Tunable fiber source of entangled UV-C and infrared photons

TL;DR

This paper demonstrates a tunable fiber-based source of entangled photon pairs spanning ultraviolet and infrared wavelengths, enabling new quantum applications in spectroscopy and sensing.

Contribution

It introduces a novel method using four-wave mixing in xenon-filled photonic crystal fibers to generate and tune entangled biphotons across a wide spectral range.

Findings

Ultraviolet photons tunable from 271 nm to 235 nm.

Infrared photons tunable from 764 nm to 1342 nm.

Tuning achieved by adjusting gas pressure by only 0.57 bar.

Abstract

Pairs of entangled photons -- biphotons -- are indispensable in quantum applications. However, some important spectral ranges, like ultraviolet, have been inaccessible to them so far. Here, we use four-wave mixing in a xenon-filled single-ring photonic crystal fiber to generate biphotons with one of the photons in the ultraviolet and its entangled partner in the infrared spectral range. We tune the biphotons in frequency by varying the gas pressure inside the fiber and thus tailoring the fiber dispersion landscape. The ultraviolet photons are tunable from 271 nm to 235 nm and their entangled partners, from 764 nm to 1342 nm, respectively. The tunability up to 170 THz is achieved by adjusting the gas pressure by only 0.57 bar. At 1.32 bar, the photons of a pair are separated by more than 2 octaves. The access to ultraviolet wavelengths opens the possibility for spectroscopy and sensing with undetected photons in this spectral range.