Abstract: A multiple internal reflectance crystal has a sample surface and a bottom surface and reflective beveled ends such that energy may enter normal to the bottom surface, reflect off one beveled end to the bottom surface, from the bottom surface to the top surface, down the length of the crystal, and exit the crystal normal to the bottom surface by reflecting off of another beveled end. The crystal may be optically linked with light pipes and positioned at a location remote from the source and receiver of energy.

Abstract: The optical system of the present invention comtemplates directing a beam of radiant energy to either an aperture beam splitter or polarizing beam splitter. Radiant energy from the beam splitter forms a first remote image at an entrance to an image scrambler so that any image information which the beam contains is destroyed. The output of the scrambler fills the full aperture of a focusing objective that reproduces the image of the output of the scrambler onto a sample. A mask, positioned at a remote image between the output of the scrambler and focusing objective, determines the geometrical shape of the sample image. The focusing objective images the radiant energy that is reflected from the sample to a second remote image at the scrambler so that the scrambler destroys image information while retaining spectroscopic information. The beam splitter reflects a portion of the radiant energy from the scrambler to the detector.

Abstract: Diffuse reflectance spectra may be obtained that are free from the distortions caused by specular reflections by using an apparatus and method for physically blocking out specularly reflected energy. The apparatus consists of a blocker that is positioned substantially in contact with the surface of the sample at the region wherein an input beam of energy is focused on the sample. Specularly reflected energy that would otherwise be reflected to a detector is physically blocked by the blocker. That part of the input energy beam that penetrates into the sample is diffusely reflected. Part of the diffusely reflected energy passes under the blocker where it is collected and focused on the detector. The blocker is found to have particular application in the field of infrared spectroscopy of inorganic compounds, particularly compounds having a powdered structure.

Abstract: A reflecting beam splitting objective employing only three mirrors obtains a high reflective efficiency. In one embodiment, the objective contains a small intercepting mirror between primary and secondary mirrors of a Cassegrain mirror arrangement. The position of the intercepting mirror is determined so that the mirror receives an input beam and directs that beam onto a first portion of the secondary mirror without vignetting the beam when it is reflected from the secondary mirror to a first portion of the primary mirror or by cutting off part of the image transmitted from the second portion of the secondary mirror to a focus behind the primary mirror. The objective may use all energy that is input into the objective to image a sample. The objective has demonstrated particular utility in the field of infrared spectroscopy of small samples.