Patent ID: 8508740

Claim:
An optical multi-pass cell ( 100 ), comprising: a housing ( 101 ) defining a sample cavity ( 109 ) for receiving a sample under test; first and second end mirrors ( 103 , 104 ) positioned within the housing ( 101 ), separated by a distance, L, and facing one another coaxially to an optical axis ( 113 ) extending between the first and second end mirrors ( 103 , 104 ), the first and second mirrors ( 103 , 104 ) being configured to reflect a beam of light directed at one of the first or second end mirrors ( 103 , 104 ) off-axis from the optical axis ( 113 ) one or more times between the first and second end minors ( 103 , 104 ) through the sample cavity ( 109 ) at a first distance from the optical axis ( 113 ) to create a first beam pattern ( 330 ); and one or more relay mirrors ( 220 ) positioned to intercept the beam of light and configured to reflect the beam of light such that at least a second beam pattern ( 331 ) is created between the first and second end mirrors ( 103 , 104 ) at a distance from the optical axis ( 113 ) different from the first distance of the first beam pattern ( 330 ) such that the second beam pattern ( 331 ) does not overlap the first beam pattern ( 330 ).