Deterministic single photon subtraction with a cascade of waveguide-coupled atoms

Abstract

We present a specialized photon subtraction scheme that allows for the deterministic extraction of single photons from multiphoton states while preserving the input single-photon states unaltered. The proposed device integrates two Λ-type emitters with transitions selectively coupled to a single chiral waveguide through single photon Raman interaction (SPRINT). We develop a comprehensive theoretical model for the system using the input-output formalism within the SLH framework and conduct numerical simulations to analyze its interaction with traveling few-photon pulses of coherent light. We use these simulations to predict the scheme’s operation and highlight how this two-emitter extension improves the original SPRINT-based deterministic single-photon subtraction when it comes to implementing undetectable photon number splitting attack on a quantum key distribution channel.