How to optimize the absorption of two entangled photons

TL;DR

This paper explores how entangled photon pairs can be optimized to significantly enhance two-photon absorption in a three-level system, comparing quantum and classical pulse strategies under realistic experimental conditions.

Contribution

It introduces a method to optimize entangled photon states for maximum absorption enhancement, incorporating practical constraints like pulse shaping and local operations.

Findings

Entanglement can substantially increase two-photon absorption efficiency.

Optimal pulse shaping functions are derived for experimental implementation.

Maximum enhancement surpasses that of classical, separable pulses.

Abstract

We investigate how entanglement can enhance two-photon absorption in a three-level system. First, we employ the Schmidt decomposition to determine the entanglement properties of the optimal two-photon state to drive such a transition, and the maximum enhancement which can be achieved in comparison to the optimal classical pulse. We then adapt the optimization problem to realistic experimental constraints, where photon pairs from a down-conversion source are manipulated by local operations such as spatial light modulators. We derive optimal pulse shaping functions to enhance the absorption efficiency, and compare the maximal enhancement achievable by entanglement to the yield of optimally shaped, separable pulses.