Effect of crystal dichroism on the capability of wave-plates

In order to use the wave-plate better within the band with crystal dichroism,the effect of the dichroism on the circular polarized light induced by a λ/4 wave-plate, the plane of polarization rotated by a λ/2 wave-plate and the output amplitude was analyzed respectively based on matrix optics.Because of dichroic absorption of the crystal, the transmitted ray becomes elliptical polarized light instead of circular polarized light when the optical vector of the linear polarized light inputs at 45° with respect to the fast axis of the λ/4 wave-plate.For a λ/4 wave-plate,only when tan θ=exp(-△ad), the transmitted ray is circular polarized light with lower amplitude.As to a λ/2 wave-plate,with dichroism taken into account,the rotation angle of the optical vector of the linear polarized light is not twice as the angle between the optical vector of the incident light and the fast axis of the wave-plate.The rotation angle and amplitude are the function of the dichroic absorption coefficient and the angle between the vector of the incident light and the optical axis of the crystal.The results show that the crystal dichroism of the wave-plate cannot be ignored,it should be paid more attention.