Method and apparatus for shaping electromagnetic beams

摘要

The intensity profile of a beam of electromagnetic waves such as a laser beam is shaped by means of a diffraction grating and/or prism in the beam path. In one embodiment, beams exhibiting Gaussian energy intensity profiles undergo an energy redistribution to approximately uniform profiles. A reflective or transmissive surface relief grating is employed with phase steps generally periodic except at the pattern center where a pattern phase reversal occurs. Prisms are cut and oriented relative to the incoming beam to operate at the Brewster's angle for compressing or expanding the beam with minimum losses.