Broadband Tunable Photon-Pair Generation and Spectrum Measurement Based on Noncritical Lithium Niobate Crystals

TL;DR

This paper demonstrates a method to generate widely tunable near-infrared photon pairs using non-critical lithium niobate crystals, enabling broadband applications and gas spectroscopy with high coincidence-to-accidental ratios.

Contribution

It introduces a novel broadband tunable photon-pair source based on non-critical phase-matched lithium niobate crystals, expanding the wavelength range for quantum optics applications.

Findings

Photon pairs tunable from 800 to 1600 nm

High coincidence-to-accidental ratio (CAR > 20 dB)

Successful detection of CO gas absorption

Abstract

Photon pairs play a vital role in modern science, driving extensive research into their generation. Yet, the narrow phase-matching bandwidth of conventional crystals has largely confined studies to specific wavelengths, leaving research on broadband tunable sources underexplored. Here, we employ a non-critical phase-matched lithium niobate (LN) crystal to generate widely tunable photon pairs. The generated near-infrared (NIR) photon pairs exhibit a high coincidence-to-accidental ratio (CAR > 20 dB) and are tunable across the 800-1600 nm range. We further showcase the utility of NIR photon pairs in spectroscopy by detecting carbon monoxide (CO) gas absorption. This approach will facilitate the design of advanced LN-based photonic experiments.