Accession Number : AD0697731

Title :   REFRACTIVE INDICES OF INFRARED-TRANSMITTING SUBSTRATE MATERIALS CALCULATED USING STANDARD SPECTROPHOTOMETER TRANSMITTANCE CURVES.

Descriptive Note : Special publication, Jun 68-May 69,

Corporate Author : EDGEWOOD ARSENAL MD

Personal Author(s) : Carlon,Hugh R.

Report Date : NOV 1969

Pagination or Media Count : 16

Abstract : A method is described for quickly determining refractive indices of infrared-transmitting substrates and window materials. Using two or more known sample thicknesses, spectrophotometer transmittance curves are run on standard laboratory equipment. Equations are developed which permit direct computation of the index from these data. The technique is applicable to other wavelength regions and can be extended to be used in the determination of indices of liquids. Calculations can be continued through regions of anomaly; i.e., through strong spectral absorption bands if desired. The method is mathematically rigorous, and accuracy of computed results will usually depend only upon spectrophotometer transmittance reading and sample thickness measurement accuracies. The third decimal place is attainable when suitable samples are available. A dispersion curve for polyethylene is presented. (Author)

Descriptors :   (*INFRARED FILTERS, INFRARED OPTICAL MATERIALS), (*INFRARED OPTICAL MATERIALS, REFRACTIVE INDEX), SUBSTRATES, WAVE PROPAGATION, INFRARED WINDOWS, POLYETHYLENE PLASTICS, OPTICAL GLASS, INFRARED SPECTROPHOTOMETERS, INFRARED SPECTROSCOPY, THICKNESS, SCATTERING, GRAPHICS, EQUATIONS, ACCURACY

Subject Categories : Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE