Generation of optical vortex using smectic focal conic LC defect

Abstract

Phase singularity where the wave is rotating around and making point of zero intensity by destructive interference is called optical vortex. Optical vortex has attracted substantial interest in recent years with practical application such as microscopy, optical tweezer, quantum computing, and astronomical imaging. It is considered as a screw dislocation of wave due to its fundamental concept similar to that of crystal defect structure. There have been many efforts to make vortex-making devices including use of liquid crystal, spiral phase ramp, and conical laser cavity. But downsizing and large quantity production of vortex beam is still remained as hard issue to be resolved. The aim of this article is to generate micro-sized vortex beam from self-assembly of liquid crystal and investigate polarization properties with geometric vector interpretation in a simple way. We also demonstrated vortex beam array which is possible due to the self-organizing tendency of LC defects.