text: * Photo-reflectance measures differential reflectivities as small as one part per million, whereas ellipsometry and/or standard reflectance measure differential reflectivities on the order of one part per thousand. 
  * Photo-reflectance spectra exhibits sharp derivative-like structures localized at interband transition energies, whereas ellipsometry and/or standard reflectance exhibit broad slowly varying spectra. 
  * The photo-reflectance response at a particular wavelength typically arises from specific interband transitions confined to specific materials within the sample. 
  * By using phase-locked detection methods, ambient (nonsynchronous) light does not influence photo-reflectance measurements.
  * By using a laser probe beam, the refractive part of the photo-reflectance response can be isolated without the necessity to take spectroscopic data or perform a fit procedure.
  * Laser photo-reflectance has been proven in statistical process control for microelectronics manufacturing for over three decades.