Reconfigurable single photon sources based on functional materials

TL;DR

This paper explores a novel, reconfigurable single photon source based on functional materials that can dynamically change wavelength, enhancing quantum photonics applications especially in the mid-infrared spectrum.

Contribution

It introduces a method for dynamically repoling nonlinear crystals to actively control the wavelength of single photons generated via parametric downconversion.

Findings

Phase-matching conditions for pure single photon creation at 5-6 microns identified

Repoling of PMN-0.38PT material demonstrated at ambient conditions

Proposed approach enables on-flight wavelength switching of single photons

Abstract

The future of quantum photonic technology depends on the realization of efficient sources of single photons, the ideal carriers of quantum information. Parametric downconversion (PDC) is a promising route to create highly coherent, spectrally pure single photons for quantum photonics using versatile group-velocity matching (GVM) and tailored nonlinearities. However, the functionality to actively control the poling period of nonlinear crystals used in PDC is currently missing, yet would enable to dynamically modify the wavelength of single photons produced in the PDC process. Here a detailed GVM study is presented for functional PMN-0.38PT material which can be dynamically repolled at ambient conditions with fields as low as 0.4 kV/mm. Our study reveals phase-matching conditions for spectrally pure single photon creation at 5-6 microns. Further, a practical approach is proposed for on-flight wavelength switching of the created single photons. The reported reconfigurable functionality benefits a wide range of emerging quantum-enhanced applications in the mid-IR spectral region where the choice of single photon sources is currently limited.