Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high pressure: Towards Bose-Einstein condensation of vacuum ultraviolet photons

TL;DR

This paper explores the extension of Bose-Einstein condensation of photons into the vacuum ultraviolet range using high-pressure noble gas mixtures as thermalization media, with experimental absorption spectra recorded.

Contribution

It presents experimental absorption spectra of xenon and ethylene-noble gas mixtures at high pressures near the vacuum ultraviolet regime, advancing photon BEC research.

Findings

Absorption spectra of xenon at 30 bar near 147 nm.

Spectra of ethylene-noble gas mixtures between 155 and 180 nm.

Progress towards Bose-Einstein condensation of VUV photons.

Abstract

Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of an experimental effort aiming at the extension of the concept of Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral regime, with gases at high pressure conditions serving as a thermalization medium for the photon gas. We have recorded absorption spectra of xenon gas at up to 30 bar gas pressure of the $5p^6 - 5p^56s$ transition with a wavelength close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 155 and 180 nm wavelength are reported.