Abstract

Optical vortices are attracting much attention because of their applications in various fields of optical processing, communications, enhanced imaging systems, and bio-inspired devices. Different methods to generate optical vortices have been devised to date. Among them, several are based on the exploitation of light–matter interaction in liquid-crystal media.This talk focuses on the mechanisms of vortex generation in liquid crystals, in particular on vortex generation induced by umbilics, that is, defects arising in homeotropically aligned nematic cells, which act as topological matter templates able to realize the conversion from spin to the orbital angular momentum of an incoming Gaussian beam. Optical vortex induction in a photosensitive light valve is presented as a self-stabilizing mechanism leading to reconfigurable and programmable vortex arrays. On each lattice site, every matter vortex acts as a photonic spin-to-orbital momentum coupler, converting input arrays of circularly polarized beams into output arrays of vortex beams with topological charges consistent with the matter lattice symmetry.

 

WebEx Link: https://nationaltaiwanuniversity-ksz.my.webex.com/nationaltaiwanuniversity-ksz.my/j.php?MTID=m7b50dd77844601a86ac9b3e9b286876c

Meeting number (access code): 2515 130 0436

Meeting password: VYfmCh6n9r3

 

Organizers: Chueh-Hsin Chang (CCU), Jia-Yuan Dai (NTHU), Bo-Chih Huang (CCU), Chih-Chiang Huang (CCU), Alejandro López-Nieto (NTU), Chang-Hong Wu (NYCU)