2.Polarizer - produces light in a special state of polarization at the output

3. Compensator - used to shift the phase of one component of the incident light
Depending on orientation, it transforms the ellipse of polarization
Linearly polarized light into elliptically polarized light when set to 45° in respect to the linear polarization axis.

4. Analyzer – second polarizer that detects the linearly polarized light reflected off the sample

5. Detector