INTERNAL REFLECTION ELEMENT FOR EXAMINING TRACE AMOUNTS OF MATERIAL USING INFRARED SPECTROSCOPY

摘要

Mid-infrared transparent elements (1) with different geometries to examine sample surfaces (7) by Internal Reflectance Micro Infrared Spectroscopy. An infrared beam (I) from an IR microscope, collimated or focused, enters the element (1) and impinges on an inclined surface (2) of contact between the sample (7) and the element (1) at an angle above the critical angle. The IR beam is internally reflected at the inclined surface (2), travels inside the element (1), reaches a reflector surface (5) where the beam is reflected back to retrace its path. The beam once again comes in contact with the sample (7) at the inclined surface (2) and is reflected. The retracing is accomplished by: a) a mirrored outer surface where the internally reflected beam strikes the element (1), b) a retro mirror assembly placed outside the surface where the internally reflected beam strikes the element (1). The center of curvature of this mirror coincides with the point of contact between the sample (7) and the inclined surface (2).