Multi-Mode Frequency Filtered Photon Correlations of a Driven Three-Level Ladder Atom

Resonance fluorescence and photon correlations are areas that have long been studied, and are integral to the field of quantum optics. Recently frequency filtered photon correlations and the method of frequency filtering have had a surge of interest [1]–[4]. In this work we develop a novel method of calculating frequency filtered photon correlations by coupling the atomic fluorescence - in this case, from a three-level ladder type atom [5], [6] - into an array of single-mode cavity filters. This coupling, modelled with an open cascaded systems approach [7], [8] is entirely unidirectional, allowing us to derive a closed set of coupled moment equations for the filter source operators. This provides an extremely efficient method for calculating frequency filtered second-order correlation functions.