Laboratory Measurements of Multi-spectral, Polarization, and Angular Characteristics of Light Reflected from Particulate Samples

Abstract

AbstractVisible and near-infrared reflectance spectroscopy is a powerful technique in remotely identifying the mineralogical and chemical compositions of planetary surface materials. Reflectance spectra measured at varied illumination and viewing conditions may also reveal the physical properties of planetary surfaces. The accurate data interpretation would require quantitative modeling as well as laboratory measurements of analog samples, in particular the granular materials. Here we describe three light scattering facilities constructed at China University of Geosciences used in spectrophotometric measurements of particulate samples. The first one is a three-colour (633, 532, and 473 nm) goniometer capable of measuring the polarized bi-directional reflectance from phase angle 2 to 130 degrees in the principal plane. The second one is a multi-angular imaging device capable of measuring reflectance in the upper hemisphere at discrete wavelengths (typical values include 458, 633, 750, and 905 nm). The third one is a bi-directional reflectance spectrometer that covers the wavelength range from 350 to 2500 nm. For each instrument, we first introduce the instrument concept and system descriptions, followed by the calibration and characterizations. Typical measurement results with applications to planetary remote sensing are then presented.