Self-mixing-based photoacoustic sensor

Year: 2026

Authors: Gabbrielli T., Pelini J., Zhang CH., Cappelli F., de Cumis MS., Dello Russo S., Canino MC., Roncaglia A., De Natale P., Borri S.

Autors Affiliation: CNR, INO Ist Nazl Ott, Via N Carrara 1, I-50019 Sesto Fiorentino, Italy; LENS European Lab Nonlinear Spect, Via Carrara 1, I-50019 Sesto Fiorentino, Italy; ASI Agenzia Spaziale Italiana, Ctr Geodesia Spaziale, I-75100 Matera, Italy; Natl Res Council Italy, Inst Study Nanostruct Mat, CNR, ISMN, Via P Gobetti 101, I-40129 Bologna, Italy.

Abstract: In the vast panorama of optical-based detection strategies, photoacoustic spectroscopy is particularly suitable for its versatility, high sensitivity, and scalability potential. In cantilever-enhanced photoacoustic sensors, the interferometric readout of the membrane oscillation guarantees exceptional signal-to-noise ratio, often at the expense of limited compactness. In this work, we propose a novel approach combining cantilever-enhanced photoacoustic trace-gas excitation with self-mixing interferometry for absorption signal readout. The sensor performance has been compared in terms of detection sensitivity and stability over time to that achieved with a more complex state-of-the-art readout system using a bulky balanced Michelson interferometer. Both sensors, operated with the same excitation laser emitting at 4.57 mu m and addressing the same target N2O line, demonstrated the same spectroscopic results in terms of signal-to-noise ratio of the acquired spectra and the same minimum detection limit of 90 parts-per-billion at tens of seconds integration time. The self-mixing readout benefits from a much reduced size, paving the way for future system downsizing and easier integration while maintaining high-sensitivity detection levels. Moreover, the intrinsic wavelength independence of photoacoustic spectroscopy, together with the broad-spectral adaptability of self-mixing readout, allows, in principle, a wide wavelength-tailorability of the sensor.

Journal/Review: SENSORS AND ACTUATORS REPORTS

Volume: 12      Pages from: 100487-1  to: 100487-9

More Information: The authors acknowledge financial support from the European Union with the Next Generation EU with the Italian National Recovery and Resilience Plan (NRRP), Mission 4, Component 2, Investment 1.3, CUP D43C22003080001, partnership on Telecommunications of the Future (PE00000001-program RESTART) and the I-PHOQS Infrastructure Integrated infrastructure initiative in Photonic and Quantum Sciences [IR0000016, ID D2B8D520], with the Laserlab-Europe Project [G.A. n.871124], with the MUQUABIS Project Multiscale quantum bio-imaging and spectros copy [G.A. n.101070546], with the ForeSight Project (GA n.101168521), with the QUID project Quantum Italy Deployment [G.A. No 101091408]; from the Italian ES-FRI Roadmap (Extreme Light Infrastructure-ELI Project); from ASI and CNR under the Joint Project Laboratori congiunti ASI-CNR nel settore delle Quantum Technologies (QASINO) (Accordo Attuativo n. 2023-47-HH.0); from the Italian Ministero dell’Universita e della Ricerca (project PRIN-2022KH2KMT QUAQK). The project QOSTRAD Quantum-enhanced optomechanical sensors for trace gas detection (ID 59182/2024) funded by the European Union-Next Generation EU (PNRR-MUR) PE0000023-NQSTI (National Quantum Science and Technology Institute).
KeyWords: Photoacoustic sensing; Trace gas sensing; Quantum cascade laser; Infrared; Feedback interferometry; Optomechanics; Self mixing
DOI: 10.1016/j.snr.2026.100487