Dynamic stimulated emission for deterministic addition and subtraction of propagating photons

TL;DR

This paper introduces a dynamic stimulated emission method enabling deterministic, high-fidelity addition and subtraction of single photons to propagating modes, advancing quantum state engineering beyond traditional probabilistic techniques.

Contribution

The authors present a novel dynamic stimulated emission approach for deterministic photon addition and subtraction, with semi-analytic solutions for Fock and superposition states, enhancing quantum optics capabilities.

Findings

Achieved >0.996 fidelity for deterministic photon subtraction and addition.

Demonstrated preparation of Schrödinger cat states from squeezed vacuum.

Enabled high-probability addition of photons to squeezed and displaced states.

Abstract

Photon subtraction and addition are essential non-Gaussian processes in quantum optics, where conventional methods using linear optics and number-resolving detection often suffer from low success probability. Here, we introduce the concept of \textit{dynamic stimulated emission}, whereby a quantum emitter undergoes stimulated emission with a time-dependent coupling. We show that, for both two- and three-level emitters, this process can be used to deterministically add or subtract a photon to a single propagating optical mode. We provide semi-analytic solutions to this problem for Fock states, enabling deterministic and unconditional single-photon subtraction and addition with fidelity ${\cal F}>0.996$. Our semi-analytic solutions are provided for both dynamically coupled two-level systems and for three-level systems whose dynamical coupling is controlled by a coherent laser drive. Moving beyond individual Fock states, we further showcase the ability to subtract and add single photons to photon-number superposition states. We show that Schr\"{o}dinger cat states can be prepared from squeezed vacuum input via cascaded subtraction or cascaded addition. Finally, we show that our photon-addition process can be used to add a photon to any squeezed and displaced state with high success probability and fidelity ${\cal F}>0.99$, thereby potentially converting quantum emitters from single-photon sources to sources of single-photon-added Gaussian states without the need for inline squeezing. Our protocols provide a path towards integrating quantum emitters to construct efficient sources of single-mode non-Gaussian light beyond single photons.