Auto-Design of Multi-Pass Cell With Small Size and Long Optical Path Length Using Parallel Multi-Population Genetic Algorithm

In tunable diode laser absorption spectroscopy (TDLAS), the multipass cell (MPC) that comprises two identical and coaxial spherical mirrors can provide long optical path length (OPL) and reduce the limit of system detection. We proposed an intelligent method to design MPC with long optical path length (OPL) and small size using parallel multi-population genetic algorithm (PMPGA). The developed MPCs presented the maximum mirror utilization in the same size of spherical mirrors with the diameter of 25.4 mm and 40 mm. The performance of the developed MPCs were compared with other teams. We verified the results of PMPGA and obtained a micro MPC design with an OPL of 6.3 m. The diameter of the mirror was 25.4 mm, and the distance between the two mirrors was only 30.5 mm. And the developed MPC was verified by using TDLAS, which can improve the development of portable gas sensors.