All-angle negative refraction effects and subwavelength imaging in photonic crystals with honeycomb lattice

摘要

Broadband, all-angle negative refraction (AANR) effects and imaging with subwavelength resolution have been analyzed in a honeycomb lattice of silicon rods in air background, as well as in the inverse structure of air holes in a silicon wafer. In the rod lattice, it was possible to obtain AANR effects for transverse-magnetic (TM) polarization in the second band (TM2) with a bandwidth as large as similar to 23% after optimizing the ratio of feature size to the lattice constant as 0.44 and a super-lensing effect with a binary coherent source resolution of 0.68.. On the other hand, the hole lattice shows AANR for both TM2 (bandwidth of 14%) and TE2 (bandwidth of 15.3%) bands with an additional advantage of polarization-independent AANR of 5% bandwidth. The hole lattice also shows a super- lensing behavior, which helps in imaging with a subwavelength resolution of 0.19 lambda for a single-point source and 0.80. with a binary source for TM polarization while it is 0.48 lambda and 0.97 lambda, respectively, for transverse-electric (TE) polarization. The conditions for perfect imaging have been studied, and the phenomenon of dual negative refraction for both TE and TM polarization is also discussed. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)