Abstract: Monochromatic exciting light is transmitted in a forward direction from a source through a sample to a spherical mirror. The spherical mirror reflects the light in a backward direction through the sample and images the light upon a flat mirror. The flat mirror reflects the light in the forward direction, through the sample, to the spherical mirror, thereby causing the light to be reflected in the backward direction, through the sample, to the source. The reflections increase the optical path length of the light through the sample, thereby enhancing a fluorescent emission therefrom.

Abstract: A first monochromator includes a diffraction grating that is adapted for occlusion by a mirror. When the mirror occludes the grating, a white light input is transmitted through the first monochromator and through a sample under test, thereby causing a transmission of non-absorbed light from the sample. When the grating is unoccluded, monochromatic light is transmitted from the first monochromator so that a selected bandwidth of fluorescence excitation energy is incident on the sample. Fluorescence emission from the sample is diffracted by a second monochromator which provides diffracted light which is recorded by a vidicon.

Abstract: A dual beam differential spectrophotometer using a rotating chopper wheel having reflective transparent, and opaque sectors transmits light alternately through standard and sample material cells for comparison. Diffuse reflectors insertable in the material cells permit the apparatus to be used either as a differential spectrofluorometer or as a differential absorption meter.