Affiliation:
1. Liquid Crystals and Photonics Group Department of Electronics and Information Systems Ghent University Technologiepark‐Zwijnaarde 126 Ghent 9052 Belgium
2. Faculty of Advanced Technology and Chemistry Military University of Technology Warsaw 00–908 Poland
Abstract
AbstractDiffractive optical elements (DOEs) are increasingly used as lightweight and compact solutions in photonic devices. Steering of light and manipulation of the polarization can be efficiently obtained with the help of photo‐aligned liquid crystal (LC) devices. 1D LC diffraction gratings are studied that are based on the geometric phase principle and demonstrate that the optical functionality can be substantially broadened by using dual frequency LC. Switching between a highly efficient diffractive and a transmissive state is obtained by adjusting the frequency of the applied electric field. Compared to commonly studied 1D nematic LC diffraction gratings, the steering efficiency over large diffraction angles is strongly increased. By using an appropriate electric‐field treatment, the efficiency for first‐order diffraction of red light over an angle of 12.6° increases from 60% to 90%. Moreover, additional switching phenomena are observed at intermediate voltage treatments, leading to enhanced tunability of the DOEs. The origin of this behavior is explained with the help of finite element Q‐tensor simulations for the director configuration.
Funder
Wojskowa Akademia Techniczna
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials