Twin optical vortices from Laguerre-Gaussian beam and methyl red doped nematic liquid crystal interaction

Abstract

Bound pair optical vortices (twin vortices) of opposing topological charge were seen when Laguerre-Gaussian (LG) beams of (0,2) and (0,3) modes were made to interact with a homeotropically aligned methyl red doped nematic liquid crystals (MR:NLC). Interferograms with forked-like discontinuities demonstrate the presence of these vortices. These vortices appear after a certain intensity onset. After the onset intensity, the vortices increased its topological charge with increasing LG beam intensity. A maximum phase differences of 4π and 6π were observed for incident LG (0,2) and LG (0,3) modes, respectively. These phase differences correspond to very large index change in the MR:NLC of 0.021 and 0.031.