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Prism-Pair Anamorphic Beam Expanders with Fixed Beam Offset

IP.com Disclosure Number: IPCOM000116192D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Dewey, AG: AUTHOR

Abstract

Anamorphic beam expanders are often used with diode lasers to create a circular beam. Commercial devices use a pair of prisms which expand the beam in one axis and give a circular beam parallel to the input but offset from it (Fig. 1).

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Prism-Pair Anamorphic Beam Expanders with Fixed Beam Offset

      Anamorphic beam expanders are often used with diode lasers to
create a circular beam.  Commercial devices use a pair of prisms
which expand the beam in one axis and give a circular beam parallel
to the input but offset from it (Fig. 1).

      Changing the angles of the prisms changes the expansion ratio
M, and devices are available with M from 2 to 6 but with different
values of the offset D (Fig. 2).

      By changing the spacing C (Fig. 2) as the angles are changed,
it is possible to produce a range of beam expanders with a fixed
offset D.  Such devices would be more suitable for installation in a
product employing laser diodes which have a significant range of
divergence angles, and hence require a range of expanders to obtain
round beams.  Having a fixed offset simplifies the design of the
optical path in the product.