Long-path gas absorption cell optical system

A long-path gas absorption cell optical system, characterized in that it comprises a first reflector (1) and a second reflector (2), wherein the first reflector (1) and the second reflector (2) are set opposite and spaced apart;

• the second reflector (2) is equipped with a light input port (3) and a light output port (4), and the first reflector (1), the second reflector (2), the light input port (3), and the light output port (4) together constitute a reflective optical system;
• wherein a collimated light beam enters through the light input port (3), reflects between the first reflector (1) and the second reflector (2), and exits through the light output port (4);
• the second reflector (2) includes a concave surface and an outer annular surface, with the concave surface set within the outer annular surface;
• the light input port (3) and the light output port (4) are both located on the outer annular surface of the second reflector (2);
• the first reflector (1) is a concave mirror;
• and
• wherein a light path of the collimated light beam reflecting between the first reflector (1) and the second reflector (2) is as follows:
• the collimated light beam enters through the light input port (3) and first reaches the first reflector (1), reflects off the first reflector (1) to the concave surface of the second reflector (2), then reflects off the second reflector (2) back to the first reflector (1), and finally from the first reflector (1) to the outer annular surface of the second reflector (2);
• wherein a pattern of reflection of the light path of the collimated light beam repeats.