Geometric optics of Bloch waves in a chiral and dissipative medium

TL;DR

This paper develops a geometric optics theory for wave transport in chiral, dissipative periodic media, revealing new terms and fields influencing particle dynamics beyond traditional models.

Contribution

It introduces additional terms and fields in the equations of motion for particles in chiral, dissipative media, extending previous geometric optics theories.

Findings

New terms in particle equations of motion identified

Additional fields like angular momentum and dissipation dipole included

Theory applied to light in photonic crystals

Abstract

We present a geometric optics theory for the transport of quantum particles (or classical waves) in a chiral and dissipative periodic crystal subject to slowly varying perturbations in space and time. Taking account of some properties of particles and media neglected in previous theory, we find important additional terms in the equations of motion of particles. The (energy) current density field, which traces the geometric optics rays, is not only governed by the Bloch band energy dispersion but also involves there additional fields. These are the angular momentum of the particle, the dissipation dipole density, and various geometric gauge fields in the extended phase space spanned by space-time and its reciprocal, momentum and frequency. For simplicity, the theory is presented using light propagation in photonic crystals.