Steering of beam trajectory by distorted photonic crystals

TL;DR

This paper demonstrates how spatially distorted photonic crystals can steer electromagnetic beams in the terahertz range without changing the refractive index, enabling on-chip beam control through lattice distortion.

Contribution

It introduces a novel method of beam steering using lattice distortion in photonic crystals, verified experimentally in the terahertz range.

Findings

Beam steering achieved in terahertz using distorted photonic crystals.

Equifrequency contours analyzed to relate distortion and group velocity.

Experimental verification confirms theoretical predictions.

Abstract

Electromagnetic waves follow linear paths in homogenous index media, with the exception of band edges. In this study, we introduced spatially distorted photonic crystals (D-PCs) that are capable of beam-steering light waves, even when a homogeneous refractive index is maintained. We analyzed their equifrequency contours to investigate the correspondence between the direction of distortion and the direction of the group velocity vector in the D-PC. Thereafter, we experimentally verified the beam-steering phenomenon in the terahertz range using an all-silicon D-PC. Our structures serve as on-chip beam trajectory control without the need for any specially-engineered materials, using only lattice distortion.