Specular Reflectance is a technique for analyzing
transparent films which usually yield weak spectra by
ordinary transmission techniques. Applications include
surface coatings on reflecting substrates; film thickness
measurements by interference fringes and reflectivity
coefficient determinations of metals.
The application is the determining factor when deciding which angle of
incidence should be selected. A 30° angle of incidence is normally chosen for more routine samples which have coating thicknesses in the micrometer range. For very thin coatings in the nanometer thickness range, an 80° angle of incidence would be appropriate.
When sample thickness is unknown, the full range of specular reflectance
analysis can be performed conveniently with the VeeMAX III Variable Angle 30 - 85° accessory. Simply move the
sliding lever on the graduated scale to the desired angle.
Each accessory provides a reference mirror to permit the
operator to acquire a background spectrum. Their designs
eliminate stray light and ensure minimum energy loss.
Sensitivity can be further enhanced with the use of either a manual rotating wire grid polarizer or a automated wire grid polarizer.