Witoptics Photonics Inc.

A waveplate or retarder is an optical device that alters the polarization state of a light wave traveling through it.
A waveplate works by shifting the phase of the light wave between two perpendicular polarization components. A typical waveplate is simply a birefringent crystal with a carefully chosen thickness. The crystal is cut so that the extraordinary axis is parallel to the surfaces of the plate. When the extraordinary index is smaller than the ordinary index, as in calcite, the extraordinary axis is called the fast axis and the ordinary axis is called the slow axis. Light polarized along the fast axis propagates faster than light polarized along the slow axis. Thus, depending on the thickness of the crystal, light with polarization components along both axes will emerge in a different polarization state.

Half waveplate A half waveplate rotates linearly polarized light to any desired orientation. The rotation angle is twice the angle between the incident polarized light and optical axis.

Quarter Waveplate

When linearly polarized light is input at 45 deg to the axis of a quarter waveplate , the output is circularly polarized. Similarly, input circularly polarized light is transformed into linearly polarized light.
The thickness of the quarter waveplate is such that the phase difference is 1/4 wavelength (λ /4, Zero order) or certain multiple of 1/4-wavelength [(2n+1)λ /4, multiple order]

Witoptics provides standard waveplate wavelength(nm) listed as below:
 

Note for waveplate:
(1).Other wavelengths within the range of 250nm-1650nm are also available upon request.
(2).Holder: To use the roating holder is available upon request.