77‐4: Large Form Birefringence Realized by Dielectric Subwavelength Grating

Abstract

We present a detailed investigation of form birefringence realized by subwavelength grating based on high refractive index dielectric materials, e.g. titanium dioxide. The anticipated degree of birefringence is evaluated using Finite‐Difference Time‐Domain simulation of designed optical structure and in good accordance with the theoretical prediction. The designed subwavelength grating was fabricated using electron beam lithography and subsequent ICP dry etching technique on fused silica substrate. The artificial grating was then characterized under SEM and AFM, and a large birefringence 0.33 was obtained which can be furtherly improved with deposition process optimization.