A multipass cell for absorption measurements with laser light is described. The number of passes is adjusted by variation of the distance of two parallel concave mirrors. The position and direction of the exit beam do not change when the path length is varied. A cell of 1-m length was used for infrared absorption measurements with an effective path length between 3 and 150 m.
© 1981 Optical Society of America
J. Altmann, R. Baumgart, and C. Weitkamp, "Two-mirror multipass absorption cell," Appl. Opt. 20, 995-999 (1981)