Generation of doughnutlike vortex beam with tunable orbital angular momentum from lasers with controlled Hermite-Gaussian modes.
This study demonstrates successive higher-order Hermite-Gaussian (HG(0,m)) mode operations in a microchip solid-state laser with a controlled off-axis laser diode (LD) pumping and generation of the corresponding doughnutlike laser beam of tunable ring diameter and orbital angular momentum, by experimentally focusing a Hermite-Gaussian mode (HGM) lasing beam into an astigmatic mode converter (AMC) with a mode-matching lens. Based on the successful generation of stable doughnutlike vortex beams by combining the LD off-axis pumping of microchip lasers and an AMC, this study proposes a design for a compact, solid doughnutlike vortex laser beam generator that combines three elements (i.e., laser cavity, mode-matching lens, and AMC) into one practical device. The desired doughnutlike vortex beam with different orbital angular momentum is easily generated by simply controlling the lateral off-axis pump position and pump beam shape on the laser crystal by numerical simulation.
Chu
Shu-Chun
SC
Department of Physics, National Cheng Kung University, Tainan City, Taiwan. scchu@mail.ncku.edu.tw
Ohtomo
Takayuki
T
Otsuka
Kenju
K
D003198:Computer Simulation; D003460:Crystallization; D004867:Equipment Design; D007834:Lasers; D008027:Light; D015233:Models, Statistical; D016011:Normal Distribution; D055095:Optics and Photonics; D012107:Research Design; D012542:Scattering, Radiation