二极管泵浦碟片激光器研究

发布时间：2018-02-28 05:19

本文关键词： Yb:YAG 吸收效率 24冲程平凹腔焊接　出处：《长春理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着半导体二极管泵浦激光器技术的不断发展和提高,LD泵浦的高功率Yb:YAG全固体碟片激光器因其具有优等的光学、化学、热力稳定性和机械性而得到广泛的关注。本文则做了以下几个方面的研究。(1)本文首先理论研究了Yb:YAG晶体的吸收效率和掺杂浓度、厚度之间的关系,并且用Lamda950分光光度计测量了晶体掺杂浓度为10%,厚度为0.3mm的吸收系数,验证了理论和模拟计算的一致性。最后通过测量得到的吸收系数,用Matlab模拟计算了在24冲程泵浦下晶体掺杂浓度为10%,厚度为0.3mm的吸收效率为96.4%(R=99.5%)。同时还对比分析了在不同泵浦功率下,969nm零声子线泵浦和940nm泵浦在晶体表面的温度差异。(2)通过Zemax软件设计了24冲程的泵浦结构,并通过阈值功率密度公式计算了7倍泵浦阈值功率密度时,泵浦光斑的大小为2.4mm。最后利用Zemax优化仿真得到当泵浦光斑为2mm时为最适宜。(3)利用Matlab软件分析了碟片激光器的直腔,最后分析得到在180W泵浦时由于晶体表面会产生形变,但是只要晶体曲率半径的形变量是腔长的2倍之上,整个激光器就是稳定的。通过比较最后选用腔长为L=105mm、R2=840mm的平凹腔,实现了36.21%的连续光输出;占空比为12.5%时,实现了61.3%的光光效率。(4)利用Lamda950分光光度计、美国zygo干涉仪和AFM分别测量了晶体、非球面和棱镜的透过率、表面面型和膜层的微观结构。最后分析得到各个模块的反射率都能够达到R=99.7%,面型都能够保持在1/8?之下,并且利用ANSYS软件模拟了晶体在180W泵浦时前后表面的温差,合理的设计了微通道的冷却系统、晶体和铜钨的焊接工艺。
[Abstract]:With the development of semiconductor diode pumped laser technology and the improvement of LD-pumped high power Yb:YAG all-solid-state disc laser, because of its excellent optical and chemical properties, Thermal stability and mechanical properties have attracted wide attention. In this paper, the following aspects have been studied. Firstly, the relationship between absorption efficiency and doping concentration and thickness of Yb:YAG crystals has been studied theoretically. The absorption coefficient of the crystal with doping concentration of 10 mm and thickness of 0.3 mm is measured by Lamda950 spectrophotometer, which verifies the agreement between the theory and the simulation calculation. The absorption efficiency of crystal doped with doping concentration of 10 and thickness of 0.3 mm under 24 stroke pumping was calculated by Matlab. The temperature difference of 969 nm zero phonon line pumping and 940 nm pump on the crystal surface was also compared and analyzed. The pump structure of 24 stroke is designed by Zemax software. With the formula of threshold power density, the size of pump spot is 2.4 mm when the power density of 7 times pump threshold is calculated. Finally, when the pump spot is 2 mm, the optimum value of pump spot is obtained by using Zemax. Finally, the straight cavity of disc laser is analyzed by Matlab software. Finally, it is found that the crystal surface will deform at 180W pump, but the whole laser is stable as long as the shape variable of the curvature radius of the crystal is more than 2 times the length of the cavity. The continuous light output of 36.21% is realized, the optical efficiency of 61.3% is realized when the duty cycle is 12.5) the transmittance of crystal, aspherical surface and prism are measured by zygo interferometer and AFM using Lamda950 spectrophotometer. Finally, the reflectivity of each module can reach R ~ (99. 7), and the surface shape can be kept at 1 / 8? The temperature difference between the front and back surfaces of the crystal pumped at 180W was simulated by using ANSYS software. The cooling system of the microchannel and the welding technology of crystal and copper tungsten were designed reasonably.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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