OPTICAL MULTI-PASS DITCH Russian patent published in 2021 - IPC G01N21/03 B01J19/12 

FIELD: chemical engineering.

SUBSTANCE: optical multi-pass ditch contains a container into which a gas sample is fed and a pair of concave mirrors facing each other inside the container. The laser beam directed into the container is reflected multiple times by the concave mirrors. At least one convex lens is located in the optical path of a laser beam that is repeatedly reflected between a pair of concave mirrors such that the central axis of the lens is tilted relative to the central axis of the concave mirrors. An acute angle is formed between the central axis of the convex lens and the central axis of the concave mirrors, which is less than or equal to the critical angle.

EFFECT: invention provides a compact ditch that does not require cooling, and increased number of laser beam reflections.

1 cl, 9 dwg