High-efficiency antireflection structures for terahertz self-collimating photonic crystals

Abstract

We present two types of antireflection structures for two-dimensional photonic crystals of square lattice air holes in silicon, which are embedded in homogeneous background media. One type consists of rows of air holes, and the other consists of air slots that are introduced into the photonic crystal interfaces. The finite-difference time-domain simulations show that the terahertz waves couple efficiently into and out of the self-collimating photonic crystals with the designed antireflection structures applied. The proposed antireflection structures can bring significant improvements in coupling efficiency for compact terahertz devices based on self-collimating photonic crystals. (C) 2009 Optical Society of America