Accession Number : AD0908426

Title :   Calibration of Instruments Measuring Reflectance and Transmittance.

Descriptive Note : Technical publication,

Corporate Author : NAVAL WEAPONS CENTER CHINA LAKE CA

Personal Author(s) : Bennett, Jean M. ; Ashley, E. J.

Report Date : FEB 1973

Pagination or Media Count : 17

Abstract : In calibrating instruments that measure reflectance and transmittance to a few tenths of a percent, it is desirable to have a sample that is smooth, uniform, nonabsorbing, and stable, so that the measured reflectance and transmittance will add to unity, and no light will be either absorbed or scattered outside the collecting optics. A properly prepared, thin, transparent, high index film (such as CeO2 or TiO2) on a fused quartz substrate is suitable for a calibration sample. Equations are given to calculate the reflectance and transmittance both at normal incidence and nonnormal incidence, as well as to correct for multiple reflections in the substrate and reflection from the back surface of the substrate. Factors such as aging and optical thickness nonuniformity, which can introduce systematic errors into the calibration, must be minimized by proper choice of materials and preparation techniques. (Author)

Descriptors :   (*REFLECTOMETERS, CALIBRATION), (*SPECTROPHOTOMETERS, CALIBRATION), OPTICAL MATERIALS, REFLECTIVITY, LIGHT TRANSMISSION, MEASUREMENT, QUARTZ, FILMS, CESIUM COMPOUNDS, OXIDES, TITANIUM COMPOUNDS.

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE