Patent ID: 7378913
Filing Date: 2008-05-27
Classification: G04F

Abstract:
1. An improved frequency standard of the type wherein a beam of circularly-polarized light passes through an alkali vapor resonance cell, the improved frequency standard being characterized in that: the beam of circularly-polarized light is produced by passing a beam of linearly-polarized light through a circular polarizer, the circular polarizer being rotatable around an axis that is parallel to the beam of light, the circular polarizer includes a linear polarizer and a quarter wave retarder, whereby the intensity of the circularly-polarized beam is controlled by rotating the circular polarizer wherein during rotation, an axis of polarization of the linear polarizer and a fast axis of the quarter wave retarder have a fixed orientation to each other, wherein the linear polarizer and the quarter wave retarder are rotated as a unit.