Open-Path Detection of Organic Vapors via Quantum Infrared Spectroscopy

TL;DR

This paper demonstrates the first open-path detection of organic vapors using quantum Fourier transform infrared spectroscopy, showing its potential for practical, in-field gas detection through a novel interferometer setup and spectral analysis.

Contribution

It introduces the first application of a QFTIR spectrometer for ambient air organic gas detection, advancing practical in-field spectroscopy technology.

Findings

Successful detection of acetone, methanol, and ethanol vapors in ambient air.

Built a nonlinear Michelson interferometer with 1.7m arms for increased absorption.

Measured concentration changes of gases over time in real-world conditions.

Abstract

In recent years, quantum Fourier transform infrared (QFTIR) spectroscopy emerged as an alternative to conventional spectroscopy in the mid-infrared region of the spectrum. By harnessing induced coherence and spectral entanglement, QFTIR offers promising potential for the practical detection of organic gasses. However, little research was conducted to bring QFTIR spectrometers closer to domestic or in-field usage. In this work, we present the first use of a QFTIR spectrometer for open-path detection of multiple interfering organic gases in ambient air. The accurate identification of mixtures of acetone, methanol, and ethanol vapors is demonstrated with a QFTIR spectrometer. We achieved this breakthrough by building a nonlinear Michelson interferometer with 1.7m-long arms to increase the absorption length, coupled with analysis techniques from differential absorption spectroscopy. The evolution of different gasses' concentrations in ambient air was measured through time. These results constitute the first use-case of a QFTIR spectrometer as a detector of organic gasses, and thus represent an important milestone towards the development of such detectors in practical situations.