Controlled generation of higher-order Poincare sphere beams from a laser
Controlled generation of higher-order Poincare sphere beams from a laser
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DOI：
10.1038/nphoton.2016.37
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发表时间：
2016-05-01
期刊：
影响因子：
35
通讯作者：
Forbes, Andrew
中科院分区：
文献类型：
--
作者：
Naidoo, Darryl;Roux, Filippus S.;Forbes, Andrew
光的角动量可以用高阶庞加莱球上的位置来描述，其中自旋和轨道角动量态的叠加产生了从显微镜到材料加工等许多应用的激光束。有许多技术可以制造这样的光束，但到目前为止还没有一种技术可以在源头上制造出这样的光束。本文报道了一种能够在高阶庞加莱球上产生所有态的新型激光器。我们利用激光腔内的几何相位控制将偏振映射到轨道角动量，证明了标准激光腔的轨道角动量简并可以被打破，产生纯轨道角动量光束，并且可以在源处产生高纯度的广义矢量涡旋光束。这项工作为基于腔内几何相位控制的新型结构光激光器铺平了道路。
The angular momentum of light can be described by positions on a higher-order Poincare sphere, where superpositions of spin and orbital angular momentum states give rise to laser beams that have many applications, from microscopy to materials processing. Many techniques exist to create such beams but none so far allow their creation at the source. Here we report on a new class of laser that is able to generate all states on the higher-order Poincare sphere. We exploit geometric phase control inside a laser cavity to map polarization to orbital angular momentum, demonstrating that the orbital angular momentum degeneracy of a standard laser cavity may be broken, producing pure orbital angular momentum beams, and that generalized vector vortex beams may be created with high purity at the source. This work paves the way to new lasers for structured light based on intracavity geometric phase control.