Results 171 to 180 of about 2,335 (228)

Scanning Optomechanical Enhanced BF-QEPAS for Ultrafast Gas Sensing

IEEE Sensors Journal
Traditional beat-frequency quartz-enhanced photoacoustic spectroscopy (BF-QEPAS) is constrained by short energy accumulation time and the necessity of attenuation cycles, resulting in weaker signals and longer measurement cycles. In this work, we propose
Yang Chen, Linzhao Jiang, Cheng Yu, Peng Zhang, Lei Wang, Dawei Wu   +5 more
openaire   +2 more sources

Calibration-free mid-infrared exhaled breath sensor based on BF-QEPAS for real-time ammonia measurements at ppb level

Sensors and Actuators B: Chemical, 2022
Breath analysis, compared with blood analysis, can enable real-time non-invasive diagnostics through quanti- fication of exhaled biomarkers. Here, we demonstrate, for the first time, a calibration-free mid-infrared (MIR) exhaled breath sensor for real ...
Biao Li, C. Feng, Hongpeng Wu, S. Jia, Lei Dong   +4 more
semanticscholar   +1 more source

Photoacoustic gas detection with LED QEPAS

2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
Various configurations and applications have been investigated and realized since the pioneering introduction of quartz-enhanced photoacoustic spectroscopy (QEPAS) by Kosterev et al. in 2002 [1]. However, the required submillimeter diameter of the acoustic resonator demands an excellent beam quality of laser source and precise adjustments of the QEPAS ...
Stefan Bottger, Martin Angelmahr, Wolfgang Schade   +2 more
openaire   +1 more source

QEPAS detector for rapid spectral measurements

Applied Physics B, 2010
A quartz enhanced photoacoustic spectroscopy sensor designed for fast response was used in combina- tion with a pulsed external cavity quantum cascade laser to rapidly acquire gas absorption data over the 1196- 1281 cm −1 spectral range. The system was used to measure concentrations of water vapor, pentafluoroethane (freon- 125), acetone, and ethanol ...
A. A. Kosterev, P. R. Buerki, L. Dong, M. Reed, T. Day, F. K. Tittel   +5 more
openaire   +1 more source

GaSb Diode Lasers for QEPAS Sensor Applications

Conference on Lasers and Electro-Optics, 2018
Newly developed tunable single mode laser diodes based on GaSb material system in the wavelength range 1.6 μm ≤ λ ≤ 4 μm are combined with the QEPAS technique for trace gas detection.
Tobias Milde, Morten Hoppe, Hervé Tatenguem, Wolfgang Schade, Joachim Sacher   +4 more
openaire   +1 more source

H2S near-IR QEPAS detection in complex gas matrices

Quantum Sensing and Nano Electronics and Photonics XIX, 2023
Hydrogen sulfide (H2S) is a harmful gas whose emissions are associated to natural gas leaks. Laser-based spectroscopy techniques have been demonstrated to be well suited for real time gas monitoring, providing high sensitivity and selectivity.
Mariagrazia Olivieri, Giansergio Menduni, Andrea Zifarelli, Marilena Giglio, Pietro Patimisco, Angelo Sampaolo, Vincenzo Spagnolo   +6 more
openaire   +2 more sources

The intra‐cavity QEPAS sensor using fiber‐ring laser for C2H2 and CO2 detection

Microwave and optical technology letters (Print), 2023
An intra‐cavity quartz‐enhanced photoacoustic spectroscopy (QEPAS) sensor using fiber‐ring laser is demonstrated. The sensor includes an erbium‐doped fiber (EDF) intra‐cavity laser and a quartz tuning fork (QTF), and realizes wavelength scanning through ...
Heng Zhang, Yuanfang Yu, Shaoqiang Bi, Qinduan Zhang, C. Tian, Zongliang Wang   +5 more
semanticscholar   +1 more source

QEPAS methane sensor performance for humidified gases

Applied Physics B, 2008
A trace gas sensor based on quartz enhanced photoacoustic spectroscopy (QEPAS) was evaluated using humidified nitrogen samples and ambient air. Relaxation processes following vibrational excitation of 2ν3 state of CH4 were investigated. Sensor performance at different gas pressures could be predicted based on a developed kinetic model.
A.A. Kosterev, Y.A. Bakhirkin, F.K. Tittel, S. McWhorter, B. Ashcraft   +4 more
openaire   +1 more source

Improved IP-QEPAS sensor based on cylindrical cavity enhancement

Infrared Physics & Technology, 2021
Abstract In this paper, a cylindrical cavity based in-plane quartz-enhanced photoacoustic spectroscopy (IP-QEPAS) was demonstrated for the first time. The cylindrical cavity was designed by theoretical mode and used as a resonator to improve the strength of acoustics wave.
Yinghao Hong, Shunda Qiao, Yufei Ma
openaire   +1 more source

Mid-infrared fiber-coupled QCL-QEPAS sensor

Applied Physics B, 2013
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SPAGNOLO, Vincenzo Luigi, Patimisco P., Borri S., Scamarcio G., Bernacki B. E., Kriesel J.   +5 more
openaire   +2 more sources