Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2309.08218 · Advanced Quantum Technologies

Broadband Spectroscopy and Interferometry with Undetected Photons at Strong Parametric Amplification

Kazuki Hashimoto, D. B. Horoshko, Maria V. Chekhova

Published Dec 24, 2023• 16 citations
arXivHTMLPDF

Abstract

Abstract Nonlinear interferometry with entangled photons allows for characterizing a sample without detecting the photons interacting with it. This method enables highly sensitive optical sensing in the wavelength regions where efficient detectors are still under development. Recently, nonlinear interferometry has been applied to interferometric measurement techniques with broadband light sources, such as Fourier‐transform infrared spectroscopy and infrared optical coherence tomography. However, they have been demonstrated with photon pairs produced through spontaneous parametric down‐conversion (SPDC) at a low parametric gain, where the average number of photons per mode is much smaller than one. The regime of high‐gain SPDC offers several important advantages, such as the amplification of light after its interaction with the sample and a large number of photons per mode at the interferometer output. This work presents broadband spectroscopy and high‐resolution optical coherence tomography with undetected photons generated via high‐gain SPDC in an aperiodically poled lithium niobate crystal. To prove the principle, reflective Fourier‐transform near‐infrared spectroscopy with a spectral bandwidth of 17 THz and optical coherence tomography with an axial resolution of 11 µm are demonstrated.

DOI
10.1002/qute.202300299

Related papers

Broadband Sensing with Undetected Photons with Strong Parametric Amplification

Kazuki Hashimoto, Maria V. Chekhova

We develop an SU(1,1) interferometer with an aperiodically-poled LiNbO3 crystal in the high-parametric-gain regime to demonstrate Fourier-transform spectroscopy and optical coherence tomography with undetected photons.

•Jan 1, 2023•0 citations

Nonlinear interferometers for Fourier-transform infrared spectroscopy with visible light

Chiara Lindner, Jachin Kunz, Sebastian Wolf +2 more

Nonlinear interferometers based on non-degenerate spontaneous parametric down-conversion (SPDC) create a link between separate spectral ranges. This allows for measurements in remote spectral regions while detecting light in easily accessible wavelengths. In our work, we use periodically poled lithium niobate to create correlated signal (visible or near-infrared) and idler (mid-infrared) photon pairs. Using a nonlinear interferometer in Michelson geometry, we obtain broadband mid-infrared spectra from light detected with a silicon avalanche photodiode. Combining the nonlinear interferometer with a measurement scheme in close analogy to classical Fourier-transform infrared spectroscopy allows for sub-wavenumber spectral resolution, which opens up possibilities for applications such as precise spectroscopic gas analysis.

Nonlinear Frequency Generation and Conversion: Materials and Devices•Mar 4, 2021•0 citations

High-sensitivity quantum sensing with pump-enhanced spontaneous parametric down-conversion

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

Recent years have seen the development of quantum sensing concepts utilizing nonlinear interferometers based on correlated photon pairs generated by spontaneous parametric down-conversion (SPDC). Using SPDC far from frequency degeneracy allows a “division of labor” between the mid-infrared photon for the strongest sample interaction and the correlated near-infrared photon for low-noise detection. The small number of photons provided by SPDC and the resulting inferior signal-to-noise ratio are, however, a limiting factor preventing the wide applicability of the novel sensing concept. Here, we demonstrate a nonlinear interferometer based on pump-enhanced SPDC with strongly improved emission rates while maintaining broadband spontaneous emission. For validation of the concept, we demonstrate high-resolution mid-infrared spectroscopy with near-infrared detection, showcasing improved accuracy. Although the number of mid-infrared photons is about five orders of magnitude smaller than in classical spectrometers, the sensitivity of the quantum spectrometer becomes comparable, marking an essential step toward real-world applications.

arXiv:2208.07595•APL Photonics•May 1, 2023•22 citations

Fourier-transform infrared spectroscopy with undetected photons from high-gain spontaneous parametric down-conversion

Kazuki Hashimoto, D. B. Horoshko, Mikhail I. Kolobov +3 more

Abstract Fourier-transform infrared spectroscopy (FTIR) is an indispensable analytical method that allows label-free identification of substances via fundamental molecular vibrations. However, traditional FTIR spectrometers require mid-infrared (MIR) elements, including low-efficiency MIR photodetectors. SU(1,1) interferometry has previously enabled FTIR with undetected MIR photons via spontaneous parametric down-conversion in the low-parametric-gain regime, where the number of photons per mode is much less than one and sensitive photodetectors are needed. In this work, we develop a high-parametric-gain SU(1,1) interferometer for MIR-range FTIR with undetected photons. Using our method, we demonstrate three major advantages: a high photon number at the interferometer output, a considerably lower photon number at the sample, and improved interference contrast. In addition, we broaden the spectral range of the interferometer by aperiodic poling in the gain medium. Exploiting the broadband SU(1,1) interferometer, we measure and evaluate the MIR absorption spectra of polymers in the 3-μm region.

arXiv:2403.05423•Communications Physics•Jul 4, 2024•21 citations

Generation of broadband spontaneous parametric fluorescence and its application to quantum optical coherence tomography

Masayuki Okano, Ryo Okamoto, Akira Tanaka +4 more

Optical coherence tomography (OCT) based on Michelson interferometer has widely been utilized in biology and medicine as a type of optical biopsy and quantum optical coherence tomography (QOCT) based on Hong-Ou-Mandel interferometer has recently been demonstrated. By use of quantum entangled photon pairs generated via spontaneous parametric down conversion (SPDC) process, axial resolution of QOCT can be better than that of OCT in principle for a source of same bandwidth and group velocity dispersion (GVD) effect for QOCT can be automatically cancelled thanks to the frequency correlation of entangled photon pairs. To realize high-resolution QOCT, we need a broadband quantum entangled photon pair source. Then we proposed a novel conventional method to generate broadband spontaneous parametric fluorescence via SPDC by using multiple nonlinear crystals pumped by a CW laser. Our method has controllability to tune the center frequency of generated photons and scalability to extend the number of crystals. This conventional method can enable us to achieve sub-micron axial resolution of QOCT.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 1, 2011•0 citations

Quantum metrology with undetected mid-infrared photons for applied non-destructive testing

Paul Gattinger, Andreas W. Schell, Maja Buchegger +2 more

Metrology with undetected photons is an emerging technique that leverages quantum effects and photon correlations (entanglement) to retrieve valuable information in a target spectral range (e.g., mid-infrared, mid-IR) using measurements in an easily accessible domain (e.g., visible, near-IR). The underlying quantum process of spontaneous parametric down-conversion (SPDC) is utilized to generate non-degenerate correlated signal and idler photons to serve as detection and probing photons, respectively. Sensing with undetected photons enables important advantages, such as ultra-low probe powers, room-temperature operation, and shot-noise-limited detection. In this contribution, we apply a quantum nonlinear interferometer based on an SPDC source to perform applied mid-IR spectroscopy, mid-IR microscopy, and mid-IR optical coherence tomography (OCT) as among the most promising techniques for quantum-based routine non-destructive testing. Moreover, we characterize the system, benchmark it against classical systems, and provide a prospective outlook for this new technology.

quant-pharXiv:2607.12653•e+i Elektrotechnik und Informationstechnik•Jul 15, 2026•0 citations
Abstract Nonlinear interferometry with entangled photons allows for characterizing a sample without detecting the photons interacting with it. This method enables highly sensitive optical sensing in the wavelength regions where efficient detectors are still under development. Recently, nonlinear interferometry has been applied to interferometric measurement techniques with broadband light sources, such as Fourier‐transform infrared spectroscopy and infrared optical coherence tomography. However, they have been demonstrated with photon pairs produced through spontaneous parametric down‐conversion (SPDC) at a low parametric gain, where the average number of photons per mode is much smaller than one. The regime of high‐gain SPDC offers several important advantages, such as the amplification of light after its interaction with the sample and a large number of photons per mode at the interferometer output. This work presents broadband spectroscopy and high‐resolution optical coherence tomography with undetected photons generated via high‐gain SPDC in an aperiodically poled lithium niobate crystal. To prove the principle, reflective Fourier‐transform near‐infrared spectroscopy with a spectral bandwidth of 17 THz and optical coherence tomography with an axial resolution of 11 µm are demonstrated.
Nonlinear interferometers based on non-degenerate spontaneous parametric down-conversion (SPDC) create a link between separate spectral ranges. This allows for measurements in remote spectral regions while detecting light in easily accessible wavelengths. In our work, we use periodically poled lithium niobate to create correlated signal (visible or near-infrared) and idler (mid-infrared) photon pairs. Using a nonlinear interferometer in Michelson geometry, we obtain broadband mid-infrared spectra from light detected with a silicon avalanche photodiode. Combining the nonlinear interferometer with a measurement scheme in close analogy to classical Fourier-transform infrared spectroscopy allows for sub-wavenumber spectral resolution, which opens up possibilities for applications such as precise spectroscopic gas analysis.
Recent years have seen the development of quantum sensing concepts utilizing nonlinear interferometers based on correlated photon pairs generated by spontaneous parametric down-conversion (SPDC). Using SPDC far from frequency degeneracy allows a “division of labor” between the mid-infrared photon for the strongest sample interaction and the correlated near-infrared photon for low-noise detection. The small number of photons provided by SPDC and the resulting inferior signal-to-noise ratio are, however, a limiting factor preventing the wide applicability of the novel sensing concept. Here, we demonstrate a nonlinear interferometer based on pump-enhanced SPDC with strongly improved emission rates while maintaining broadband spontaneous emission. For validation of the concept, we demonstrate high-resolution mid-infrared spectroscopy with near-infrared detection, showcasing improved accuracy. Although the number of mid-infrared photons is about five orders of magnitude smaller than in classical spectrometers, the sensitivity of the quantum spectrometer becomes comparable, marking an essential step toward real-world applications.
Abstract Fourier-transform infrared spectroscopy (FTIR) is an indispensable analytical method that allows label-free identification of substances via fundamental molecular vibrations. However, traditional FTIR spectrometers require mid-infrared (MIR) elements, including low-efficiency MIR photodetectors. SU(1,1) interferometry has previously enabled FTIR with undetected MIR photons via spontaneous parametric down-conversion in the low-parametric-gain regime, where the number of photons per mode is much less than one and sensitive photodetectors are needed. In this work, we develop a high-parametric-gain SU(1,1) interferometer for MIR-range FTIR with undetected photons. Using our method, we demonstrate three major advantages: a high photon number at the interferometer output, a considerably lower photon number at the sample, and improved interference contrast. In addition, we broaden the spectral range of the interferometer by aperiodic poling in the gain medium. Exploiting the broadband SU(1,1) interferometer, we measure and evaluate the MIR absorption spectra of polymers in the 3-μm region.
Optical coherence tomography (OCT) based on Michelson interferometer has widely been utilized in biology and medicine as a type of optical biopsy and quantum optical coherence tomography (QOCT) based on Hong-Ou-Mandel interferometer has recently been demonstrated. By use of quantum entangled photon pairs generated via spontaneous parametric down conversion (SPDC) process, axial resolution of QOCT can be better than that of OCT in principle for a source of same bandwidth and group velocity dispersion (GVD) effect for QOCT can be automatically cancelled thanks to the frequency correlation of entangled photon pairs. To realize high-resolution QOCT, we need a broadband quantum entangled photon pair source. Then we proposed a novel conventional method to generate broadband spontaneous parametric fluorescence via SPDC by using multiple nonlinear crystals pumped by a CW laser. Our method has controllability to tune the center frequency of generated photons and scalability to extend the number of crystals. This conventional method can enable us to achieve sub-micron axial resolution of QOCT.
Metrology with undetected photons is an emerging technique that leverages quantum effects and photon correlations (entanglement) to retrieve valuable information in a target spectral range (e.g., mid-infrared, mid-IR) using measurements in an easily accessible domain (e.g., visible, near-IR). The underlying quantum process of spontaneous parametric down-conversion (SPDC) is utilized to generate non-degenerate correlated signal and idler photons to serve as detection and probing photons, respectively. Sensing with undetected photons enables important advantages, such as ultra-low probe powers, room-temperature operation, and shot-noise-limited detection. In this contribution, we apply a quantum nonlinear interferometer based on an SPDC source to perform applied mid-IR spectroscopy, mid-IR microscopy, and mid-IR optical coherence tomography (OCT) as among the most promising techniques for quantum-based routine non-destructive testing. Moreover, we characterize the system, benchmark it against classical systems, and provide a prospective outlook for this new technology.