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COLLIMATED LIGHT BEAM EXPANDER - COMPRESSOR

IP.com Disclosure Number: IPCOM000024705D
Original Publication Date: 1981-Oct-31
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 86K

Publishing Venue

Xerox Disclosure Journal

Abstract

Present laser diodes radiate energy in cones with elliptical symmetry. When the radiant energy is collimated, the surfaces of equal intensity are cylindrical ellipses. It is often desirable to convert the symmetry of the beam from elliptical to circular prior to collimation. This can be done with a device such as shown in the drawing.

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XEROX DISCLOSURE JOURNAL

COLLIMATED LIGHT BEAM EXPANDER
E. E. Price

Proposed - COMPRESSOR Classification

U.S. CI. 350/286

Int. C1. G02b 5/04

4

FIG. lo

FIG. lb

FfG. /c

Volume 6 Number 5 September/October 1981 253

[This page contains 1 picture or other non-text object]

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COLLIMATED LIGHT BEAM EXPANDER - COMPRESSOR (Cont'd)

Present laser diodes radiate energy in cones with elliptical symmetry. When the radiant energy is collimated, the surfaces of equal intensity are cylindrical ellipses. It is often desirable to convert the symmetry of the beam from elliptical to circular prior to collimation. This can be done with a device such as shown in the drawing.

Figure la shows a combination of two prisms 2 and 4. The prism faces, at which the light is normal, are in contact and rotated about the direction of beam propagation until they are positioned as shown. Figure lb is a side view of the prism combination showing the expansion of the light beam at the entering face. Figure lc is a top view of the prism combination showing the compression of the beam on emerging from prism 4.

Referring again to Figure la, the entering beam is shown as elliptical in cross section, with the minor axis vertical. The effect of the light beam passing through the entering face is to expand the minor axis as shown. Upon emerging from the face of prism 4, the major axis of the beam cross section is compressed as shown. Thus, by expanding the minor axis and compressing the major axis a...