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Exposed-In-Place Holographic Laser Collimator/Circularizer Lens

IP.com Disclosure Number: IPCOM000037440D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Levenson, MD: AUTHOR

Abstract

The diverging elliptical beam produced by a semiconductor diode laser is converted to a collimated circular beam by a holographic optical element on the output window of the laser package. Since the characteristics of the laser and its position relative to the output window varies, the holographic optical element is exposed and processed in place on each laser.

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Exposed-In-Place Holographic Laser Collimator/Circularizer Lens

The diverging elliptical beam produced by a semiconductor diode laser is converted to a collimated circular beam by a holographic optical element on the output window of the laser package. Since the characteristics of the laser and its position relative to the output window varies, the holographic optical element is exposed and processed in place on each laser.

Holographic media photosensitive to the diode laser wavelength is coated on the output window. The laser package itself may have an additional window through which a reference beam with the desired spatial characteristics can also be relayed to the output window. The laser frequency is stabilized using the Hollberg resonant feedback technique (Dahmani, Hollberg, Drullinger; Optics Letters 12, 654 (1987)). The reference beam is also derived by spatial filtering from the output of the uncollimated laser diode. Exposure of the holographic medium records the interference pattern between the reference wave and the uncollimated diode laser output. Development of the hologram then causes the diode output beam to be diffracted into a replica of the reference beam. The result is that every laser will produce an identical output beam, independent of the exact characteristics and structure of the laser itself. The personalized hologram corrects for any variation.

Phase conjugation techniques also can be used to provide the reference wave when no extra wi...