全固态调Q、调Q锁模激光泵浦的光参量振荡及拉曼散射特性研究

发布时间：2018-02-20 21:27

  本文关键词： 光参量振荡 受激拉曼散射 亚纳秒 双损耗调制 调Q 调Q锁模 Nd MgO:LiTaO_3晶体 Nd MgO:LiNbO_3晶体 单层石墨烯 KTP　出处：《山东大学》2016年博士论文　论文类型：学位论文

【摘要】：自从1961年Franken等人利用石英晶体(Si02)实现倍频,成功将红宝石激光扩展到紫外波段,第一次实现了真正意义的频率变换以来,非线性频率变换就是激光科学范围内最吸引人的课题之一。目前,使用非线性光学晶体来实现频率变换的技术是获得新的相干光源最有效、最可靠也是最普遍的方法。非线性晶体的二阶非线性效应(即三波相互作用过程)和三阶非线性效应(即四波相互作用过程)都得到了深入而又广泛的研究。在上述频率变换技术中,频率下转换技术,如差频、光参量过程和受激拉曼散射,是最有潜力获取中红外相干光源的手段。本论文基于单块KTP晶体分别使用调Q、双调Q和调Q双波长激光器作为泵浦源实现了光参量振荡和受激拉曼散射两个过程,并建立一套耦合速率方程,对实验结果进行了理论模拟和分析,结果表明两者吻合得很好；使用克尔透镜锁模和双损耗调制调Q锁模激光器作为泵浦,首次实现了内腔式锁模激光泵浦的光参量振荡器,输出的脉宽在次纳秒(Sub-nanosecond)量级,并结合速率方程理论,建立理论模型,数值模拟和实验结果基本吻合；首次使用KTP作为拉曼增益介质,使用1050 nm Yb:YAG激光作为泵浦,成功获得了高阶Stokes光输出,脉冲宽度约为764 ps,估算了KTP的有效增益系数；首次实现了W级σ偏振Nd,MgO:LiNbO3 1094 nm激光输出,同时作为泵浦源,获得了KTP OPO 1630 nm信号光。本论文的主要研究内容总结如下：(1)首次实现了单层石墨烯调Q Nd,MgO:LiTaO31082 nm和1092 nm双波长激光运转,获得了176 ns的最小脉宽和2.75μJ的最大单脉冲能量。(第二章第一节)(2)首次实现了双波长调Q锁模Nd:GGG激光输出,调制深度近乎100%,脉宽估计为908 ps。(第二章第二节)(3)以KTP晶体作为多功能非线性晶体,同时实现了高阶Stokes和OPO信号光的振荡输出。在LD泵浦达到10.5 W时,信号波的最大输出功率高达302mW,最小脉宽仅1.61 ns,同时二阶和三阶Stokes光的最大功率为11 5 mW,最小脉宽为2.88 ns,波长分别为1124.9和1160.7 nm。相应的光光转化效率为2.88%和1.1%。光束质量因子M2在1.2左右。(第三章第一节)(4)为进一步压缩信号光脉宽,采用双损耗技术,即同时使用两种饱和吸收体,同时获得了OPO和SRS过程,而且信号波输出的最高功率为208 mW,脉冲宽度被压缩到了580 ps,峰值功率提高到43.7 kW。当调整KTP倾斜角度时,首次观察到波数为154 cm-1的频移。(第三章第一节)(5)、用Cr4+:YAG调Q的Nd:LGGG激光作为泵浦源,实现了双波长泵浦的多种非线性效应,即同时存在的SRS和OPO过程,信号光最大功率为448 mW,脉冲宽度为850 ps,信号光的峰值功率高达30.6 kW,单脉冲能量为26μJ,并从双波长速率方程出发对此过程进行了理论研究。(第三章第二节)(6)、首次用LD泵浦c切Nd,MgO:LiNbO3晶体,获得了1.47 W的连续激光输出,这是首次突破W级输出,较之前的报道至少提高了20倍。用KTP晶体实现了OPO 1.63 μm信号光运转,其脉冲宽度为1.69 ns,峰值功率为11.4 kW,较以前的报道提高了3倍。(第三章第三节)(7)、首次实现了Yb:YAG 1050 nm激光泵浦KTP实现高阶拉曼光输出,三阶Stokes光的脉宽约为764 ps。反Stokes光的脉宽为1.54 ns,峰值功率为3.5kW。光束质量在两个方向上分别为1.64和1.48,表明Stokes、基频光和反Stokes光有很好的共线。KTP有效拉曼增益系数估计为2.1 cm/GW。(第三章第四节)(8)、首次研究了KLM激光泵浦的内腔OPO,用AOM选取锁模脉冲提高峰值功率,分别用Nd:GGG和键合Nd:YVO4激光泵浦KTP,成功完成了高峰值功率、高能量的亚纳秒1.57μm信号波输出：其中KLM Nd:GGG/KTP OPO信号光的最高峰值功率为102 kW, KLM Nd:YVO4/KTP OPO信号波的最小脉宽约为120 ps,同时结合速率方程模拟了实验结果。(第四章第一、二节)(9)、采用AO和Cr4+:YAG主被动双损耗QML激光作为腔内OPO的泵浦光,并采用V型腔结构,在8.25 w的二极管泵浦情况下,AO的调制周期固定为1 ms(即重复率为1 kHz)时得到了信号光最高输出能量为96μJ、包络宽度为2.5 ns。当声光开关频率在5 kHz时信号波输出的功率达到最大,高达156 mW,也是目前QML激光泵浦内腔式OPO信号光的最高输出功率。同时,信号光的光束质量因子M2经测小于1.5。(第五章第一节)(10)、采用AO和Cr4+:YAG主被动双损耗技术,首次获得了单锁模脉冲KTP OPO,当二极管泵浦为10.5 W、声光开关频率为2 kHz时,信号波的最小脉宽为450 ps,峰值功率高达35.5 kW,并研究了信号光输出波长与温度之间的关系,发现其信号光波长随温度的升高有0.027 nm/℃的蓝移率。同时建立一套基于QML锁模泵浦IOPO的速率方程,通过数值模拟发现,脉冲波形和输出能量基本和实验值一致。(第五章第二节)本论文的主要创新点如下：(1)、首次利用单块KTP晶体实现了高阶Stokes光和光参量振荡两种非线性过程,光束质量因子M2在1.2左右。(2)、首次实现了双调Q激光器泵浦的受激拉曼散射和光参量振荡过程,其中,信号光输出脉冲宽度首次压缩为580 ps。(3)、第一次实现了双波长激光器泵浦的多种非线性频率下转换过程,并建立了一套耦合速率方程,理论结果和实验结果基本吻合。(4)、首次实现了KLM激光器泵浦的内腔式OPO运转,实现了高峰值功率信号光输出。(5)、第一次实现了主被动双损耗调制QML激光泵浦的内腔式OPO,获得了亚纳秒信号光的稳定输出。(6)、首次成功获得了单锁模脉冲激光泵浦OPO,信号光脉宽约为450 ps,结合调Q锁模激光的波动机制,建立相应的模型。(7)、实现了1150 nm Yb:YAG/KTP三阶Stokes光输出,脉宽约为764 ps,经估算,KTP的有效拉曼增益系数为2.1 cm/GW。(8)、首次实现了W级Nd,MgO:LiNbO3晶体激光,并用获得了1630 nm信号光。
[Abstract]:Since 1961, Franken et al use quartz crystal (Si02) to achieve frequency, success will be extended to the ruby laser ultraviolet band, the first time since the implementation of the frequency conversion of the true meaning of the subject, one of the nonlinear frequency conversion of laser science is within the scope of the most attractive. At present, the use of nonlinear optical crystal to realize frequency conversion technology is new the coherent light source is the most effective, most reliable and most common method. Two order nonlinear effect of nonlinear crystal (three wave interaction) and three order nonlinear effect (i.e. four wave interaction) have been widely studied. The depth and frequency conversion technology, frequency conversion technology, such as difference frequency, optical parametric process and stimulated Raman scattering, is the most potential gain in the infrared coherent light source. The single KTP crystal were used based on Q, Q and Q double double Wavelength laser as the pump source to achieve optical parametric oscillation and stimulated Raman scattering of two processes, and to establish a set of coupled rate equations, the experimental results are the theoretical simulation and analysis, the results showed that both are in good agreement; the use of a Kerr lens mode-locked and double loss modulation Q mode-locked laser as the pump for the first time. The optical parametric oscillator intracavity pumped mode-locked laser, the output pulse width in the sub nanosecond magnitude (Sub-nanosecond), and combined with the rate equation theory, establishes the theoretical model, numerical simulation and experimental results are basically identical; KTP is used for the first time as the Raman gain medium, using 1050 nm Yb:YAG laser as the pump, successfully obtained high order Stokes light output, pulse width is about 764 PS, estimated the effective gain coefficient of KTP; for the first time to achieve the level of W Nd MgO:LiNbO3 1094 sigma polarization, nm laser output, at the same time as the pump source, get KTP OPO 1630 nm signal light. The main research contents of this thesis are summarized as follows: (1) for the first time the graphene Q Nd, MgO:LiTaO31082 nm and 1092 nm dual wavelength laser operation, to obtain the maximum and minimum pulse width of 176 ns and 2.75 J pulse energy. (the first section of the second chapter () 2) for the first time to achieve a dual wavelength tunable Q mode-locked Nd:GGG laser, pulse width modulation depth of nearly 100%, is estimated to be 908 PS. (second: Second) (3) by using KTP crystal as multifunctional nonlinear crystal, while achieving the oscillation output of high order Stokes and OPO signal light. Up to 10.5 W when pumped at LD the maximum output power, signal waves up to 302mW, the minimum pulse width is only 1.61 ns, and the maximum power of two order and three order Stokes light is 115 mW, the minimum pulse width of 2.88 ns wavelength, respectively 1124.9 and 1160.7 nm. corresponding to the optical conversion efficiency is 2.88% 1.1%. and beam quality factor M2 in 1.2 . (third chapter) (4) for further compression of signal pulse width, double loss technology, which also use two kinds of saturated absorber, also won the OPO and SRS process, and the maximum power output signal wave is 208 mW, the pulse width is compressed to 580 PS, the peak power increased to 43.7 kW. KTP when adjusting the tilt angle, first observed wavenumber of 154 cm-1 frequency shift. (the third chapter) (5), Cr4+: YAG tunable Q Nd:LGGG laser as the pump source, to achieve a variety of nonlinear effects of dual wavelength pumping, namely SRS and OPO exist at the same time, the maximum signal light the power is 448 mW, the pulse width of 850 PS, peak power of signal light is as high as 30.6 kW, single pulse energy is 26 J, and the dual wavelength rate equations of this process were studied. (third: Second) (6), for the first time with LD pumped C cut Nd, MgO:LiNbO3 crystal. Won the 1.47 W The continuous laser output, this is the first time exceeded W output, compared to the previous reported increase of at least 20 times. With KTP crystal to achieve the OPO 1.63 M signal light operation, the pulse width is 1.69 ns, the peak power of 11.4 kW, compared with the previously reported increased 3 times (third: third). (7) for the first time, the Yb:YAG 1050 nm laser pumped KTP high order Raman light output, pulse width and pulse width of three order Stokes is about 764 PS. Stokes light is 1.54 ns, the peak power is 3.5kW. and beam quality in two directions were 1.64 and 1.48, indicating that Stokes, the fundamental frequency light and the anti Stokes the optical gain coefficient have good effective Raman collinear.KTP is estimated to be 2.1 cm/GW. (third: fourth) (8), for the first time of KLM laser pumped intracavity OPO, AOM selection of mode-locked pulse high peak power, respectively using Nd:GGG and Nd:YVO4 laser pumped KTP bonding, the successful completion of the high peak power, Subnanosecond 1.57 M wave output signal of high energy: the highest peak power of KLM Nd:GGG/KTP OPO signal is 102 kW, KLM Nd:YVO4/KTP OPO, the minimum pulse width of the signal wave is about 120 PS, combined with the rate equation simulation experimental results. (Fourth: first, second) (9), with AO and Cr4+: YAG the main passive double loss QML laser as the pump cavity OPO, and the V cavity, in the case of diode pumped 8.25 W, the modulation period of AO was fixed at 1 ms (i.e. the repetition rate is 1 kHz) obtained the highest output signal energy is 96 J, the envelope width is 2.5 ns. when the acoustooptic switch frequency at 5 kHz when the power signal wave output reaches the maximum, up to 156 mW, is currently the QML laser pumped intracavity OPO optical signal of the maximum power output. At the same time, the beam quality factor M2 signal by measuring less than 1.5. (the fifth chapter) (10), using AO and Cr4+. YAG The main passive double loss technology, won the first single clamping pulse KTP OPO, when the diode pumped 10.5 W acousto optic switch frequency is 2 kHz, the minimum pulse width of the signal wave is 450 PS, the peak power is up to 35.5 kW, and study the relationship between the output signal wavelength and temperature, it is found that the signal wave length temperature rises 0.027 nm/ degrees of blue shift rate. At the same time to establish a set based on the rate equations of QML mode-locked pump IOPO, by numerical simulation, the pulse waveform and output energy basically agree with the experimental value. (fifth: Second) a new main points of the thesis are as follows: (1) for the first time, the use of single block KTP crystal to achieve high order Stokes optical and optical parametric oscillation of two kinds of nonlinear process, the beam quality factor M2 in about 1.2. (2) for the first time, stimulated Raman scattering and optical parametric oscillation, the double modulated Q laser pumped light output pulse width signal. For the first time the degree of compression of 580 PS. (3), the first to achieve a variety of nonlinear frequency conversion process of dual wavelength laser pumped, and established a set of coupled rate equations, the theoretical results and experimental results. (4) for the first time, the intracavity OPO pumped by KLM laser operation, to achieve high peak power the signal light output. (5), the first implementation of the intracavity OPO active passive double loss modulated QML laser pumped, to obtain a stable output sub nanosecond signal. (6), for the first time success of the single mode-locked laser pumped OPO pulse signal, pulse width is about 450 PS, the fluctuation mechanism combining Q lock the laser mode, establish the corresponding model. (7), a 1150 nm Yb:YAG/KTP three order Stokes light output, pulse width is about 764 PS, it is estimated that the effective Raman gain coefficient of KTP is 2.1 cm/GW. (8), for the first time to achieve the level of W Nd, MgO:LiNbO3 laser, and obtained 1630 NM Signal light.

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN248
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本文编号：1520067