可调谐半导体激光吸收光谱(TDLAS)是近年发展起来的一种激光光谱气体检测技术，相比于常见的电化学、离子导电陶瓷等技术，其具有选择性强、灵敏度高、响应快、可在线测量、抗背景光谱干扰能力强等优点，适用于复杂环境中气体的长期在线检测。氧气(O₂)是人类生存环境中的重要气体，O₂浓度的检测在生产生活各个领域应用广泛、意义重大。基于此，本文采用TDLAS技术对空气中的O₂进行高灵敏度测量。采用输出波长为760 nm的半导体激光器作为光源，直接吸收光谱法获得环境中的氧气浓度为20.56%，最小检测极限为5.53×10⁻³。在波长调制方法中，优化了激光波长调制深度，得到了完整的二次谐波波形，可用于标定氧气浓度。此系统的信噪比为380.74，最小检测极限约为540×10⁻⁶。本文的传感系统具有良好的O₂检测能力，可广泛用于各个领域中的O₂浓度检测。

The characteristics of stimulated Brillouin scattering (SBS) in perfluorinated amine media and the experimental structure used in hundreds of picoseconds pulse compression at 532 nm are demonstrated. A two-stage SBS pulse compression structure is adopted for this work. The compact double-cell SBS compression structure and the scattering media FC-70 are chosen to compress the incident light from 9.5 to about 1 ns in the first stage. Then, the light is used as the pumping source for the second pulse compression. In the second stage, using a single-cell SBS structure in a pulse compression system, perfluorinated amine media with different phonon lifetimes, such as FC-3283, FC-40, FC-43, and FC-70, are chosen to run the comparative experimental study. The narrowest compressed pulse times obtained are 294, 274, 277, and 194 ps; they respectively correspond to the above listed media. The average width of the compressed pulse width is 320 ps for FC-3283, with a fluctuation range of 87 ps. For FC-40, the average pulse width is 320 ps, with a fluctuation range of 72 ps. And for FC-43, the average pulse width is 335 ps, with a fluctuation range of 88 ps. However, the average pulse width is only 280 ps for FC-70, with a fluctuation range of 57 ps. The highest energy reflectivity is more than 80% for all of the media. The experimental results show that a two-stage SBS pulse compression system has lower pump energy requirements, thus making it easier to achieve a compressed pulse waveform. The results also show that the shorter the phonon lifetime of the medium, the narrower the obtained compressed pulse width.