Abstract: A four port scanning Michelson interferometer suppresses self-emission by using either a beamsplitter that is uncoated or a beamsplitter that has reflection enhancing dielectric coatings in the splitting and combining areas of the substrate on opposite sides of the substrate. Both beamsplitters are fabricated from infrared optical materials that have a predetermined absorptivity in a predetermined wavelength interval which is from 2 ?m (5000 cm?1) to 13 ?m (770 cm?1) in the infrared. The optical materials of the uncoated beamsplitter are selected from a group of materials made up of ZnSe, ZnS, CdS, CdTe, Silicon, Germanium or Diamond. The optical materials of the other beamsplitter are selected from a group of materials made up of KBr, KCl, NaCl, CsI, BaF, CaF and the like.

Abstract: A two-beam interferometer for Fourier Transform spectroscopy has a double pivot scanning mechanism. The interferometer has two rigid pendulums that are each rotatable to swing around an associated one of distinct axes of rotation. A linkage links the two rigid pendulums to each other and constrains their rotation relative to each other. The interferometer has bearings, which may be flexure bearings, for rotatably mounting the two pendulums to swing around an associated one of the distinct axes of rotation and a first and a second bearing linking the linkage to an associated one of the pendulums. The two rigid pendulums, the linkage and the bearings can be a monolithic structure.

Abstract: A conduit-mounted light-transmitting device (10) for allowing optical analysis of a substance through a process line conduit (14) made of a light-transmitting material. The device (10) comprises a clip (24) adapted to be detachably secured about the conduit section. The clip (24) defines an optical path intersecting the conduit section when the clip (24) is mounted thereon.