Author Affiliations
Abstract
1 Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, China
In this paper, the frequency difference of the eigen polarization modes of the Nd:YAG crystal laser at different polarization ratios is experimentally studied, and to the best of our knowledge, the correlation between the frequency difference of the eigenmodes and the output polarization degree is reported for the first time. Combined with the analysis of the polarization beam profile, it is proved that the polarized laser produced by the isotropic crystal is due to the frequency locking of the eigen polarization modes. The weak birefringence in the crystal causes the round-trip phase difference of the orthogonal polarization modes, which leads to the frequency difference between the polarization modes. By the adjustment of the cavity mirror, the anisotropic loss will interact with the round-trip phase difference. The eigen polarization modes can reach frequency degeneration, and then be coherently combined to produce linearly polarized laser output. This work provides a useful reference for understanding the physical mechanism of polarized lasers realized by isotropic crystals.
linear polarization frequency difference weak birefringence Chinese Optics Letters
2023, 21(11): 111401
1 中国科学院福建物质结构研究所光电材料化学与物理重点实验室, 福建 福州 350002
2 中国科学院大学, 北京 100049
3 福州大学化学学院, 福建 福州 350108
精确的简并范围是运用横模频率简并原理产生结构光场的重要条件。本文基于激光频谱研究了共焦腔处于1/2简并态时激光横模频率简并的现象,并提出一种更准确的简并范围测量方法。实验中详细观测输出激光频谱信号随腔长的变化。利用频谱信息,实现了对腔内不同阶横模在发生简并时动力学行为变化的监测。研究结果表明,当腔内不同阶横模发生频率简并时,不同简并族的横模未因模式竞争被抑制,而是共存于腔内。同时,利用激光频谱随腔长的变化,实现了对简并范围更准确的测量。简并过程中重点监测的两个频率信号随着腔进入简并态合并成一个频率信号,该状态在一段腔长范围内稳定存在。据此测得更精确的简并范围,对应腔长约为0.20 mm。此外,对实验中测得的频谱信号进行理论对比,频谱信号的实验值与理论值基本吻合。
激光器 横模 频谱 简并 简并范围 中国激光
2021, 48(20): 2001003
Author Affiliations
Abstract
1 College of Chemistry, Fuzhou University, Fuzhou 350108, China
2 Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
3 Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, China
4 University of Chinese Academy of Sciences, Beijing 100049, China
5 Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Fuzhou 350108, China
The behavior of self-polarization emission in lasers has been proved in some cases. However, the degree and direction of polarization were often sensitive and unstable. We experimentally observed different beam profiles versus the angle of the polarizer relative to the polarization direction of the laser. In order to explore the polarization mechanism, the dynamics of intracavity polarized eigenmodes was analyzed theoretically. Simulative results were well consistent with our experimental observations. It indicated that the linear self-polarization emission was a composite state rather than an intrinsic state. This study contributed to the improvement of the polarization stability in passively Q-switched lasers.
self-polarization emission polarized eigenmodes coherent combination Chinese Optics Letters
2021, 19(2): 021401
