Polarizers

Given this assumption, there is a Bell inequality between the coincidence rates with polarizers and coincidence rates without polarizers.

As noted above and seen in the accompanying photograph, the chromaticity of birefringence typically creates colored patterns when viewed in between two polarizers.

In a typical device, a liquid crystal layer (typically 4 μm thick) sits between two polarizers that are crossed (oriented at 90° to one another).

Since the phase shift, and thus the change in polarization state, is usually wavelength dependent, such objects viewed under white light in between two polarizers may give rise to colorful effects, as seen in the accompanying photograph.

The following table gives examples of Jones matrices for polarizers: Phase retarders Phase retarders introduce a phase shift between the vertical and horizontal component of the field and thus change the polarization of the beam.

The polarizers can be considered as introducing which-path information to each beam.

The system requires only stable continuous spectral light source, two polarizers, an achromatic quarter-wave plate and a spectrometer.