Cross Feshbach resonance

TL;DR

This paper demonstrates a cross Feshbach resonance in semiconductor microcavities, enabling efficient conversion of polariton pairs into entangled photon pairs, advancing quantum photonics applications.

Contribution

It introduces the concept of a cross Feshbach resonance involving upper and lower polaritons coupled to a biexciton, a novel mechanism for entangled photon generation.

Findings

Existence of cross Feshbach resonance in semiconductor microcavities.

Efficient conversion of polariton pairs into entangled photons.

Potential for generating momentum and polarization entangled photon pairs.

Abstract

Feshbach resonance occurs when a pair of free particles is resonantly coupled to a molecular bound state. In the field of ultracold quantum gases, atomic Feshbach resonances became a usual tool for tailoring atomic interactions opening up many new applications in this field. In a semiconductor microcavity, the Feshbach resonance appears when two lower polaritons are coupled to the molecular biexciton state. Here, we demonstrate the existence of a cross Feshbach resonance for which a pair of polaritons, lower together with upper, effectively couples to the biexciton state. This demonstration is a crucial step towards the efficient generation of entangled photon pairs in a semiconductor microcavity. The existence of a Cross Feshbach resonance establishes the condition to convert a pair of upper and lower polaritons via the biexciton state into two lower polaritons, paving the way for the generation of momentum and polarization entangled photons.