A Wavelength Standard for the Near Infrared Based on the Reflectance Of Rare-Earth Oxides

This work describes the techniques used to prepare and analyze a reflectance wavelength standard composed of three rare-earth oxides. A mixture of dysprosium oxide (DY20.1), erbium oxide (Er203). and holmium oxide (Ho20) provides a pressed powder specimen exhibiting a near infrared reflectance spectrum characterized by many discrete absorption minima in the wavelength range 700 to 2000 urn. The object of this activity was to develop a wavelength standard for improving the accuracy of reflectance measurements in the near infrared. The reflectance minima of the rare-earth oxide mixture was analyzed for the effects of varying spectral resolution and temperature. The uncer-