Highly efficient subwavelength imaging in mid-IR range using high dielectric hexagonal lattice photonic crystals

Abstract

Two-dimensional hole-type hexagonal lattice photonic crystals with low and high dielectric materials have been investigated for the aim of achieving all-angle negative refraction for subwavelength imaging. Structures composed of Si (eSi = 12 at IR) and PbTe (ePbTe = 36 at mid-IR) have been regarded, as sample materials. All-angle negative refraction has been achieved for the TM polarization in the second band under the light line in a broad bandwidth of 26% and 31% for low and high dielectric materials, respectively. The optimized radii for low and high dielectric PCs equal to 0.31a and 0.35a and provide the spatial full width at half maximum of 0.37λ and 0.38λ, respectively. The structures present TE gap in the operating wavelength range, and this feature of the structures can be applied to design polarization beam splitters in integrated space division multiplexing.