Simple technique for the fabrication of a penta prism with high accuracy right angle deviation

摘要

What we believe to be a new technique for the fabrication of a penta prism (PP) with high accuracy rightangle deviation of the incident beam is presented. We derive simple formulas relating to the error in right angle deviation (E) with the errors in 45 deg (beta) and 90 deg (delta) angles of a PP, and we determine E from the angle (E_(r)) between the plane wavefronts reflected from the right angled surfaces (external Fresnel reflection on the entrance surface and internal Fresnel reflection on the exit surface) of a PP and the angular error (delta) between the same surfaces. The error in right angle deviation E is determined from the measurement of E_(r) using an autocollimator and a Fizeau interferometer, and E is corrected to a high order of accuracy during the final stage of polishing one of the slanted surfaces of the PP. A new technique to determine the magnitude and direction of the small values of E_(r) is proposed and verified. The result for a PP is presented.