Patent ID: 9194794
Filing Date: 2015-11-24
Classification: G01N

Abstract:
1. An optical absorption spectroscopy apparatus comprising a multi-pass optical cell comprising a first reflector and a second reflector, a first light source for light of a first waveband and a second light source for light of a second waveband that is different from the first waveband, the cell being constructed and arranged such that light entering the cell is reflected one or more times between the first and second reflectors before exiting the cell, and wherein light of the first waveband comprises a first input beam that enters the cell and a first output beam that exits the cell, wherein the first input beam and the first output beam lie in a first plane, and light of the second waveband comprises a second input beam that enters the cell and a second output beam that exits the cell, wherein the second input beam and the second output beam lie in a second plane that is different from the first plane, and wherein a line normal to the first plane and a line normal to the second plane lie in a common plane that coincides with a main optical axis of the multi-pass cell.