Generation of vortex beams from lasers with controlled Hermite- and Ince-Gaussian modes

We report selective excitations of higher-order Hermite-Gaussian and Ince-Gaussian (IG) modes in a laser-diode-pumped microchip solid-state laser and controlled generation of corresponding higher-order and multiple optical vortex beams of different shapes using an astigmatic mode converter (AMC). Simply changing the pump-beam diameter, shape, and lateral off-axis position of the tight pump beam focus on the laser crystal within a microchip semispherical cavity can produce the desired optical vortex beams in a well controlled manner. Pattern changes featuring different IG and HG modes obtained by rotating the AMC are also demonstrated. Numerical simulation shows that the vortex structure is changed by controlled off-axis laser diode pumping, which could lead toward precise optical manipulation of small particles. (C) 2008 Optical Society of America.

我们报道了在激光二极管泵浦的微片固体激光器中高阶厄米 - 高斯和因斯 - 高斯（IG）模式的选择性激发，以及使用像散模式转换器（AMC）对相应不同形状的高阶和多个光学涡旋光束的可控产生。只需改变微片半球形腔内紧聚焦泵浦光束在激光晶体上的泵浦光束直径、形状和横向离轴位置，就能以良好受控的方式产生所需的光学涡旋光束。还展示了通过旋转AMC获得的具有不同IG和HG模式的图案变化。数值模拟表明，通过控制离轴激光二极管泵浦可改变涡旋结构，这可能会朝着对微小粒子的精确光学操控发展。（C）2008美国光学学会