Abstract: An optical measuring cell designed and provided for the absorption spectroscopic determination of at least one chemical and/or physical parameter of a fluid. A light beam for the absorption spectroscopic analysis is coupled into an interior of a housing, together with the fluid to be analyzed, via a coupling-in element connected to the housing such that the coupled-in light beam runs in the interior of the housing in parallel to the optical main axis of the measuring cell or the housing. A coupling-out element connected to the housing couples a light beam striking the coupling-out element out of the housing in order to supply the light beam, after multiple passes through the interior, to a detector for the absorption spectroscopic determination of a chemical and/or physical parameter of the irradiated fluid.

Abstract: A gas cell (1) for the spectroscopic, in particular absorption spectroscopic, analysis of a gas, in which the gas is exposed to an incident beam of rays (S) of electromagnetic radiation and a beam of rays (SA) of electromagnetic radiation exiting the gas is detected to form a measurement signal, wherein the gas cell (1) comprises a body (10) formed by a porous, electromagnetic radiation-scattering material, an in-coupling device (20) for coupling the incident beam of rays (S) into the gas cell (1) and an out-coupling device (30) for coupling the exiting beam of rays (SA) out of the gas cell (1), wherein, according to the invention, the gas cell is further developed according to the invention by forming a material-free cavity (12) in the body (10), which is surrounded by an inner surface (14) running within the material and is both diffusely reflecting and transmitting the electromagnetic radiation.