掺Cr~(4+)：YAG晶体被动调Q激光器的研究
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摘要
使用激光二极管(LD)泵浦的固体激光器,与传统的激光器相比可以实现高输出功率、高重复频率,窄脉宽的激光输出。这种激光器的优点是体积小、效率高、结构简单、价格低廉等,因此在工业、科研、军事、医学、等领域中有着广泛的应用前景。成为海内外学者研究的热点。
本论文采用光纤耦合的LD作为泵浦源,Nd3+:YAG晶体作为激光器的工作物质,可饱和吸收体Cr4+:YAG作为被动Q开关,并对4d3+:YAG晶体进行端面泵浦,分析研究了被动调Q激光器的脉冲输出特性。主要做了以下几个方面的工作：
1)回顾了LD泵浦的固体激光器发展历程,讨论了典型被动Q开关材料Cr4+:YAG晶体的特性以及调Q激光器的工作原理。
2)运用高斯分布近似下的速率方程,对调Q激光器进行了理论分析。
3)实现了LD泵浦Nd3+:YAG晶体被动调Q1064nm激光器的运转,测量了不同泵浦功率、输出镜透过率和腔长下的输出功率、重复率、脉冲宽度；同时对实验结果进行了理论分析,得到了一致的结果。
4)考虑到热效应的影响,对Q开关晶体的位置进行了研究,得出了Q开关晶体在谐振腔内的最佳位置,在此基础下,也确定了泵浦源的最佳位置。
Compared with other lasers, the output of the laser-diode (LD) pumped solid-state laser is special in the high peak power, the high pulse repetition rate and the narrow pulse width. This kind of laser has been widely applied in the fields such as industrial, scientific research, military and medical, due to its advantages such as compact size, high efficient, simplicity and inexpensive. It has become the research focus of scholars from home and abroad.
In this dissertation, by taking the fiber-coupled laser-diode as the pump source, Nd3+:YAG crystal as the gain medium, and the Cr4+:YAG storable absorber as the passive Q-switch, as well as by using the end-pumped to Nd3+:YAG crystal, we have studied the performance of the output pulse in the passively Q-switched laser. The main points of this paper can be summarized as follows:
1) The development process of the LD pumped solid-state laser are reviewed. The characteristics of Cr4+:YAG crystal and theoretical foundation of Q-switch are analysed.
2) The properties of the Q-switched laser have been theoretically analyzed by using of the Coupling rate equations under Gaussian distribution approximation
3) The LD-pumped passively Q-switched Nd3+:YAG 1064nm laser has been realized; the output power, pulse repetition rate and pulse width have been worked out, when they at different pumped powers, transmittances of output mirror and cavity lengths; and the experimental results have been theoretically analyzed to a consistent conclusion.
4) By considering the thermal effect of the medium, the optimal position of the Cr4+:YAG crystal in the laser cavity have been obtained from the study, and on the basis of this conclusion, the optimal position of the pump source have been found.
本论文采用光纤耦合的LD作为泵浦源,Nd3+:YAG晶体作为激光器的工作物质,可饱和吸收体Cr4+:YAG作为被动Q开关,并对4d3+:YAG晶体进行端面泵浦,分析研究了被动调Q激光器的脉冲输出特性。主要做了以下几个方面的工作：
1)回顾了LD泵浦的固体激光器发展历程,讨论了典型被动Q开关材料Cr4+:YAG晶体的特性以及调Q激光器的工作原理。
2)运用高斯分布近似下的速率方程,对调Q激光器进行了理论分析。
3)实现了LD泵浦Nd3+:YAG晶体被动调Q1064nm激光器的运转,测量了不同泵浦功率、输出镜透过率和腔长下的输出功率、重复率、脉冲宽度；同时对实验结果进行了理论分析,得到了一致的结果。
4)考虑到热效应的影响,对Q开关晶体的位置进行了研究,得出了Q开关晶体在谐振腔内的最佳位置,在此基础下,也确定了泵浦源的最佳位置。
Compared with other lasers, the output of the laser-diode (LD) pumped solid-state laser is special in the high peak power, the high pulse repetition rate and the narrow pulse width. This kind of laser has been widely applied in the fields such as industrial, scientific research, military and medical, due to its advantages such as compact size, high efficient, simplicity and inexpensive. It has become the research focus of scholars from home and abroad.
In this dissertation, by taking the fiber-coupled laser-diode as the pump source, Nd3+:YAG crystal as the gain medium, and the Cr4+:YAG storable absorber as the passive Q-switch, as well as by using the end-pumped to Nd3+:YAG crystal, we have studied the performance of the output pulse in the passively Q-switched laser. The main points of this paper can be summarized as follows:
1) The development process of the LD pumped solid-state laser are reviewed. The characteristics of Cr4+:YAG crystal and theoretical foundation of Q-switch are analysed.
2) The properties of the Q-switched laser have been theoretically analyzed by using of the Coupling rate equations under Gaussian distribution approximation
3) The LD-pumped passively Q-switched Nd3+:YAG 1064nm laser has been realized; the output power, pulse repetition rate and pulse width have been worked out, when they at different pumped powers, transmittances of output mirror and cavity lengths; and the experimental results have been theoretically analyzed to a consistent conclusion.
4) By considering the thermal effect of the medium, the optimal position of the Cr4+:YAG crystal in the laser cavity have been obtained from the study, and on the basis of this conclusion, the optimal position of the pump source have been found.
引文
[1]周炳琨,高以智,陈倜嵘等.激光源里[M].6版.北京：国防工业出版社,2009：144-166.
[2]蓝信钜.激光技术[M].3版.北京：科学出版社,2009：75-77.
[3]杨永明,过振,王石语等.端面形变对泵浦DPL参数的影响[J].红外与激光工程,2006,35(2)：148-152.
[4]将新颖,郑建刚,段文涛等Cr4+:YAG被动调Q激光器输出特性[J].强激光与粒子束,2011,23(3)：586-588.
[5]张中士.LD泵浦Nd:Y(Gd)VO4晶体Cr4+:YAG被动调Q激光特性研究[D].济南：山东大学,2007.
[6]杨林,黄维玲,丘军林等Cr4+:YAG被动调Q激光器中受激粒子上转换效应对脉冲的影响研究[J].物理学报,2003,52(10)：2471-2475.
[7]毕拉力·木呼提江,阿力甫·扎依提,帕力哈提·米吉提Cr4+:YAG被动调Q与被动锁模的研究[J].新疆师范大学学报,2009,28(1)：59-62.
[8]LIU Ying, LIU Cheng-cheng, NIU Rong-lian, et al. Diode-pumped Doubly Q-switched Nd:YAG Laser with Acoustic-optical Modulator and Cr4+:YAG Saturable Absorber[J]. Semiconductor Photonics and Technology,2010,16:98-102.
[9]欧阳斌,丁彦华,万小珂等Cr4+:YAG的可饱和吸收特性与被动Q开关性能研究[J].光学学报,1996,16(12)：1666-1670.
[10]臧竞存,隋宁菠,邹玉林等Cr4+:YAG晶体调Q激光器研究进展[J].激光杂志2005,26(6)：4-6.
[11]端面抽运Tm,Ho:YLF激光器热转换系数及热透镜效应的研究[J].物理学报,2007,56(4)：2196-2201.
[12]陈昭炫,蔡志平,黄朝红等.LD端面泵浦固体激光器谐振腔的研究[J].厦门大学学报,2005,44：343-346.
[13]周城,张仲,赵朋等.LD泵浦Nd3+:GdVO4/Cr4+:YAG固体激光器[J].光子学报,2006,35(6)：801-803.
[14]李武军,吴昊,于金涛.LD泵浦Nd3+:YAG晶体被动调Q激光器的实验研究[J].西安工业大学学报,2010,30(3)：215-218.
[15]黄朝红,肖敬忠,张庆礼等.新型Q开关晶体Cr4+:YAG的生长和被动调Q研究[J].量子电子学报,2003,20(1)：26-29.
[16]吴锋,李宇飞,孙渝明等.LD泵浦的声光调Q1.34umNd:GdVO4激光器[J].红外与激光工程,2007,36(2)：179-185.
[17]WU Wei, LI Gui-qiu, ZHAO Sheng-zhi, et al. Pulse width reduction indiode pumped doubly Q-switchedNd:GdVO4/KTP green laser[J]. Chinese Optics Letters,2005, 3(7):402-404.
[18]KUCK S, PETERMANN K. POHLMANN U, et al. Near-infrared emission of Cr4+-doped gamets:lifetimes, quantum efficiencies, and emission cross section[J]. Phy. Rev. B,1995,51:17323-17331..
[19]COMASKEY B J. High average power diode pumped slab laser[J]. IEEE J Quant Elect.1992.28(4):992-996.
[20]WANG Hai-lin, HUANG Wei-ling, ZHOU Zhuo-you, et al. High power CW diode-side-pumped Nd:YAG rod laser[J]. Chinese Opt. Lett.,2003,1(9):541-543.
[21]ZHENG Jia-an, ZHAO Sheng-zhi, CHEN Lei. Laser-diode end-pumped passively Q-switched intracavity doubling Nd:YVO4/KTP laser with Cr4+:YAG saturable absorber[J]. Opt. Eng.,2002,41:1970-1973.
[22]蔡军,张晓娟,徐涛.热透镜效应对固体激光器输出影响研究[J].光电技术应用,2011,,26(1)：15-17.
[23]王为宇,巩马理,刘占兴等.被动调Q固体激光器的稳定性及增益预泵浦技术[J].激光与红外,2000,30(2)：74-77.
[24]应建新,张彬,廖皓杰等Cr4+:YAG被动调QNd:YAG陶瓷激光器输出特性研究[J].光电工程,2010,37：56-60.
[25]王淑香,陈云琳,颜彩繁等.微片激光器的最新研究进展[J].量子电子学报,,2007,,24(4)：401-406.
[26]张秋琳,苏红新,孙江等.LD抽运被动调Q固体激光器的脉冲稳定性[J].物理学报,2007,56(10)：5818-5820.
[27]余本海,倪永军,娄国营Nd:YAG激光器的热透镜效应及其对激光器输出的影响[J].信阳师范学院学报,2004,17(2)：166-169.
[28]李荣,伊厚会Nd:YAG被动调Q激光增的研究及其设计[J].河北师范大学学报,,2011,35(6)：589-593.
[29]高涛.激光二极管泵浦Cr4+:YAG被动调Q的Nd3+:YAG微片式激光器[D].成都：电子科技大学,2001.
[30]聂劲松.热透镜效应对谐振腔稳定行影响研究[J].激光杂志,2011,32(1)：4-5.
[31]董俊,马剑.被动调Q掺Yb3+激光材料固体微片激光器的研究进展[J].中国激光,,2010,37(9)：2278-2288.
[32]LIU Hui-lan. Study of Passive Q-switch Mode-locked Characteristic of Pulse LD Pump Nd:YVO4/Cr4+:YAG[R]. Dezhou:Department of Physics Dezhou University,2009.
[33]ZHENG Jia-an, ZHAO Sheng-zhi, WANG Qing-pu, et al. Laser-diode end-pumped passively Q-switched Nd:YVO4 laser with Cr4+:YAG saturable absorber[J]. Opt. Eng., 2002,41:2271-2275.
[34]DEGNAN J J. Theory of the Optimally Coupled Q-Switched Laser[J].IEEE, QE, 1989,25(2):214-220.
[35]DU Ke-ming, ZHANG Heng-li, LI Dai-jun, et al. Electro-optically Q-switched Nd:YVO4 slab laser with a high repetition rate a short pulse width[J]. Opt. Lett.,2003.28(2): 87-89.
[36]SONG Bao-an ZHAO Wei-jiang, REN De-ming, et al. Passively Q-switched laser with single longitudinal mode based on the frequency selection of grating and F-P etalon in twisted-mode folded cavity [J]. Chinese Optics Letters,2009,7:805-808.
[37]TIAN Wen-miao, YANG Feng, GAO Li-yan, et al. Q-switched and Mode-Locker Characteristics of Cr4+:YAG Crystal[J].2006,12:145-149.
[38]吴昊.被动调Q激光器输出特性的控制技术研究[D].西安：西安工业大学,2010.
[39]曾钦勇,万勇,朱大勇等.半导体泵浦被动调Q高重频Nd:YAG激光器[J].红外与激光工程,2006,35：177-182.
[40]王薇,朱长虹,李正佳.钕激光器被动调Q技术的发展[J].光电子技术与信息,2003,16(4)：8-12.
[41]牛荣莲,刘成成,刘莹等.基于侧面热对流的LD泵浦Yb:KGd(WO4)2热透镜效应研究[J].光子学报,2011,40(1)：79-82.
[2]蓝信钜.激光技术[M].3版.北京：科学出版社,2009：75-77.
[3]杨永明,过振,王石语等.端面形变对泵浦DPL参数的影响[J].红外与激光工程,2006,35(2)：148-152.
[4]将新颖,郑建刚,段文涛等Cr4+:YAG被动调Q激光器输出特性[J].强激光与粒子束,2011,23(3)：586-588.
[5]张中士.LD泵浦Nd:Y(Gd)VO4晶体Cr4+:YAG被动调Q激光特性研究[D].济南：山东大学,2007.
[6]杨林,黄维玲,丘军林等Cr4+:YAG被动调Q激光器中受激粒子上转换效应对脉冲的影响研究[J].物理学报,2003,52(10)：2471-2475.
[7]毕拉力·木呼提江,阿力甫·扎依提,帕力哈提·米吉提Cr4+:YAG被动调Q与被动锁模的研究[J].新疆师范大学学报,2009,28(1)：59-62.
[8]LIU Ying, LIU Cheng-cheng, NIU Rong-lian, et al. Diode-pumped Doubly Q-switched Nd:YAG Laser with Acoustic-optical Modulator and Cr4+:YAG Saturable Absorber[J]. Semiconductor Photonics and Technology,2010,16:98-102.
[9]欧阳斌,丁彦华,万小珂等Cr4+:YAG的可饱和吸收特性与被动Q开关性能研究[J].光学学报,1996,16(12)：1666-1670.
[10]臧竞存,隋宁菠,邹玉林等Cr4+:YAG晶体调Q激光器研究进展[J].激光杂志2005,26(6)：4-6.
[11]端面抽运Tm,Ho:YLF激光器热转换系数及热透镜效应的研究[J].物理学报,2007,56(4)：2196-2201.
[12]陈昭炫,蔡志平,黄朝红等.LD端面泵浦固体激光器谐振腔的研究[J].厦门大学学报,2005,44：343-346.
[13]周城,张仲,赵朋等.LD泵浦Nd3+:GdVO4/Cr4+:YAG固体激光器[J].光子学报,2006,35(6)：801-803.
[14]李武军,吴昊,于金涛.LD泵浦Nd3+:YAG晶体被动调Q激光器的实验研究[J].西安工业大学学报,2010,30(3)：215-218.
[15]黄朝红,肖敬忠,张庆礼等.新型Q开关晶体Cr4+:YAG的生长和被动调Q研究[J].量子电子学报,2003,20(1)：26-29.
[16]吴锋,李宇飞,孙渝明等.LD泵浦的声光调Q1.34umNd:GdVO4激光器[J].红外与激光工程,2007,36(2)：179-185.
[17]WU Wei, LI Gui-qiu, ZHAO Sheng-zhi, et al. Pulse width reduction indiode pumped doubly Q-switchedNd:GdVO4/KTP green laser[J]. Chinese Optics Letters,2005, 3(7):402-404.
[18]KUCK S, PETERMANN K. POHLMANN U, et al. Near-infrared emission of Cr4+-doped gamets:lifetimes, quantum efficiencies, and emission cross section[J]. Phy. Rev. B,1995,51:17323-17331..
[19]COMASKEY B J. High average power diode pumped slab laser[J]. IEEE J Quant Elect.1992.28(4):992-996.
[20]WANG Hai-lin, HUANG Wei-ling, ZHOU Zhuo-you, et al. High power CW diode-side-pumped Nd:YAG rod laser[J]. Chinese Opt. Lett.,2003,1(9):541-543.
[21]ZHENG Jia-an, ZHAO Sheng-zhi, CHEN Lei. Laser-diode end-pumped passively Q-switched intracavity doubling Nd:YVO4/KTP laser with Cr4+:YAG saturable absorber[J]. Opt. Eng.,2002,41:1970-1973.
[22]蔡军,张晓娟,徐涛.热透镜效应对固体激光器输出影响研究[J].光电技术应用,2011,,26(1)：15-17.
[23]王为宇,巩马理,刘占兴等.被动调Q固体激光器的稳定性及增益预泵浦技术[J].激光与红外,2000,30(2)：74-77.
[24]应建新,张彬,廖皓杰等Cr4+:YAG被动调QNd:YAG陶瓷激光器输出特性研究[J].光电工程,2010,37：56-60.
[25]王淑香,陈云琳,颜彩繁等.微片激光器的最新研究进展[J].量子电子学报,,2007,,24(4)：401-406.
[26]张秋琳,苏红新,孙江等.LD抽运被动调Q固体激光器的脉冲稳定性[J].物理学报,2007,56(10)：5818-5820.
[27]余本海,倪永军,娄国营Nd:YAG激光器的热透镜效应及其对激光器输出的影响[J].信阳师范学院学报,2004,17(2)：166-169.
[28]李荣,伊厚会Nd:YAG被动调Q激光增的研究及其设计[J].河北师范大学学报,,2011,35(6)：589-593.
[29]高涛.激光二极管泵浦Cr4+:YAG被动调Q的Nd3+:YAG微片式激光器[D].成都：电子科技大学,2001.
[30]聂劲松.热透镜效应对谐振腔稳定行影响研究[J].激光杂志,2011,32(1)：4-5.
[31]董俊,马剑.被动调Q掺Yb3+激光材料固体微片激光器的研究进展[J].中国激光,,2010,37(9)：2278-2288.
[32]LIU Hui-lan. Study of Passive Q-switch Mode-locked Characteristic of Pulse LD Pump Nd:YVO4/Cr4+:YAG[R]. Dezhou:Department of Physics Dezhou University,2009.
[33]ZHENG Jia-an, ZHAO Sheng-zhi, WANG Qing-pu, et al. Laser-diode end-pumped passively Q-switched Nd:YVO4 laser with Cr4+:YAG saturable absorber[J]. Opt. Eng., 2002,41:2271-2275.
[34]DEGNAN J J. Theory of the Optimally Coupled Q-Switched Laser[J].IEEE, QE, 1989,25(2):214-220.
[35]DU Ke-ming, ZHANG Heng-li, LI Dai-jun, et al. Electro-optically Q-switched Nd:YVO4 slab laser with a high repetition rate a short pulse width[J]. Opt. Lett.,2003.28(2): 87-89.
[36]SONG Bao-an ZHAO Wei-jiang, REN De-ming, et al. Passively Q-switched laser with single longitudinal mode based on the frequency selection of grating and F-P etalon in twisted-mode folded cavity [J]. Chinese Optics Letters,2009,7:805-808.
[37]TIAN Wen-miao, YANG Feng, GAO Li-yan, et al. Q-switched and Mode-Locker Characteristics of Cr4+:YAG Crystal[J].2006,12:145-149.
[38]吴昊.被动调Q激光器输出特性的控制技术研究[D].西安：西安工业大学,2010.
[39]曾钦勇,万勇,朱大勇等.半导体泵浦被动调Q高重频Nd:YAG激光器[J].红外与激光工程,2006,35：177-182.
[40]王薇,朱长虹,李正佳.钕激光器被动调Q技术的发展[J].光电子技术与信息,2003,16(4)：8-12.
[41]牛荣莲,刘成成,刘莹等.基于侧面热对流的LD泵浦Yb:KGd(WO4)2热透镜效应研究[J].光子学报,2011,40(1)：79-82.