A fresnel rhomb type phase retarder insensitive to the incident angle

This paper presents a fresnel rhomb-type phase retarders that is much highly insensitive to the incident angle.It is based on the properly choosed optical material and internal reflection angle.It shows that the device is stable within 0.3° of 90° fori ±2.5°,which is nearly one sixth of the ordinary fresnel rhomb phase retarders variation.