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Diode Pumped Laser With Increased Efficiency

IP.com Disclosure Number: IPCOM000077236D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Farmer, GI: AUTHOR [+3]

Abstract

Electroluminescent (EL) diode-pumped Nd:YAG lasers have progressed during the past few years from cryogenically cooled devices to the present room temperature operation. These advances have occurred largely because of improved optical coupling techniques between the diode sources and the laser rod. At the present time, the most efficient systems utilize an elliptical reflective cavity in which the diodes and the laser rod are placed at the two foci of the ellipse. These systems are costly, because the elliptical reflector is very expensive to fabricate and means must be provided to support the rod and the diodes within the cavity.

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Diode Pumped Laser With Increased Efficiency

Electroluminescent (EL) diode-pumped Nd:YAG lasers have progressed during the past few years from cryogenically cooled devices to the present room temperature operation. These advances have occurred largely because of improved optical coupling techniques between the diode sources and the laser rod. At the present time, the most efficient systems utilize an elliptical reflective cavity in which the diodes and the laser rod are placed at the two foci of the ellipse. These systems are costly, because the elliptical reflector is very expensive to fabricate and means must be provided to support the rod and the diodes within the cavity.

This system overcomes these disadvantages and also improves the diode emission efficiency by more than four hundred percent over the present systems. As shown in the figure, the laser rod 2 and the diode array 3 are disposed at the foci of a transparent solid elliptical cylinder 4, having a reflective coating 5 formed on the outer surface of the cylinder.

Cylinder 4 may be fabricated from a transparent material such as undoped YAC or plexiglass. Coating 5 may be either gold or silver. The diodes may be fabricated from CaAlAs and the rod may be Nd:YAG. An undoped YAG cylinder is an excellent index matching material between the diode and laser rod. This reduces Fresnel's reflection and increases the total internal reflection angle, thereby substantially increasing the diode efficiency. Moreover...