Our MProbe system measurement principle is based on spectroscopic reflectance and/or transmittance. Practically, any transluscent material coating or film can be measured.
MProbe systems are available in a wide wavelength range – from UV to IR; we select transparency window within this range. This means that even if material is totally opaque in the visible range (appears opaque to the eye), we still maybe able to measure it by using NIR or IR range. One example is thin film solar applications: absorbers (CIGS, CdTe, etc.) are specifically designed to absorb visible spectrum. Using the NIR wavelength range (900-1700nm) we are able to measure thickness of the absorbers without any problem. Surface roughness can also limit the ability to measure. Again, surface roughness effect increases dramatically at the shorter wavelength (UV and Vis) range – using NIR helps reduce its effect and makes measurement possible. Typically, films with surface roughness < 30nm can be measured using Visible system and with roughness <70nm with NIR system: in both case, actual roughness value can be determined as well.