Description
Fresnel Rhomb Retarders, like Achromatic Waveplate, can provide a uniform retardation over a wide range of wavelengths. Since the retardation of Fresnel Rhomb Retarders only depends on the refractive index and geometry of the material, the wavelength range is wider than Achromatic Waveplate made from birefringent crystal. A Single Fresnel Rhomb Retarders produces a phase retardation of λ/4, the output light is parallel to the input light, but laterally displaced; A Double Fresnel Rhomb Retarders produces a phase retardation of λ/2, it consists of two Single Fresnel Rhomb Retarders. Union Optic provides standard BK7 Fresnel Rhomb Retarders, other material like ZnSe and CaF2 is available upon request.
