Analyzing air pollution with correlated photon pairs

About this event

This event is a ~1h advanced seminar from Prof Jean-Pierre Wolf in the Stückelberg auditorium. The event is followed by an aperitif.

Abstract

In recent years, quantum Fourier transform infrared (QFTIR) spectroscopy has emerged as an alternative to conventional absorption spectroscopy
in the mid-infrared. By harnessing induced coherence and spectral correlations of photon pairs in a nonlinear Michelson interferometer, this technique
offers promising potential for the practical detection of organic gases. We first built a nonlinear Michelson interferometer
with 1.7 m-long arms to increase the absorption length, coupled with analysis techniques from classical differential absorption spectroscopy used for gas traces
detection. With this set-up we could perform the accurate identification of mixtures of fugitive emissions of organic solvents released in ambient air. We then developed
a new disruptive method (patent pending) allowing to extend the absorption at will and thus allow sensitivity beyond state of the art conventional FTIR and successfully tested
it on a 45 m path of ambient air, detecting the green house gas methane and other organic pollutants

[1] Wolf and Silberberg, Nature Photonics 10, 77-79 (2016)
[2] Neves et al, APL Photonics 9, 096108 (2024)