Achromatic waveplate is made from two different substrate materials such as crystal quartz and magnesium fluoride. For the single material, waveplate’s working wavelength is very limited because of the dispersion of the material. Achromatic Waveplate uses two different kinds of materials with the different dispersion and such waveplate is not sensitive to the wavelength change.

Achromatic waveplate is similar to zero order waveplate except that the two plates are made from different birefringent crystals. Since the dispersion of the birefringence of two materials is different, it is possible to specify the retardation values at a broad wavelength range. In other words, it can be used at a broadband wavelength range.