Generation of optical vortices using a uniaxially aligned azo-dye-doped liquid crystal cell and space-variant polarization projection system.

A scheme is presented for an optical vortex (OV) generator comprising a uniaxially aligned azo-dye-doped liquid crystal (ADDLC) and a space-variant polarization projection (SVPP) system. The SVPP system consisting of an electro-optic modulator and a micro-electromechanical system projects a time-averaged SVP field equal to a vector beam onto the ADDLC and fabricates a three-dimensional twisted anisotropic structure, which has spatial phase modulation properties from plane to helical shape. The generation of OVs with odd- and even-numbered topological charge is experimentally demonstrated. As a flexible and broadband spatial light modulator, the proposed scheme should be applicable to the research and development of OV applications.