Patent ID: 8592768
Filing Date: 2013-11-26
Classification: G01N

Abstract:
1. A fiber optic evanescent absorption sensor, comprising: a first light source, said first light source provides a signal in a wavelength region of a weak absorption band; a second light source, said second light source provides a signal in a wavelength region of a strong absorption band; a mirror with an aperture; a sample; an evanescent wave fiber within said sample having no cladding in a region of interaction with said sample; a first lens; a second lens; a detection system; whereby light from said first light source originates as a wide beam and is converted into an annular beam by said mirror with said aperture; whereby light from said second light source is a narrow beam and is passed through said mirror with said aperture and is focused together with said light from said first light source by said first lens and directed into said evanescent wave fiber; whereby said light from said first and second light sources experiences absorption within said evanescent wave fiber in said region of interaction with said sample; and whereby an output from said evanescent fiber is focused by said second lens into said detection system, said detection system adapted to analyze absorption characteristics of said sample.