Tung J C, Chen B H, Sung C K
Opt Express. 2023 Nov 20;31(24):40836-40844. doi: 10.1364/OE.508108.
The criteria for achieving adjustable rotation of optical vortices are analyzed and used to design a diode-pumped solid-state laser that incorporates intracavity second harmonic generation within a concave-flat cavity to produce frequency-doubled Hermite-Gaussian (FDHG) modes. These FDHG modes are subsequently employed to generate various structured lights containing 2, 4, and 6 nested vortices using an external cylindrical mode converter. Through theoretical exploration, we propose that increasing the radius of curvature of the concave mirror and extending the cavity length can enhance the rotational angles of multiple vortices by expanding the adjustable range of phase shift for FDHG modes. Moreover, theoretical analyses assess vortex rotation concerning the positions of a nonlinear medium, successfully validating the experimental observations and elucidating the phase structures of the transformed beams.
分析了实现光学涡旋可调旋转的标准，并将其用于设计一种二极管泵浦固体激光器，该激光器在凹面-平面腔内集成了腔内二次谐波产生，以产生倍频厄米-高斯（FDHG）模式。随后，利用外部圆柱模式转换器，这些FDHG模式被用于产生包含2个、4个和6个嵌套涡旋的各种结构化光。通过理论探索，我们提出增大凹面镜的曲率半径并延长腔长，可以通过扩大FDHG模式的相移可调范围来增强多个涡旋的旋转角度。此外，理论分析评估了与非线性介质位置有关的涡旋旋转，成功验证了实验观察结果，并阐明了转换光束的相位结构。
