Single-photon time-dependent spectra in coupled cavity arrays

TL;DR

This paper develops a method combining input-output formalism and quantum trajectories to analyze the time-dependent spectra of single photons in coupled cavity arrays, revealing how certain frequency components are trapped and delayed.

Contribution

It introduces a novel approach to compute the time-dependent spectrum of single photons in coupled cavities, including their generation process.

Findings

Certain frequency components of single photons are trapped inside cavities.

The method provides a physically intuitive description of photon propagation.

Time delays in photon wavepackets are directly linked to cavity trapping.

Abstract

We show how the input-output formalism for cascaded quantum systems combined with the quantum trajectory approach yields a compact and physically intuitive description of single photons propagating through a coupled cavity array. As a new application we obtain the time-dependent spectrum of such a single photon, which directly reflects the fact that only certain frequency components of single-photon wavepackets are trapped inside the cavities and hence are delayed in time. We include in our description the actual generation of the single photon, by assuming we have a single emitter in one of the resonators.