System Parameters Selection and Optimization of Tunable Diode Laser Absorption Spectroscopy
GAO Nan1, DU Zhen-hui1*, TANG Miao2, YANG Jie-wen1, YANG Chun-mei1, WANG Yan1
1. College of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China 2. Tianjin Environmental Monitoring Center, Tianjin 300191, China
Abstract：The system performance of tunable diode laser absorption spectroscopy (TDLAS) is affected by the modulation parameters such as modulation index, modulation frequency, scanning amplitude and scanning frequency. There is a lack of definite parameters selection basis in practical measurement. Aiming at this problem, the influence of modulation parameters on second harmonic signals was observed by experiment based on a certain theory in the present paper, and the basis and method of modulation parameters optimization for various system functions and demands were summarized by analyzing the signal characteristic including amplitude, signal to noise ratio, symmetry and peak width. For the system of concentration or temperature detection the amplitude and signal to noise ratio will be taken into prior consideration which require optimum modulation index, lower modulation frequency and lower scanning frequency. In condition of pressure detection deduced by lineshape the signal symmetry and peak width are more important to ascertain the modulation parameters according to practical demands. Scanning amplitude will be adjusted to obtain complete signal waveforms, then scanning frequency can be adjusted according to system speed and accuracy requirement. The result of the experiment provided a definite basis for conforming the working state of such system.
高 楠1，杜振辉1*，唐 邈2，杨杰文1，杨春梅1，汪 曣1. 可调谐二极管激光吸收光谱技术参数选择及优化[J]. 光谱学与光谱分析, 2010, 30(12): 3174-3178.
GAO Nan1, DU Zhen-hui1*, TANG Miao2, YANG Jie-wen1, YANG Chun-mei1, WANG Yan1. System Parameters Selection and Optimization of Tunable Diode Laser Absorption Spectroscopy . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2010, 30(12): 3174-3178.
