Shang Zhijin, Li Shangzhi, Li Biao, Wu Hongpeng, Sampaolo Angelo, Patimisco Pietro, Spagnolo Vincenzo, Dong Lei
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, PR China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, PR China.
Photoacoustics. 2022 May 4;26:100363. doi: 10.1016/j.pacs.2022.100363. eCollection 2022 Jun.
A sensor system for exhaled ammonia (NH) monitoring exploiting quartz-enhanced photoacoustic spectroscopy (QEPAS) was demonstrated. An erbium-doped fiber amplifier (EDFA) with an operating frequency band targeting an NH absorption line falling at 1531.68 nm and capable to emit up to 3 W of optical power was employed. A custom T-shaped grooved QTF with prong spacing of 1 mm was designed and realized to allow a proper focusing of the high-power optical beam exiting the EDFA between the prongs. The performance of the realized sensor system was optimized in terms of spectrophone parameters, laser power and modulation current, resulting in a NH minimum detectable concentration of 14 ppb at 1 s averaging time, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 8.15 × 10 cm W/√Hz. Continuous measurements of the NH level exhaled by 3 healthy volunteers was carried out to demonstrate the potentiality of the developed sensor for breath analysis applications.
展示了一种利用石英增强光声光谱（QEPAS）监测呼出氨气（NH₃）的传感器系统。采用了一种掺铒光纤放大器（EDFA），其工作频带针对位于1531.68 nm处的NH₃吸收线，能够发射高达3 W的光功率。设计并实现了一种定制的T形带槽石英音叉（QTF），其叉指间距为1 mm，以便将离开EDFA的高功率光束在叉指之间进行适当聚焦。根据分光光度计参数、激光功率和调制电流对所实现的传感器系统性能进行了优化，在1 s平均时间下，NH₃的最小可检测浓度为14 ppb，对应归一化噪声等效吸收系数（NNEA）为8.15×10⁻⁹ cm W/√Hz。对3名健康志愿者呼出的NH₃水平进行了连续测量，以证明所开发的传感器在呼吸分析应用中的潜力。
