基于纯相位空间光调制器和棋盘相格法制备高阶贝塞尔涡旋光束

Generation of High-Order Bessel Beam Vortex Based on Phase-Only Spatial Light Modulator and Checkerboard Phase Lattice Method

当前,较为常用的光场复振幅调制方法主要是通过衍射效应来实现的,这造成了能量利用效率普遍较低,为此基于纯相位空间光调制器(SLM)和棋盘相格法在衍射零级实现了高阶贝塞尔涡旋光束的制备。首先,介绍了奈奎斯特光栅和棋盘相格法的基本原理,推导了在衍射零级制备贝塞尔涡旋光束的复振幅调制方法并编码了相应的全息图,分别模拟了通过该方法生成的低阶和高阶贝塞尔涡旋光束的光场分布。其次,基于纯相位SLM搭建了相应的实验光路,分别制备了低阶和高阶贝塞尔涡旋光束。最后,讨论了本文方法的优点和不足。实验结果表明,本文方法制备的高阶贝塞尔涡旋光束的模式纯度虽然不及衍射一级,但却可以将衍射效率提升约4.5倍。

At present,the commonly used complex amplitude modulation method of light field is mainly realized by diffraction effect,which results in low energy utilization efficiency.Therefore,based on the phase-only spatial light modulator(SLM)and checkerboard phase lattice method,the generation of high-order Bessel vortex beam at zeroth-order of diffraction is realized.First,the basic principles of the Nyquist grating and checkerboard phase lattice method are introduced,the complex amplitude modulation method for generation of Bessel vortex beam at zeroth-order of diffraction is derived,and the corresponding hologram is coded.The light field distributions of low-order and high-order Bessel vortex beams generated by this method are simulated respectively.Then,the corresponding experimental optical paths are built based on the phase-only SLM,and the low-order and high-order Bessel vortex beams are prepared respectively.Finally,the advantages and disadvantages of this method are discussed.The experimental results show that the mode purity of the high-order Bessel vortex beam generated by this method is not as good as that of the first-order diffraction,but the diffraction efficiency can be increased by about 4.5 times.