Circular Polarization
How can we make circularly polarized light??
- Birefringence!
- Birefringent materials (crystals or stressed plastics) have the property that the speed of light is different in the two transverse dimensions.
- Since the frequency of the wave must remain constant as the wave passes through the birefringent material, the wavelength must be different in the two dimensions, which allows for a phase change.
The relative phase change (fast vs slow) is determined by the thickness