Emission polarization study on quartz and calcite.
Spectral emission polarization of quartz and calcite polished plates for observation angles of 20 degrees and 70 degrees is calculated by the substitution of complex index of refraction values for each mineral into Fresnel's equations. The emission polarization is shown to be quite wavelength-dependent, demonstrating that selected narrow or medium-width (Deltalambda approximately 1.5 microm) spectral bands exhibit a significantly higher percentage of polarization than a broad spectral band (Deltalambda approximately 6microm) for these two minerals. Field measurements with a broadband infrared radiometer yield polarizations on the order of 2% for a coarse-grained granite rock and beach sand (both quartz-rich). This implies that a more sensitive detector with a selected mediumwidth filter may be capable of measuring emission polarization accurately enough to make this parameter useful as a remote sensing tool for discrimination among rocks on the basis of texture.
Vincent
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