Spectroscopic Reflectance and Transmittance

Reflectance and transmittance characterize the main optical properties of virtually all materials. Using reflectance, the ratio of light reflected from a sample and incident light can be determined. Transmittance method measures the ratio of transmitted and incident light. The methods can be applied e.g. for characterization of:

  • Optical layers, such as antireflective or highly reflective coatings, to determine the main purpose of the layer
  • Absorber materials in solar cells
  • Color impression of a material wherever esthetical aspects have to be considered (e.g. in architectural glass for building fronts). This can be done by analyzing the spectral distribution of transmitted and reflected light.

Furthermore, the spectrum of reflected and transmitted light bears information on deposited layers and layer stacks. Reflectance and transmittance occur not only on surfaces, but also at all interfaces in multilayer systems. This generates superpositions of electro-magnetic light waves and characteristic interference patterns in the spectrum.
LayTec has developed sophisticated optical models for obtaining information from measured reflectance and transmittance spectra about thickness, color and other properties of deposited layers. Our in-situ and in-line metrology tools perform fast and contactless monitoring of of deposited layers and layer stacks in various fields of application. The LayTec software analyses measured spectra immediately and facilitates direct data exchange for in-situ and in-line process control.