光学多通池被广泛应用于吸收光谱气体检测中，用来增加吸收光程，提高探测灵敏度。提出了一种由两块圆型柱面镜构成的光学多通池，其结构紧凑，镜面有效利用率高，相比传统相同基长的多通池可实现的光程有很大的增加。通过调节前后两柱面镜的间距和相对旋转角度，可得到不同的光斑分布，实现不同的光程。实验中使用1.653 μm 的分布反馈式二极管激光器作为光源，采用直接吸收光谱方法对CH4气体进行了探测，在气体有效吸收光程为13.8 m 的情况下，检测极限达到了0.68 μmol/mol，并利用该系统实现了大气中的CH4探测。

The optical multipass cell has been widely used in the detection of absorption spectroscopy to increase the optical path length and improve the detection sensitivity. A multipass optical cell based on two cylindrical mirrors is described for application to tunable diode laser absorption spectroscopy. The multipass cell has the characteristics of simple and compact structure, high efficient use of mirror area, longer optical path length at the same base length compared with traditional multipass cells. Rotation of the cylindrical mirrors and variation in the cell base length have been used to achieve different spot patterns and path lengths. CH4 direct absorption measurement using the multipass cell with a fibre- coupled distributed- feedback laser at 1.653 μm has been performed. Detection sensitivity of 0.68 μmol/mol is realized for absorption optical path length of 13.8 m, and the detection of atmospheric CH4 has been achieved with the system.