【作者】 胡春华；

【导师】 李桂秋；

【作者基本信息】 山东大学 ， 光学工程， 2011， 硕士

【摘要】 激光二极管(LD)泵浦的固体激光器具有高稳定性、高效率、高能量的优点,被广泛应用于军事、工业、医学和科学研究等领域,已成为国内外激光器领域研究的热点。1.34μm波长附近的激光由于与硅光纤低色散和低损耗的波长一致,所以与光通信中广泛采用的硅光纤传输窗口相吻合,而且它的倍频又是得到红色激光的有效途径,因此1.34μm区域的激光在激光医学、光纤通信、光传感定位和中红外参量振荡的抽运源等领域有着广阔的应用前景。Nd:Gd0.63Y0.37VO4晶体是一种新型的掺Nd晶体,研究表明该晶体在1.06μm被动调Q方面具有非常好的性能。本论文从理论和实验两个方面系统研究了Nd:Gd0.63Y0.37VO4晶体作为激光工作物质的1.34μm及红光激光特性,并首次测量了Nd:Gd0.63Y0.37VO4晶体的热焦距和被动损耗。我们使用光纤耦合的半导体激光器作为泵浦源,采用V3+:YAG饱和吸收体被动调Q方式对Nd:Gd0.63Y0.37VO4晶体1.34μm和KTP内腔倍频0.67μm激光特性进行了实验测量。通过实验显示了Nd:Gd0.63Y0.37VO4晶体作为激光工作物质的一些优良特性。论文的主要内容概括如下：1、实验研究了Nd:Gd0.63Y0.37VO4晶体的热焦距及被动损耗；2、实验研究了LD泵浦Nd:Gd0.63Y0.37VO4晶体1.34μm连续激光输出特性；3、采用平-凹腔结构,在不同输出镜透过率下,对LD泵浦Nd:Gd0.63Y0.37VO4晶体V3+:YAG被动调Q激光特性进行了实验研究,在V3+:YAG小信号透过率为96%、泵浦功率为5.04W、输出镜透过率T=5%时获得了61.4ns的最短脉宽。利用速率方程理论对该激光器进行了理论分析,理论计算与实验结果相符；4、采用平-凹腔设计,在不同输出镜透过率、不同调制重复频率下,对LD泵浦Nd:Gd0.63Y0.37VO4晶体声光调Q激光特性进行了实验研究,当调制重复频率为10kHz、输出镜透过率T=5%、泵浦功率为4.45W时,获得了最短脉宽45.6ns、最大单脉冲能量32.6μJ和最高峰值功率715W的主动调Q脉冲输出；5、采用三镜折叠腔,实验研究了LD泵浦Nd:Gd0.63Y0.37VO4晶体、KTP内腔倍频0.67μm红光激光器连续输出特性；6、采用三镜折叠腔,利用腔内倍频方法,实验研究了LD泵浦Nd:Gd0.63Y0.37VO4/KTP、V3+:YAG饱和吸收体被动调Q激光器红光输出特性,当V3+:YAG小信号透过率T0=89%、泵浦功率为4.1W时,获得了125ns的最短脉宽、4.3μJ的最大单脉冲能量和34.4W的最高峰值功率,并从理论上进行了数值分析,理论计算值和实验结果基本一致。论文的主要创新点：1、首次研究了Nd:Gd0.63Y0.37VO4晶体的热焦距及被动损耗；2、利用LD端面泵浦方式,采用平-凹腔,首次从理论和实验上研究了V3+:YAG饱和吸收体被动调Q Nd:Gd0.63Y0.37VO4晶体1.34μm激光输出特性,理论计算和实验结果相符；3、采用三镜折叠腔,利用腔内倍频方法,首次实现了LD泵浦Nd:Gd0.63Y0.37VO4/KTP 0.67μm红光激光器的连续运转及V3+:YAG饱和吸收体被动调Q运转,并从理论上进行了数值分析,理论计算值和实验结果基本一致。更多还原

【Abstract】 In recent several years, there has been an increasing interest in laser-diode (LD) pumped all-solid-state lasers because such lasers can be widely used in the fields of military affairs, industry, medicines and so on. The wavelength of 1.34μm laser is identical with the low dispersion and low loss wavelength of silicon optical fiber. Therefore, it coincides with the transmission window of silicon optical fiber and the frequency-doubling of these lasers supplies an effective way to generate red lasers. So there are widespread application fields for the lasers operating nearby 1.34μm in laser medicine, optical fiber communication, optical sensing locating and the pump source of mid-infrared optical parametric oscillation.Nd:Gd0.63Y0.37VO4 is a new one in the class of Nd-doped mixed vanadate crystals. It has been proved to be a good laser gain medium for 1.06μm Q-switched operation. In my study, we have analyzed the Nd:Gd0.63Y0.37VO4 laser performance experimentally and theoretically, and for the first time, measured the thermal focal length and passive loss of Nd:Gd0.63Y0.37VO4 crystal. By fiber-coupled laser-diode being used as the pump source and V3+:YAG saturable absorber as the Q-switch, the Nd:Gd0.63Y0.37VO4 laser with wavelength of 1.34μm and Nd:Gd0.63Y0.37VO4 red laser with wavelength of 0.67μm have both been realized. Through the experimental research, we get the excellent characteristics of Nd:Gd0.63Y0.37VO4 crystal as laser medium in this paper.The main contents of this dissertation include:1. The thermal focal length and passive loss of Nd:Gd0.63Y0.37VO4 crystal have both been researched;2. The LD-pumped CW characteristics of Nd:Gd0.63Y0.37VO4 laser at 1.34μm have been researched;3. Using short plane-concave cavity, we have got the characteristics of the LD-pumped passively Q-switched Nd:Gd0.63Y0.37VO4 laser with V3+:YAG saturable absorber at different output transmissions. With the V3+:YAG initial transmission of 96%, the pump power of 5.04W and the output transmission of T=5%, the shortest pulse with width of 61.4ns is obtained. By using the rate-equation theory, we have analyzed the laser performance and the theoretical calculations agree with the experimental data;4. Using plane-concave cavity, we have got the characteristics of the LD-pumped actively Q-switched Nd:Gd0.63Y0.37VO4 laser with AO modulator at different output transmissions and different modulation repetition rates. With the modulation repetition rate of 10kHz, the output transmission of T=5%and the pump power of 4.45W, the actively Q-switched pulses with the shortest pulse width of 45.6ns, the largest single pulse energy of 32.6μJ and the highest peak power of 715W are achieved;5. With the three-mirror-folded laser cavity, the CW output characteristics of the LD-pumped Nd:Gd0.63Y0.37VO4/KTP 0.67μm red laser are given;6. With the three-mirror-folded cavity, we have got the characteristics of the LD-pumped passively Q-switched Nd:Gd0.63Y0.37VO4/KTP red laser with V3+:YAG saturable absorber. When the V3+:YAG initial transmission To is 89%and the pump power is 4.1W, the shortest pulse width of 125ns with the largest single pulse energy of 4.3μJ and the highest peak power of 34.4W is obtained. The theoretical calculations of the rate equations are consistent with the experimental results.The main innovations of this dissertation are as follows:1. We firstly research the thermal focal length and passive loss of Nd:Gd0.63Y0.37VO4 crystal;2. Using LD end-pumping, we have experimentally and theoretically studied the performance of the passively Q-switched Nd:Gd0.63Y0.37VO4 laser with V3+:YAG saturable absorber in a planar-concave cavity for the first time, and the theoretical calculations are accord with the experimental data;3. With the three-mirror-folded cavity, we firstly present the performance of the LD-pumped intracavity-frequency-doubling Nd:Gdo.63Yo.37V04/KTP 0.67μm red laser operating in CW regime, as well as in the passive Q-switching regime with V3+:YAG, respectively. We have also given the rate-equation model to analyze the laser characteristics and the theoretical predictions are in agreement with the experimental results.更多还原