Design of Dual-wavelength High Precision Achromatic Phase Retarder

In order to meet the demand of precise measurement and applications, based on the total-reflection phase transformation theory of the phase retardation, the principle of phase retardation with oblique incident angle is expounded. Spectral characterization of the phase retardation varing with refractive index is analyzed to high precision achromatic phase retarder to oblique incidence aided design. The result indicates that there is a maximum to dispersion curve of achromatic phase retarder with oblique incident in the center of the design refractive index department. The phase-delay drops on both sides to the center of the refractive index and can pass through a definite retardance value twice at two specified wavelength values. Accordingly, based on the detailed design of Fresnel rhomb, The new achromatic retarder with the specific incident angle and high precision is designed by choosing suitable meterial It is shown at the achromatic property curve within the range of 500 urn to 1150 nm theoretically that the maximum deviation of the retardance from 90 degrees is 0.006 degrees, whereas at lambda R1R=532 urn and lambda R2R-1064 nm the retardance is approximately 90 degrees +/- 0.001 degrees. and the corresponding calculation to the size of the devices indicates that the size of the devices for the same aperture will decrease for higher refractive index values. So optical materials with higher refractive indices are more convenient for this type of oblique incidence retarder.