Optical analogue of population trapping in the continuum: classical and quantum interference effects

TL;DR

This paper explores classical and quantum interference effects in optical waveguides coupled to a continuum, demonstrating an optical analogue of population trapping and predicting photon bunching phenomena.

Contribution

It introduces a quantum theory for light in coupled waveguides with a continuum, revealing classical trapping and quantum photon interference effects.

Findings

Classical light exhibits an optical analogue of population trapping.

Quantum effects include photon bunching during decay into the continuum.

Destructive interference leads to trapped states in the continuum.

Abstract

A quantum theory of light propagation in two optical channel waveguides tunnelling-coupled to a common continuum of modes (such as those of a slab waveguide) is presented, and classical and quantum interference effects are investigated. For classical light, the photonic system realizes an optical analogue of coherent population trapping in the continuum encountered in atomic physics, where destructive interference between different light leakage channels leads to the appearance of a trapped state embedded in the continuum. For nonclassical light, two-photon interference effects are predicted, such as the tendency of photon pairs to bunch when decaying into the continuum.