Photon Correlations Generated by Inelastic Scattering in a One-Dimensional Waveguide Coupled to Three-Level Systems

TL;DR

This paper investigates photon correlations resulting from inelastic scattering in one-dimensional waveguides coupled to three-level systems, revealing enhanced non-classical correlations near EIT conditions due to interference effects and slow-light phenomena.

Contribution

It introduces a two-photon scattering approach linking photon correlations with inelastic scattering in 3LS systems, highlighting effects beyond EIT.

Findings

No inelastic scattering at EIT resonance.

Enhanced inelastic flux and correlations away from EIT.

Observation of long-time-scale photon bunching.

Abstract

We study photon correlations generated by scattering from three-level systems (3LS) in one dimension. The two systems studied are a 3LS in a semi-infinite waveguide (3LS plus a mirror) and two 3LS in an infinite waveguide (double 3LS). Our two-photon scattering approach naturally connects photon correlation effects with inelastically scattered photons; it corresponds to input-output theory in the weak-probe limit. At the resonance where electromagnetically induced transparency (EIT) occurs, we find that no photons are scattered inelastically and hence there are no induced correlations. Slightly away from EIT, the total inelastically scattered flux is large, being substantially enhanced due to the additional interference paths. This enhancement carries over to the two-photon correlation function, which exhibits non-classical behavior such as strong bunching with a very long time-scale. The long time scale originates from the slow-light effect associated with EIT.