© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

arXiv:2405.12822 · APL Photonics

Open-path detection of organic vapors via quantum infrared spectroscopy

Simon Neves, Adimulya Kartiyasa, Shayantani Ghosh, Geoffrey Gaulier, Luca La Volpe, Jean‐Pierre Wolf

Published Sep 1, 2024• 11 citations

Abstract

In recent years, quantum Fourier transform infrared (QFTIR) spectroscopy has emerged as an alternative to conventional absorption spectroscopy in the mid-infrared region of the spectrum. 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. 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. We 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. We thus characterize our spectrometer’s sensitivity to acetone, methanol, and ethanol vapors and demonstrate the accurate identification of mixtures of these gases released in ambient air. We show this characteristic is preserved over time by performing a measurement overnight and tracking the evolution of different gases’ average concentrations. These results constitute the first use-case of a QFTIR spectrometer as a detector of organic gases and, thus, represent an important milestone toward the development of such detectors in practical situations.

DOI: 10.1063/5.0220707

Related papers

Detection of Organic Gases in Air via Quantum Fourier-Transform Mid-Infrared Spectroscopy

Simon Neves, Adimulya Kartiyasa, Shayantani Ghosh +3 more

A Quantum FTIR spectrometer was used to detect, discriminate and track organic gases in ambient air with unprecedented sensitivity, leveraging spectral entanglement, induced coherence, long-path absorption, and specific analysis techniques such as DOAS.

Quantum 2.0 Conference and Exhibition•Jan 1, 2024•0 citations

High resolution Fourier-transform mid-infrared spectroscopy using nonlinear interferometers

Jachin Kunz, Chiara Lindner, Simon J. Herr +3 more

Nonlinear interferometers based on correlated photon pairs allow mid-infrared spectroscopy by measuring only near-infrared photons with a silicon-based detector, which offers higher detectivities than mid-infrared detectors. Here, we use the nonlinear interferometer not only to determine the transmission of a sample but also for spectral analysis - analogue to classical Fourier transform infrared (FTIR) spectrometers. The Quantum FTIR analyzes the absorption of gas mixtures with high spectral resolution over a broad mid-infrared wavelength range. Improved emission rates of the photon pair source yield sensitivities similar to a classical FTIR despite an extremely low light exposure on the sample.

Optical and Quantum Sensing and Precision Metrology II•Mar 8, 2023•1 citation

Remote Infrared Absorption Spectroscopy with Undetected Photons

Simon Neves, Fériel Armbruster, Jean-Pierre Wolf

We demonstrate a novel method for remote open-path Fourier-transform infrared spectroscopy with undetected photons. Similar to previous quantum spectroscopy works, a mid-infrared spectrum is reconstructed by detecting a near-infrared radiation only, thus bypassing important limitations of infrared detectors. Our study however relies on the co-propagation of the photon-pair and the pump-laser over the same optical path, which allows the probing of the open atmosphere over long distances. By sending the photons over unprecedented distances of up-to 43.4m in the outdoor atmosphere, we were able to detect butane released in the open-path, as well as natural atmospheric methane, thus demonstrating the first use of infrared spectroscopy with undetected photons for atmospheric measurements.

quant-pharXiv:2607.16419•Jul 21, 2026•0 citations

Quantum Fourier-Transform Infrared Spectroscopy for Complex Transmittance Measurements

Yu Mukai, Masaya Arahata, Toshiyuki Tashima +2 more

Harnessing the quantum interference of the pair generation processes, infrared quantum spectroscopy, based on nonlinear interferometers with visible-infrared photon-pair sources, enables the extraction of the infrared optical properties of a sample through visible photon detection without the need for an infrared optical source or detector. We develop a theoretical framework for quantum Fourier-transform infrared (QFTIR) spectroscopy. The proposed Fourier analysis method, which fully utilizes the phase information in the interferogram, allows us to determine the complex transmittance and optical constants for a sample in a simple setup without the use of any dispersive optics for spectral selection. In the experimental demonstrations, the transmittance spectrum of a bandpass filter and the refractive index of silica glass are measured in the near-infrared region using QFTIR operated in a low gain regime; these results agree well with the independently measured spectrum using a conventional spectrometer and an value estimated from references. These demonstrations prove the validity and great potential of QFTIR spectroscopy.

Physical Review Applied•Mar 8, 2021•48 citations

Quantum Fourier-transform infrared spectroscopy in the fingerprint region

Yu Mukai, Ryo Okamoto, Shigeki Takeuchi

Infrared quantum absorption spectroscopy is one of the quantum sensing techniques, by which the infrared optical properties of a sample can be estimated through visible or near infrared photon detection without need for infrared optical source or detector, which has been an obstacle for higher sensitivity and spectrometer miniaturization. However, experimental demonstrations have been limited to wavelengths shorter than 5 µm or in the terahertz region, and have not been realized in the so-called fingerprint region of 1500–500 cm−1 (6.6 to 20 µm), which is commonly used to identify chemical compounds or molecules. Here we report the experimental demonstration of quantum Fourier-transform infrared (QFTIR) spectroscopy in the fingerprint region, by which both absorption and phase spectra (complex spectra) can be obtained from Fourier transformed quantum interferograms obtained with a single pixel visible-light detector. As demonstrations, we obtained the transmittance spectrum of a silicon wafer at around 10 µm (1000 cm−1) and complex transmittance spectrum of a synthetic fluoropolymer sheet, polytetrafluoroethylene, in the wavelength range of 8 to 10.5 µm (1250 to 950 cm−1), where absorption due to stretching modes of C-F bonds is clearly observed. These results open the way for new forms of spectroscopic devices based on quantum technologies.

arXiv:2110.14247•Optics Express•May 24, 2022•69 citations

Quantum Fourier-transform infrared spectroscopy in the far-infrared region

Yu Mukai, Ryo Okamoto, Shigeki Takeuchi

Quantum Fourier-transform (QFTIR) spectroscopy enables the estimation of infrared optical properties only by detecting visible or near-infrared light, harnessing the quantum interference between the successive photon-pair generation processes. We demonstrate QFTIR spectroscopy in the finger print region around 10 µm.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)•Jan 1, 2022•0 citations

In recent years, quantum Fourier transform infrared (QFTIR) spectroscopy has emerged as an alternative to conventional absorption spectroscopy in the mid-infrared region of the spectrum. 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. 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. We 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. We thus characterize our spectrometer’s sensitivity to acetone, methanol, and ethanol vapors and demonstrate the accurate identification of mixtures of these gases released in ambient air. We show this characteristic is preserved over time by performing a measurement overnight and tracking the evolution of different gases’ average concentrations. These results constitute the first use-case of a QFTIR spectrometer as a detector of organic gases and, thus, represent an important milestone toward the development of such detectors in practical situations.

Nonlinear interferometers based on correlated photon pairs allow mid-infrared spectroscopy by measuring only near-infrared photons with a silicon-based detector, which offers higher detectivities than mid-infrared detectors. Here, we use the nonlinear interferometer not only to determine the transmission of a sample but also for spectral analysis - analogue to classical Fourier transform infrared (FTIR) spectrometers. The Quantum FTIR analyzes the absorption of gas mixtures with high spectral resolution over a broad mid-infrared wavelength range. Improved emission rates of the photon pair source yield sensitivities similar to a classical FTIR despite an extremely low light exposure on the sample.

We demonstrate a novel method for remote open-path Fourier-transform infrared spectroscopy with undetected photons. Similar to previous quantum spectroscopy works, a mid-infrared spectrum is reconstructed by detecting a near-infrared radiation only, thus bypassing important limitations of infrared detectors. Our study however relies on the co-propagation of the photon-pair and the pump-laser over the same optical path, which allows the probing of the open atmosphere over long distances. By sending the photons over unprecedented distances of up-to 43.4m in the outdoor atmosphere, we were able to detect butane released in the open-path, as well as natural atmospheric methane, thus demonstrating the first use of infrared spectroscopy with undetected photons for atmospheric measurements.

Harnessing the quantum interference of the pair generation processes, infrared quantum spectroscopy, based on nonlinear interferometers with visible-infrared photon-pair sources, enables the extraction of the infrared optical properties of a sample through visible photon detection without the need for an infrared optical source or detector. We develop a theoretical framework for quantum Fourier-transform infrared (QFTIR) spectroscopy. The proposed Fourier analysis method, which fully utilizes the phase information in the interferogram, allows us to determine the complex transmittance and optical constants for a sample in a simple setup without the use of any dispersive optics for spectral selection. In the experimental demonstrations, the transmittance spectrum of a bandpass filter and the refractive index of silica glass are measured in the near-infrared region using QFTIR operated in a low gain regime; these results agree well with the independently measured spectrum using a conventional spectrometer and an value estimated from references. These demonstrations prove the validity and great potential of QFTIR spectroscopy.

Infrared quantum absorption spectroscopy is one of the quantum sensing techniques, by which the infrared optical properties of a sample can be estimated through visible or near infrared photon detection without need for infrared optical source or detector, which has been an obstacle for higher sensitivity and spectrometer miniaturization. However, experimental demonstrations have been limited to wavelengths shorter than 5 µm or in the terahertz region, and have not been realized in the so-called fingerprint region of 1500–500 cm−1 (6.6 to 20 µm), which is commonly used to identify chemical compounds or molecules. Here we report the experimental demonstration of quantum Fourier-transform infrared (QFTIR) spectroscopy in the fingerprint region, by which both absorption and phase spectra (complex spectra) can be obtained from Fourier transformed quantum interferograms obtained with a single pixel visible-light detector. As demonstrations, we obtained the transmittance spectrum of a silicon wafer at around 10 µm (1000 cm−1) and complex transmittance spectrum of a synthetic fluoropolymer sheet, polytetrafluoroethylene, in the wavelength range of 8 to 10.5 µm (1250 to 950 cm−1), where absorption due to stretching modes of C-F bonds is clearly observed. These results open the way for new forms of spectroscopic devices based on quantum technologies.