蓝光离轴泵浦Pr:YLF激光器及其高阶横模特性实验研究

Experimental Investigation on High-order Transverse-mode of the Pr:YLF Laser by a Blue Laser-diode Off-axis Pumping

采用蓝光二极管(LD)离轴泵浦Pr:YLF晶体和谐振腔调控,开展了直接输出720 nm激光的空心光束和高阶横模特性的理论和实验研究.基于高阶厄米-高斯光束(HG)光强特征理论,数值模拟了厄米-高斯光束(HG)与拉盖尔-高斯光束(LG)之间的模态转换特性.实验中,采用442 nm蓝光LD作为激光泵浦源,在紧凑的平凹谐振腔内使激光起振.通过LD离轴泵浦Pr:YLF晶体和谐振腔调节手段,直接获得空心和高阶HG模式的720 nm激光输出.同时,理论分析了HG模式相干叠加产生不同空间模态的光强分布,实验结果证实高阶HG光束与理论计算基本一致.本文方法在粒子操控、光学微加工和光通信等领域具有潜在应用价值.

The direct generation of the visible high-order transverse-mode laser was present by employing an off-axis pumping and cavity control in a diode end-pumped Pr:YLF laser.The detailed numerical analysis was proposed based on the intensity characteristic theory about the High-order Hermite-Gaussian(HG)beam and the coherent superposition of different HG amplitudes and phases.In our setup,a blue LD was served as an end-pumped source with a pump wavelength of 442 nm,and a compact plano-concave cavity was designed for lasing.For directly obtaining hollow and high-order HG mode 720 nm laser outputs,we manipulate the resonator of the Pr:YLF laser by employing an efficient off-axis diodepumping.The experimental results confirmed that the high-order HG beams are generally consistent with the theoretical calculations.In this paper,we experimentally demonstrated an approach for generating the hollow and high-order(HG)mode 720 nm laser beams by manipulating laser modes inside the cavity.Further researches will focus on obtaining higher energy high-order transverse-mode laser outputs,and the method in this paper has potential in the fields of optical manipulation,optical micromachining,and optical communications.