The High Precision Achromatic Phase Retarder Design And Performance Testing Research

Phase retarders are important optical components that introduce a phase shift between orthogonal and linearly polarized components of light transmitted through them. Fitted with other polarimetric elements, they can realize modifying of light and controlling of polarization states. Achromatic retarder is such a device that can be used in wide spectrum in optical phase retardation. It is difficult to reach the high precision because of the width of spectrum. Modern polarization technology and optical modulation demand high precision not only for single wavelength but also for compounded wave-plate and "achromatic retarder. It has been solved for the former, but it has some gap for the latter in precision. So we design the new achromatic retarder with small retardation error as possible. It, is the common character that the direction of the input and the output rays are perpendicular to the surface of the rhomb, which are made of isotropy materials. The incident angle and emergence angle are fixed value, so the achromatic properties are not perfect. Fresnel rhomb; Mooney rhomb and the improved design of AD—1. AD—2 are good examples. In this paper, we present a simple introduction of achromatic retarders, which include two , types: compounded-birefringence type and total internal reflection type. The paper represent the analysis to the principle of the phase retardation and the parameters which induced the change of phase retardation .It also give the design of achromatic phase retarder and the achromatic property curve within the range of 365nm to 1150nm theoretically, which shows the retardation error is smaller than 0.4 degree, which is nearly one-fifth of the ordinary Fresnel rhomb phase retardation. Based on the principle of polarizing modulation, this paper set up an experiment system for measuring the phase retardation for high precision achromatic retarder, whose shape is rhomb. The results indicate that the principle of high precision achromatic retarder is correct and the measurement error is less than 0.5%, it reaches the high precision and can be satisfied the demand of application.