Zhang Qinduan, Chang Jun, Wang Qiang, Wang Zongliang, Wang Fupeng, Qin Zengguang
School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan 250100, China.
Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong, China.
Sensors (Basel). 2017 Dec 25;18(1):42. doi: 10.3390/s18010042.
We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency ₀ = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C₂H₂) to select the laser wavelength. The system achieved a linear response (R² = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.
我们提出了一种基于声光调Q光纤激光器的光声光谱气体检测新方法，即将一个透射式光声池（共振频率₀ = 5.3 kHz）合并到光纤激光腔内。通过声光调制器实现调Q，在占空比优化为10%的声光调制信号情况下，峰值脉冲功率达到约679 mW。我们使用了中心波长为1530.37 nm（C₂H₂的吸收峰）的定制光纤布拉格光栅来选择激光波长。该系统在400至7000 ppmv的浓度范围内实现了线性响应（R² = 0.9941），与传统强度调制系统相比，最低检测限提高了94.2倍。
