Unlike standard waveplates, Achromatic Waveplates (Retarders) provide a constant phase shift independent of the wavelength of light that is used. This wavelength independence is achieved by using two different birefringent crystalline materials. The relative shifts in retardation over the wavelength range are balanced between the two materials used. The flat response of an Achromatic Waveplate (Retarder) is ideal for use with tunable lasers, multiple laser line systems, and other broad spectrum sources.
Designed to be used at an angle of incidence of 0°, changes of ±3° will yield less than 1% change in retardance. The 11.5mm clear aperture waveplates feature an air spaced construction; the 23mm clear aperture waveplates are cemented. All Achromatic Waveplates (Retarders) are mounted in an anodized aluminum housing with the fast axis clearly indicated.