Millimeter and submillimeter wavelength spectroscopy of natural minerals and metals

Optical constants of natural minerals are of interest for characterizing interstellar dust, for remote sensing of terrain and for light scattering in the atmosphere by soil particles. The authors have measured the optical constants of a number of naturally occurring minerals which do not occur as single crystals using the pressed pellet technique (without binder). The advantages and disadvantages of this method will be discussed. In the far infrared, metals are expected to be Drude-like. Measurements are presented to illustrate how well this expectation holds. Two different methods of making these measurements will be discussed.