These double crystal quartz wedges are so oriented as to cause a "depolarization" of polarized light, which is to say that if our Depolarizer is situated between a Polarizer and a rotating Analyzer, the resulting light transmitted through the Analyzer will not vary in intensity.

One type of depolarizer, the Lyot, does not have a “fast” or preferred axis. However, it is not entirely achromatic, and has wavelength periodicity in its depolarized spectrum. Another type is the wedge depolarizer. It is achromatic, but has a preferred axis, meaning that this axis must be oriented at 45° with respect to the plane of polarization, thus making it unusable in applications wherein the plane of polarization varies in attitude.

The OFR Depolarizer is a proprietary design. It is achromatic throughout its operating spectrum with no wavelength periodicity. Further, it does not possess a fast or preferred axis, so that it is effective in varying polarization applications. Being optically contacted, these can be used in the UV. Performance is optimized with expanded beams, >6 mm diameter. Power rating is ~10W/cm2. The DPU-15 is mounted in our standard retarder cell (see photo). The DPU-25 is not mounted. Antireflection coatings are optional.