Cui Ruyue, Yuan Yupeng, Qui Sicheng, Han Wenfei, Huang Jing, Wang Lu, Wu Hongpeng, Chen Weidong, Dong Lei
State Key Laboratory of Quantum Optics Technologies and Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China.
Anal Chem. 2025 Jul 1;97(25):13095-13102. doi: 10.1021/acs.analchem.5c00484. Epub 2025 Jun 13.
Monitoring carbon dioxide (CO) concentrations is crucial for environmental protection and various industrial applications. This study presents a high-sensitivity photoacoustic spectroscopy (PAS) sensing system based on an innovative 3D-printed multipass (MP) Helmholtz cell designed to enhance CO detection efficiency. The MP-Helmholtz photoacoustic cell, fabricated using high-precision 3D printing technology, achieves a high level of integration among a compact multipass cell, the acoustic wave detection chamber containing a microphone, and the capillary resonance components. The multipass cell, consisting of two identical spherical mirrors, generates 160 laser beams within an effective volume of 20 mL, thereby extending the effective absorption path length and accumulating excitation light power. Consequently, results indicate that the signal amplitude of this 3D-printed MP Helmholtz cell is increased by a factor of 21, compared to that of traditional Helmholtz photoacoustic cells. Utilizing a near-infrared distributed feedback laser (DFB) tuned to the CO absorption line at 6361.25 cm, the sensing system achieved a minimum detectable limit (MDL) of 4.5 ppmv. The corresponding NNEA was 3.0 × 10 cm·W·Hz. An optimal detection limit of 330 ppbv was established with a 48-s averaging time, demonstrating robust sensitivity. Continuous monitoring CO in ambient air validated the system's stability. In comparison to alternative methods for enhancing the photoacoustic effect, such as the use of Herriott cells or erbium-doped optical fiber amplifiers, the Helmholtz cell equipped with a specially designed optical multipass cell offers a highly effective and cost-efficient approach for improving resonant photoacoustic signals.
监测二氧化碳（CO）浓度对于环境保护和各种工业应用至关重要。本研究提出了一种基于创新的3D打印多程（MP）亥姆霍兹池的高灵敏度光声光谱（PAS）传感系统，旨在提高CO检测效率。采用高精度3D打印技术制造的MP-亥姆霍兹光声池，在紧凑的多程池、包含麦克风的声波检测室和毛细管共振组件之间实现了高度集成。由两个相同球面镜组成的多程池在20 mL有效体积内产生160束激光束，从而延长了有效吸收路径长度并积累了激发光功率。结果表明，与传统亥姆霍兹光声池相比，这种3D打印的MP亥姆霍兹池的信号幅度提高了21倍。利用调谐到6361.25 cm处CO吸收线的近红外分布反馈激光器（DFB），该传感系统实现了4.5 ppmv的最低检测限（MDL）。相应的噪声等效吸收系数为3.0×10 cm·W·Hz。在48秒的平均时间下建立了330 ppbv的最佳检测限，显示出强大的灵敏度。对环境空气中的CO进行连续监测验证了该系统的稳定性。与增强光声效应的其他方法（如使用赫里奥特池或掺铒光纤放大器）相比，配备特殊设计光学多程池的亥姆霍兹池为改善共振光声信号提供了一种高效且经济高效的方法。
