Design of the Wave Plate for Polychromatic Light

Sometimes the beams with different wavelengths are needed to alternatively applied to the polarized light path.In order to keep the light path in optimal state,the wave plates with corresponding wavelengths must be chosen according to the different operating wavelengths.For this reason an idea of multi-wavelength wave plate is put forward in the paper and the design method for the multi-wavelength wave plate is given.A double-wavelength quarter-wave plate with practical value is concretely designed and it has been successfully applied to a practical optical system,thus demonstrates the correctness of the design idea for multi-wavelength wave plate.The multi-wavelength wave plate is not fully equivalent to several wave plates in the strict significance,but the wave plate designed within a certain error range can fulfil the practical requirements,thus avoid the trouble for frequently changing the wave plates with different wavelengths.