Abstract: A microscope for use in transmissive and reflective infrared spectral analysis of a sample positioned on a sample plane. The microscope uses a collimated beam for infinity correction. A collimated irradiating beam of infrared energy is input to the microscope and focused through a single confocal aperture whereupon the beam is re-collimated and provided to a focusing lens. The focusing lens focuses the beam on a subject sample which generates a resulting image beam. The resulting image beam is re-collimated and provided to an optical element which focuses the resulting image beam back through the single confocal aperture and to an infrared detector. In a preferred embodiment, the size of the single confocal aperture is adjustable and a dichroic element is included for providing simultaneous viewing and infrared measurement of a measured sample. Also in a preferred embodiment, a detector mounting apparatus is included for facilitating orientation of a detector at an infrared output of the microscope.

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.