Prismatic Phase Shifter

The prismatic phase shifter is a novel device that can be used to control the phase of a coherent beam of light. Phase shifting is becoming an integral function of most modern interferometric systems. Phase shifting can be accomplished by use of any of a variety of older devices including moving mirrors, rotating quarter-wave plates, moving gratings, and Bragg cells, all of which have disadvantages. Surface losses and/or changes in polarization are induced by these various devices. In the case of a moving mirror, subwavelength translation can be difficult. Some of the other older devices produce lateral shifts of the beam.