全固态小型化紫外激光器研究
发布时间：2019-05-18 01:10
【摘要】：紫外激光具有波长短,易聚焦,分辨率高,光子能量大等特点而被广泛应用于激光雷达、激光通讯、激光标记和生物分子机制研究等方面。尽管LD(LaserDiode)泵浦的固体紫外激光器已经出现了一些实用化的装置,但是在实际中还面临光束质量较差,激光器功率稳定性不足,通过水冷控制温度导致激光器体积较大,使用不方便等问题。本论文旨在改善紫外激光器的稳定性,减小激光器体积,改善光束质量,同时提高可靠性和使用寿命,使激光器能够满足实用化要求,具体工作如下：(1)对LD泵浦调Q激光器进行了分析,由调Q原理结合四能级速率方程推得调Q激光器速率方程。同时根据三波互作用的耦合波方程,对频率转换等非线性过程、效率以及相位匹配过程进行了理论分析。(2)采用LD端面泵浦Nd:YVO4晶体产生基频光,LiB3O5 (LBO)晶体进行倍频与和频,声光调Q产生巨脉冲,比例积分微分算法(PID, Proportion Integration Differentiation)控制精确温度调节,补偿非线性晶体角度相位匹配误差,实现了一台输出波长为355nm的小型紫外激光器。该激光器在重复频率为15kHz,泵浦功率为13.33W时,355nm激光平均输出功率为1.24W,808nm-355nm的转换效率为9.3%,输出激光脉冲宽度为9.8ns,光束质量因子Mx2和My2分别为1.8和1.7,该激光器2小时内输出功率不稳定度为0.45%。(3)采用LD端面泵浦Nd:YVO4晶体产生基频光,LBO晶体进行倍频,BaB2O4 (BBO)晶体进行四倍频,声光调Q产生巨脉冲,实现了输出波长为266nm的激光器。该激光器在重复频率为15kHz,泵浦功率为12.58W时,266nm平均功率为440m W,脉冲宽度为10.7ns。该激光器采用多镜腔结构,通过多次反射倍频激光与四倍频激光,补偿由于BBO晶体走离效应产生的光斑不均匀性,使出射光斑接近圆斑。(4)采用LD端面泵浦Nd:YAG晶体,LBO晶体进行倍频,KD2PO4 (DKDP)晶体进行四倍频,Cr4+:YAG晶体调Q产生巨脉冲,实现了输出波长为266nm的激光器。实验中采用的DKDP晶体尺寸为10×10×20mm3,氘元素含量为98%,非线性过程采用Ⅰ类温度相位匹配方法。该激光器在重复频率为10Hz,泵浦功率为60W,泵浦脉宽为500μs时,获得266nm激光输出能量为57μJ、266nm激光脉冲宽度为亚纳秒量级。
[Abstract]:Ultraviolet laser has been widely used in lidar, laser communication, laser labeling and biomolecule mechanism because of its long wave length, easy focusing, high resolution and large photonic energy. Although some practical devices have appeared in the solid-state ultraviolet laser pumped by LD (LaserDiode), in practice, the beam quality is poor, the power stability of the laser is insufficient, and the volume of the laser is larger due to the control of temperature by water cooling. It is inconvenient to use and so on. The purpose of this paper is to improve the stability of ultraviolet laser, reduce the volume of laser, improve the beam quality, and improve the reliability and service life, so that the laser can meet the practical requirements. The specific work is as follows: (1) the LD pumped Q-switched laser is analyzed, and the rate equation of Q-switched laser is derived from the Q-switching principle combined with the four-level rate equation. At the same time, according to the coupling wave equation of three-wave interaction, the nonlinear processes, such as frequency conversion, efficiency and phase matching process are analyzed theoretically. (2) the fundamental frequency light is generated by LD end-pumped Nd:YVO4 crystal. The frequency doubling and sum frequency of LiB3O5 (LBO) crystal is carried out, and the giant pulse is generated by acousto-optic Q-switching. The proportional integral differential algorithm (PID, Proportion Integration Differentiation) controls the accurate temperature adjustment and compensates the angle and phase matching error of nonlinear crystal. A small ultraviolet laser with output wavelength of 355nm is realized. When the repetition rate is 15kHz and the pump power is 13.33W, the average output power of 355nm laser is 1.24W, the conversion efficiency of 808nm 鈮，
本文编号：2479546
[Abstract]:Ultraviolet laser has been widely used in lidar, laser communication, laser labeling and biomolecule mechanism because of its long wave length, easy focusing, high resolution and large photonic energy. Although some practical devices have appeared in the solid-state ultraviolet laser pumped by LD (LaserDiode), in practice, the beam quality is poor, the power stability of the laser is insufficient, and the volume of the laser is larger due to the control of temperature by water cooling. It is inconvenient to use and so on. The purpose of this paper is to improve the stability of ultraviolet laser, reduce the volume of laser, improve the beam quality, and improve the reliability and service life, so that the laser can meet the practical requirements. The specific work is as follows: (1) the LD pumped Q-switched laser is analyzed, and the rate equation of Q-switched laser is derived from the Q-switching principle combined with the four-level rate equation. At the same time, according to the coupling wave equation of three-wave interaction, the nonlinear processes, such as frequency conversion, efficiency and phase matching process are analyzed theoretically. (2) the fundamental frequency light is generated by LD end-pumped Nd:YVO4 crystal. The frequency doubling and sum frequency of LiB3O5 (LBO) crystal is carried out, and the giant pulse is generated by acousto-optic Q-switching. The proportional integral differential algorithm (PID, Proportion Integration Differentiation) controls the accurate temperature adjustment and compensates the angle and phase matching error of nonlinear crystal. A small ultraviolet laser with output wavelength of 355nm is realized. When the repetition rate is 15kHz and the pump power is 13.33W, the average output power of 355nm laser is 1.24W, the conversion efficiency of 808nm 鈮，
本文编号：2479546
本文链接：https://www.wllwen.com/kejilunwen/dianzigongchenglunwen/2479546.html
