Wave plates are made from birefingent material. The velocities of the extraordinary and ordinary rays that go through the birefingent material vary inversely with the refractive indices. The difference in velocity produces a phase difference when the two beams recombine. In the case of an incident linearly polarized beam, the phase difference is equal to δ = 2πd(ne-no)/λ . Notice that for any wavelength, the phase difference is controlled by the thickness of the wave plate.
Sinoceramics provides many kinds of wave plates, such as Low-order wave plates, cemented zero-order wave plates, airspaced zero-order wave plates, true zero-order wave plates and dual wavelength wave plates. We also provide wave plates with different retardation as half-wave, quarter-wave, octadic-wave, and full-wave. If you want to order the specific retardation of wave plate for your system, Sinoceramics is able to design any type for the customer. High precision and mass production is available upon request. Sinoceramics also has a high precision wave plate-master, which can test wave plates with retardation tolerances < 1/600.