[Testing research of achromatic phase retarder's spectral character]

Using established testing system by principle of normalized polarizing modulation, we measured the spectral characters of normal Fresnel rhomb, improved Fresnel rhomb, oblique-incidence rhomb and rectangle prism compound rhomb phase retarders. Through the measured spectral we yield the characteristic achromatism curves of all kinds of achromatic phase retarders, and analyse the results. The results indicate that the achromatism of the improved Fresnel rhomb and rectangle prism compound rhomb phase retarders is superior to others. Currently the improved Fresnel rhomb and retangle prism compound rhomb phase retarders are the ideal and utility-type achromatic phase retarders.