研究,实验发现,偏轴注入是影响模式匹配的主要因素。再次,设计了环形功率腔,环形腔仍采用Tm,Ho:YLF晶体作为工作物质,这样易于模式诱导,完成了注入锁频的实验研究。通过实验可以明显地看到注入锁频的实际效果。环形腔单向输出;脉冲建立时间缩短500ns;脉冲宽度变窄,在环形腔输出功率2mJ时,脉宽由未锁定时的219.2ns变为锁定情况下的156.3ns;脉冲输出变稳等,并分析了产生上述现象的原因。在相同的重复频率下,输出脉冲能量随泵浦能量的增加而增加,脉冲宽度随泵浦能量的增加变窄。利用F-P干涉仪慢扫描法,更为直观的看到了注入种子对环形腔的模式诱导作用。
The 2-micron laser has particular characters. It is the preferred lamp-house of the imaging LIDAR ,the coherent Doppler LIDAR for wind sensing and the DIAL for measuring change of the depth and the temperature of earthly atmosphere. The lamp-house of LIDAR are always composed of one power oscillator and one seed laser. Seed laser is also called master oscillator. It is provided with low power, narrow linewidth, single frequency, stable laser. Inject seed laser to a power oscillator to obtain high power, narrow linewidth, single-mode, stable frequency laser. In this paper, we use the laser diode pumped Tm,Ho:YLF to achieve injection-locking laser of 2-micron .
Theoretically, this paper analyzes the theory of injection-locking. To achieve injection-locking laser, the mode of seed laser and power oscillator must match. The seed laser must be single frequency, stable, narrow linewidth and sufficing some power. Then, analyze the hallmark of spectrum and so on.
Experimentally, firstly, in view of the important of seed laser, at low temperature, we achieve perfect seed laser by using Tm,Ho:YLF microchip. The seed laser is stable, single-mode, 2067nm. The output power is up to 32.8mW. Secondly, we research the modes matching. It directly effects the frequency-locked. Both departure from angle and departure from axis can take difficult to the injection-locking. But the latter is more important. Thirdly, we design ring laser to carry out frequency-locked. When inject the seed source into the slaver oscillator through the output coupler, and unidirectional operation can be induced. The time of pulse build-up is shorter. The pulse width is narrower. The output pulse is more stable. Discuss the pulse energy and pulse width change by pump power. Making use of F-P interferometer method, we see more clearly about the mode inducing from seed laser to slaver oscillator.
理论上,通过注入锁定的经典理论模型分析了注入锁定理论。实现注入锁频,必须满足主、从激光器的模式匹配;同时对主激光器必须满足一定的注入功率、单频、稳定、窄线宽等。实现注入锁频后,环形腔能量转换效率接近于1,光谱纯度变纯。
实验上,首先由于种子光的输出特性直接影响到锁频的实现,所以对种子光进行了若干研究。实验中,采用低温Tm,Ho:YLF微片激光器获得稳定、基横模、单纵模2067nm激光输出,输出功率可达32.8mW。其次着重讨论了种子模与环形腔模式匹配的问题。主从激光器模式匹配与否直接影响锁频的实现及锁频率。对偏角注入和偏轴注入分别进行了研究,实验发现,偏轴注入是影响模式匹配的主要因素。再次,设计了环形功率腔,环形腔仍采用Tm,Ho:YLF晶体作为工作物质,这样易于模式诱导,完成了注入锁频的实验研究。通过实验可以明显地看到注入锁频的实际效果。环形腔单向输出;脉冲建立时间缩短500ns;脉冲宽度变窄,在环形腔输出功率2mJ时,脉宽由未锁定时的219.2ns变为锁定情况下的156.3ns;脉冲输出变稳等,并分析了产生上述现象的原因。在相同的重复频率下,输出脉冲能量随泵浦能量的增加而增加,脉冲宽度随泵浦能量的增加变窄。利用F-P干涉仪慢扫描法,更为直观的看到了注入种子对环形腔的模式诱导作用。
The 2-micron laser has particular characters. It is the preferred lamp-house of the imaging LIDAR ,the coherent Doppler LIDAR for wind sensing and the DIAL for measuring change of the depth and the temperature of earthly atmosphere. The lamp-house of LIDAR are always composed of one power oscillator and one seed laser. Seed laser is also called master oscillator. It is provided with low power, narrow linewidth, single frequency, stable laser. Inject seed laser to a power oscillator to obtain high power, narrow linewidth, single-mode, stable frequency laser. In this paper, we use the laser diode pumped Tm,Ho:YLF to achieve injection-locking laser of 2-micron .
Theoretically, this paper analyzes the theory of injection-locking. To achieve injection-locking laser, the mode of seed laser and power oscillator must match. The seed laser must be single frequency, stable, narrow linewidth and sufficing some power. Then, analyze the hallmark of spectrum and so on.
Experimentally, firstly, in view of the important of seed laser, at low temperature, we achieve perfect seed laser by using Tm,Ho:YLF microchip. The seed laser is stable, single-mode, 2067nm. The output power is up to 32.8mW. Secondly, we research the modes matching. It directly effects the frequency-locked. Both departure from angle and departure from axis can take difficult to the injection-locking. But the latter is more important. Thirdly, we design ring laser to carry out frequency-locked. When inject the seed source into the slaver oscillator through the output coupler, and unidirectional operation can be induced. The time of pulse build-up is shorter. The pulse width is narrower. The output pulse is more stable. Discuss the pulse energy and pulse width change by pump power. Making use of F-P interferometer method, we see more clearly about the mode inducing from seed laser to slaver oscillator.
引文
1. Barnes N P, Barnes J C. Injection seeding I: theory [J].I EEE Journal of Quantum Electronics.1993,29 (10):2670-2683.
2. Park Y K, Giuliani G, Byer R L. Stable single-axial-mode operation of an unstable-resonator Nd:YAG oscillator by injection locking[J].Optics Letters.1980,5(3):96 -98.
3. Alcock A J, Corkum P B, James D J, et al. Selection of single, mode locked CO2 laser pulses by semiconductor reflection switching[J].Optics Comm.1976, 18:543-545.
4. Bigio I J, Slatkine M. Injection2locking unstable resonator excimer lasers[J] .IEEE Journal of Quantum Elect ronics.1983,19 (9):426-1436.
5. Zayhowski J J, Mooradian A Frequency-modulated Nd:YAG microchip lasers[J]. Optics Letters.1989:14(12) 618-620.
6.张国威.可调谐激光技术.国防工业大学出版社.北京. 2002:248-249.
7. G. J. Koch, John,P. Deyst, Mark. E. Storm. Single-frequency Lasing of Monolithic Ho, Tm: YLF. Opt. Lett. 1993, 18, (15): 1235-1237.
8. G. J. Koch, R.E.Davis, A.N.Dharamsi, M.Petros and J.C. Mc Carthy. Differential Absorption Measurements of Atmospheric Water Vapor with A Coherent Lidar at 2050.532nm.Proceedings of Tenth Biennial Coherent Laser Radar Technology and Applications Conference.1999:69-71.
9. G. J. Koch, A. N. Dharamsi, C. M. Fitzgerald and J. C. Mc Carthy. Frequency Stabilization of A Ho, Tm:YLF Laser to Absorption Lines Of Carbon Dioxide. Appl Opt. 2000, 39(21):3664-3669.
10. G..J.Koch,B.W.Barnes,M.Petros,J.Y.Beyon,F.AmzajerdianJ.Yu,R.E.Davis,S.Cohe-rent Differential Absorption LIDAR Measurements of CO2.Appl.Opt. 2004, 43(26): 5092-5099.
11. G..J.Koch, M.Petros, J.Yu, and U.N.Singh. Precise Wavelength Control of a Single-frequency Pulsed Ho:Tm:YLF Laser. App.Opt.2002, 41(9):1718-1721.
12. U. N. Singh, J. Yu, M.Petros, N. P. Barnes, J. A. Williams-Byrd, G. E. Lockard, And E. A.modlin. Injection-seeded, Room-temperature, Diode-pumped Ho, Tm:YLF Laser with Output Energy of 600mJ at 10Hz. OSATrends in Optics And Photonics Series. 1998,19:194-196.
13. G. J. Koch, R. E. Davis, A. N. Dharamsi, M. Petros and J. C. Mc Carthy. Differential Absorption Measurements of Atmospheric Water Vapor with A Coherent LIDAR at 2050.532nm. Proceedings of Tenth Biennial Coherent Laser Radar Technology and Applications Conference. 1999:69-71.
14. American National Standard for the Safe Use of Lasers Z136.1-1992. American National Standards Institute. Toledo, OH: The Laser Institute of America, 1992.
15. Adler R.Proc. IRE. 1946, 34:351.
16. Pantell R H. The laser oscillar with an external signal. Proc. IEEE. 1965, 53:474.
17. Tang C L and Statz H. Phase-Locking of Laser Oscillators by Injected Signal. Appl J. Phys. 1967, 38: 323.
18. Stover H L and Steier W H. Locking of laser oscillators by light injection. Appl.Phys.Lett. 1966, 8: 91.
19. Bruzek C J and Freiberg R J. Hybrid Injection Locking of Higher Power CO2 Lasers. IEEEQE-8, 1972:641.
20. Bjorkholm J E and Szabo A Frequency control of a pulsed optical parametric oscillator by radiation injection. Appl.Phys.Lett. 1969,15:171.
21. Erickson L E and Szabo A.Spectral narrowing of dye laser output by injection of monochromatic radiation into the laser cavity.Appl.Phys.Lett. 1971,18:433.
22. Vrehen Q H F and Breimer A J. Spectral properties of a pulsed dye laser with monochromatic injection.Opt.Comm. 1972, 4:416.
23. Moses E I, Turner J J and Tang C L. Mode locking of laser oscillators by injection locking. Appl.Phys.Lett. 1976, 28:258,
24. Blit S,Ganiel U and Treves D.Appl.Phys. 1977,12:69.
25. Rebhan U and Hildebrandt J.Opt.Comm. 1979, 31:69.
26. Okada T, Maeda Mand Miyazoe Y. Spectral Narrowing of a Flashlamp-Pumped High-Energy Dye Laser by Two-Stage Injection Locking.IEEEQE-15, 1979:616.
27. Brockman P, Bair C H, Barnes J C et al. Pulsed injection control of a titanium-doped sapphire laser Opt. Lett. 1986,11:712.
28. Raymond T D and Smith A V. Injection-seeded titanium-doped-sapphire laser.Opt.Lett. 1991,16:33.
29. Charles E. Hamilton. Single-frequency, injection-seeded Ti:sapphire ring laser with high temporal precision. Opt. Lett., 1992,Vol.17, No.10.
30. Jirong Yu,Upendra N. Singh and Norman P. Barnes,MulugetaPetros.125-mJ diode-pumped injection-seeded Ho:Tm:YLF laser. Opt.Lett. 1998, Vol.23, No.10.
31. U. N. Singh, J. Yu, M.Petros, N. P. Barnes, J. A. Williams-Byrd, G. E. Lockard And E. A. modlin. Injection-seeded, Room-temperature, Diode-pumped Ho, Tm:YLF Laser with Output Energy of 600mJ at 10Hz. OSA Trends in Optics And Photonics Series. 1998,19:194-196.
32. U. N. Singh. Development of High-pulse Energy Ho, Tm:YLF Coherent Transmitters. SPIE. 1998, 3380: 70-74.
33. J. A. Williams-Byrd, U. N. Singh, N. P. Barnes, G. E. Lockard, E. A. Modlin And J. Yu. Room-temperature, Diode-pumped Ho, Tm:YLF Laser Amplifiers Generating 700 mJ at 2μm. OSA Trends in Optics and Photonics Series. 1997, 10:199-201.
34. Hirotake Fukuoka, Minoru Kadoya, Kaoru Asaba, Kazuhiro Asai, Kouhei Mizutani and Toshikazu Itabe. Injection Seeded Tm, Ho:YLF Laser. SPIE. 2001, 4153: 455-462.
35. Allen K.Hankla and Timothy J.Carrig. Q-switch, injection-seeded, Single-frequency,Yb:YAG disk laser. OSA TOPS.2002,Vol.68.
36. Kohei Takeno, Takafumi Ozeki, Shigenori Moriwaki, and Norikatsu Mio. 100 W, single-frequency operation of aninjection-locked Nd:YAG laser. Opt. Lett. 2005, Vol 30, No.16.
37. Maik Frede, Ralf Wilhelm, Dietmar Kracht, Carsten Fallnich. Frank Seifert, Benno Willke. 195 W Injection-Locked Single-Frequency Laser System. OSA.CAM1.2005.
38.俞本立,钱景仁,罗家童.注入锁定光纤环形腔激光器实验研究.量子电子学报. 2001, Vol.18, No.6.
39.闫树斌,刘涛.声光偏频亚多普勒光谱无调制激光频率锁定.光学学报. 2004, Vol.24, No.10.
40.马杰,赵延霆,赵建明.利用偏振光谱对外腔式半导体激光器实现无调制锁频.中国激光. 2005, Vol.32, No.12.
41.杨海菁,王彦华,张天才,王军民.基于共焦法布里-珀罗腔的无调制激光频率锁定.中国激光. 2006, Vol.33, No.3.
42.赵卫,王涛,杨延龙,陈果夫,朱宝亮.用于种子注入的微型二极管泵浦激光器.光子学报. 2003, Vol.32.No.7.
43.郭少锋,林文雄,黎全.种子注入式单纵单横电光调Q激光器.中国激光. 2006, Vol.33.No.12.
44.蓝信炬.激光技术.科学出版社.北京.2002:164-165.
45. Ganiel U,Hardy A and Treves D.IEEEQE-12, 1976:704.
46. Barnes N P and Barnes J C.IEEEQE-29, 1993:2670.
47.石顺祥.物理光学与应用光学.西安电子科技大学出版社.西安.2000:90-91.
48. W.克西耐尔著.孙文译.固体激光工程.科学出版社.北京.2002:216-217.
49.季家镕,冯莹,肖贵遐.环形腔扫描干涉仪及其模式匹配研究.激光技术. 1997, 21(5):277-280.
50. H Kogelnik. Coupling and conversion coefficients for optical modes [A]. Symposium on Quasi-Optics [C].1964:333-345.
51.肖贵遐,丁金星.腔失调对模耦合的影响.激光杂志,1996 ,17 (3) :127-130.
52.王雨三,张中华,林殿阳.光电子学原理与应用.哈尔滨工业大学出版社. 2002:105-107.
53.万钧力.用环形腔扫描干涉仪测量激光模间隔的研究.三峡大学学报(自然科学版).2003, Vol.25(1).
2. Park Y K, Giuliani G, Byer R L. Stable single-axial-mode operation of an unstable-resonator Nd:YAG oscillator by injection locking[J].Optics Letters.1980,5(3):96 -98.
3. Alcock A J, Corkum P B, James D J, et al. Selection of single, mode locked CO2 laser pulses by semiconductor reflection switching[J].Optics Comm.1976, 18:543-545.
4. Bigio I J, Slatkine M. Injection2locking unstable resonator excimer lasers[J] .IEEE Journal of Quantum Elect ronics.1983,19 (9):426-1436.
5. Zayhowski J J, Mooradian A Frequency-modulated Nd:YAG microchip lasers[J]. Optics Letters.1989:14(12) 618-620.
6.张国威.可调谐激光技术.国防工业大学出版社.北京. 2002:248-249.
7. G. J. Koch, John,P. Deyst, Mark. E. Storm. Single-frequency Lasing of Monolithic Ho, Tm: YLF. Opt. Lett. 1993, 18, (15): 1235-1237.
8. G. J. Koch, R.E.Davis, A.N.Dharamsi, M.Petros and J.C. Mc Carthy. Differential Absorption Measurements of Atmospheric Water Vapor with A Coherent Lidar at 2050.532nm.Proceedings of Tenth Biennial Coherent Laser Radar Technology and Applications Conference.1999:69-71.
9. G. J. Koch, A. N. Dharamsi, C. M. Fitzgerald and J. C. Mc Carthy. Frequency Stabilization of A Ho, Tm:YLF Laser to Absorption Lines Of Carbon Dioxide. Appl Opt. 2000, 39(21):3664-3669.
10. G..J.Koch,B.W.Barnes,M.Petros,J.Y.Beyon,F.AmzajerdianJ.Yu,R.E.Davis,S.Cohe-rent Differential Absorption LIDAR Measurements of CO2.Appl.Opt. 2004, 43(26): 5092-5099.
11. G..J.Koch, M.Petros, J.Yu, and U.N.Singh. Precise Wavelength Control of a Single-frequency Pulsed Ho:Tm:YLF Laser. App.Opt.2002, 41(9):1718-1721.
12. U. N. Singh, J. Yu, M.Petros, N. P. Barnes, J. A. Williams-Byrd, G. E. Lockard, And E. A.modlin. Injection-seeded, Room-temperature, Diode-pumped Ho, Tm:YLF Laser with Output Energy of 600mJ at 10Hz. OSATrends in Optics And Photonics Series. 1998,19:194-196.
13. G. J. Koch, R. E. Davis, A. N. Dharamsi, M. Petros and J. C. Mc Carthy. Differential Absorption Measurements of Atmospheric Water Vapor with A Coherent LIDAR at 2050.532nm. Proceedings of Tenth Biennial Coherent Laser Radar Technology and Applications Conference. 1999:69-71.
14. American National Standard for the Safe Use of Lasers Z136.1-1992. American National Standards Institute. Toledo, OH: The Laser Institute of America, 1992.
15. Adler R.Proc. IRE. 1946, 34:351.
16. Pantell R H. The laser oscillar with an external signal. Proc. IEEE. 1965, 53:474.
17. Tang C L and Statz H. Phase-Locking of Laser Oscillators by Injected Signal. Appl J. Phys. 1967, 38: 323.
18. Stover H L and Steier W H. Locking of laser oscillators by light injection. Appl.Phys.Lett. 1966, 8: 91.
19. Bruzek C J and Freiberg R J. Hybrid Injection Locking of Higher Power CO2 Lasers. IEEEQE-8, 1972:641.
20. Bjorkholm J E and Szabo A Frequency control of a pulsed optical parametric oscillator by radiation injection. Appl.Phys.Lett. 1969,15:171.
21. Erickson L E and Szabo A.Spectral narrowing of dye laser output by injection of monochromatic radiation into the laser cavity.Appl.Phys.Lett. 1971,18:433.
22. Vrehen Q H F and Breimer A J. Spectral properties of a pulsed dye laser with monochromatic injection.Opt.Comm. 1972, 4:416.
23. Moses E I, Turner J J and Tang C L. Mode locking of laser oscillators by injection locking. Appl.Phys.Lett. 1976, 28:258,
24. Blit S,Ganiel U and Treves D.Appl.Phys. 1977,12:69.
25. Rebhan U and Hildebrandt J.Opt.Comm. 1979, 31:69.
26. Okada T, Maeda Mand Miyazoe Y. Spectral Narrowing of a Flashlamp-Pumped High-Energy Dye Laser by Two-Stage Injection Locking.IEEEQE-15, 1979:616.
27. Brockman P, Bair C H, Barnes J C et al. Pulsed injection control of a titanium-doped sapphire laser Opt. Lett. 1986,11:712.
28. Raymond T D and Smith A V. Injection-seeded titanium-doped-sapphire laser.Opt.Lett. 1991,16:33.
29. Charles E. Hamilton. Single-frequency, injection-seeded Ti:sapphire ring laser with high temporal precision. Opt. Lett., 1992,Vol.17, No.10.
30. Jirong Yu,Upendra N. Singh and Norman P. Barnes,MulugetaPetros.125-mJ diode-pumped injection-seeded Ho:Tm:YLF laser. Opt.Lett. 1998, Vol.23, No.10.
31. U. N. Singh, J. Yu, M.Petros, N. P. Barnes, J. A. Williams-Byrd, G. E. Lockard And E. A. modlin. Injection-seeded, Room-temperature, Diode-pumped Ho, Tm:YLF Laser with Output Energy of 600mJ at 10Hz. OSA Trends in Optics And Photonics Series. 1998,19:194-196.
32. U. N. Singh. Development of High-pulse Energy Ho, Tm:YLF Coherent Transmitters. SPIE. 1998, 3380: 70-74.
33. J. A. Williams-Byrd, U. N. Singh, N. P. Barnes, G. E. Lockard, E. A. Modlin And J. Yu. Room-temperature, Diode-pumped Ho, Tm:YLF Laser Amplifiers Generating 700 mJ at 2μm. OSA Trends in Optics and Photonics Series. 1997, 10:199-201.
34. Hirotake Fukuoka, Minoru Kadoya, Kaoru Asaba, Kazuhiro Asai, Kouhei Mizutani and Toshikazu Itabe. Injection Seeded Tm, Ho:YLF Laser. SPIE. 2001, 4153: 455-462.
35. Allen K.Hankla and Timothy J.Carrig. Q-switch, injection-seeded, Single-frequency,Yb:YAG disk laser. OSA TOPS.2002,Vol.68.
36. Kohei Takeno, Takafumi Ozeki, Shigenori Moriwaki, and Norikatsu Mio. 100 W, single-frequency operation of aninjection-locked Nd:YAG laser. Opt. Lett. 2005, Vol 30, No.16.
37. Maik Frede, Ralf Wilhelm, Dietmar Kracht, Carsten Fallnich. Frank Seifert, Benno Willke. 195 W Injection-Locked Single-Frequency Laser System. OSA.CAM1.2005.
38.俞本立,钱景仁,罗家童.注入锁定光纤环形腔激光器实验研究.量子电子学报. 2001, Vol.18, No.6.
39.闫树斌,刘涛.声光偏频亚多普勒光谱无调制激光频率锁定.光学学报. 2004, Vol.24, No.10.
40.马杰,赵延霆,赵建明.利用偏振光谱对外腔式半导体激光器实现无调制锁频.中国激光. 2005, Vol.32, No.12.
41.杨海菁,王彦华,张天才,王军民.基于共焦法布里-珀罗腔的无调制激光频率锁定.中国激光. 2006, Vol.33, No.3.
42.赵卫,王涛,杨延龙,陈果夫,朱宝亮.用于种子注入的微型二极管泵浦激光器.光子学报. 2003, Vol.32.No.7.
43.郭少锋,林文雄,黎全.种子注入式单纵单横电光调Q激光器.中国激光. 2006, Vol.33.No.12.
44.蓝信炬.激光技术.科学出版社.北京.2002:164-165.
45. Ganiel U,Hardy A and Treves D.IEEEQE-12, 1976:704.
46. Barnes N P and Barnes J C.IEEEQE-29, 1993:2670.
47.石顺祥.物理光学与应用光学.西安电子科技大学出版社.西安.2000:90-91.
48. W.克西耐尔著.孙文译.固体激光工程.科学出版社.北京.2002:216-217.
49.季家镕,冯莹,肖贵遐.环形腔扫描干涉仪及其模式匹配研究.激光技术. 1997, 21(5):277-280.
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