Circularizing Prism With Right Angle Beam Paths
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
The output from commercial laser diodes is commonly elliptical in cross-section. In many applications circularization of the beam is desirable, and this is generally performed by passing the beam through a prism or prism pair. In optical storage devices a circular beam is desired so that a good combination of small spot size and high efficiency may be obtained when the beam is passed through an objective lens and focused onto the media. In these storage devices the data and servo signals are returned by laser light reflected from the media. This returning beam travels back through the objective lens and along the same path as the outbound beam. A beam splitter, usually consisting of a beam-splitting cube separator from the circularizing optics, is used to separate the outbound and return paths.