Electrically Controlled Diffraction Grating in Azo Dye-Doped Liquid Crystals.

Chuen-Lin Tien,Rong-Ji Lin,Chi-Chung Kang,Chie-Tong Kuo,Shuan-Yu Huang,Bing-Yau Huang

doi:10.3390/polym11061051

Abstract

This research applies the non-linear effect of azo dye-doped liquid crystal materials to develop a small, simple, and adjustable beam-splitting component with grating-like electrodes. Due to the dielectric anisotropy and optical birefringence of nematic liquid crystals, the director of the liquid crystal molecules can be reoriented by applying external electric fields, causing a periodic distribution of refractive indices and resulting in a diffraction phenomenon when a linearly polarized light is introduced. The study also discusses the difference in the refractive index (Δn), the concentration of azo dye, and the rising constant depending on the diffraction signals. The experimental results show that first-order diffraction efficiency can reach ~18% with 0.5 wt % azo dye (DR-1) doped in the nematic liquid crystals.

Highlights

Diffraction grating is an optical element with periodic distribution of thicknesses or refractive indices, which can decompose and diffract optical waves
We present a prototype of electrically controllable diffraction gratings based on liquid crystals
Materials and Methods diffraction gratings demonstrated in this work were fabricated by injecting azo dye-doped liquid crystals into empty cellsdemonstrated with grating-like azo dye-doped liquid crystal was

Summary

Introduction

Diffraction grating is an optical element with periodic distribution of thicknesses or refractive indices, which can decompose and diffract optical waves. The diffracted direction depends on the periodic of thickness or refractive index of diffraction grating and the wavelength of the incident light [1]. With this feature, diffraction grating is an important component in optical spectroscopy [2]. ThePolymers diffraction efficiency of the tunable grating device can be further improved by doping a tiny amount of azo dye. When the concentration of dye exceeds a critical value, the diffraction efficiency a tiny amount of azo dye. When the concentration of dye exceeds a critical value, the decreases due to the excess dye molecules and the disturbance of liquid crystal orientations. Diffraction efficiency decreases due to the excess dye molecules and the disturbance of liquid crystal orientations

Materials and Methods

Results and Discussion

V is estimated

Diffraction

Conclusions