The present invention relates to a multi-pass
cell cavity structure capable of quickly performing double-point calibration with a single-concentration
calibration gas, which includes a
laser, a first cavity mirror with an incident port, a second cavity mirror, a reflector, and a
detector. The
laser, the reflector, and the
detector are located outside the first cavity mirror. The first cavity mirror and the second cavity mirror are arranged opposite to each other, and a double-sided cavity mirror is provided between the first cavity mirror and the second cavity mirror. The emitted light of the
laser enters the
optical cavity between the first cavity mirror and the second cavity mirror from the incident port according to the incident angle designed by the multi-pass
cell, and travels back and forth multiple times in the
optical cavity and then exits from the incident port. The emitted light that exits is directed into the
detector through the reflector, and the detector is used to measure the change in
laser light intensity. This multi-pass
cell cavity structure is ingenious. By adding the double-sided cavity mirror, double-point calibration can be achieved based on a single-concentration
calibration gas, which can reduce the number of calibration times, improve the calibration rate, and subsequently save the
calibration gas used, reduce the usage cost, and enhance the
usage experience.