Low coherence-induced resonance in double-layer structures having parity-time symmetry

TL;DR

This paper demonstrates that low spatial coherence sources can induce significant resonance effects in double-layer parity-time symmetric structures, with resonance peaks diminishing as coherence increases.

Contribution

It provides simple formulas for transmittance and reflectance of Gaussian-Schell beams and reveals the impact of spatial coherence on resonance phenomena in PT-symmetric structures.

Findings

Low coherence sources cause large resonance peaks in transmission and reflection.

Resonance peaks decrease as the spatial coherence of the source increases.

The formalism applies to stratified dielectric structures with PT symmetry.

Abstract

We derive simple formulae for the transmittance $T$ and reflectance $R$ of Gaussian-Schell beams incident upon any stratified dielectric structure by using second-order classical coherence theory in the space-frequency picture. The formalism is applied to a particular structure consisting of a double-layer, with balanced gain and loss, satisfying the parity-time symmetry conditions. It is shown that sources with a low degree of spatial coherence, on the order of the wavelength, can induce large resonant peaks in the transmitted and reflected amplitudes. The resonance peaks vanish as the spatial coherence increases.