The United States of America As Represented by the United States

University of California

Howard T Powell

William F Krupke

Stephen Anthony Payne

Raymond John Beach

Eric C Honea

Charles Robert Wolfe

E Victor George

Camille Bibeau

Steven B Sutton

John H Campbell

John R Murray

James E Murray

Christopher D Marshall

James C Swingle

Charles K Rhodes

Richard E Lyon

Michael O Riley

Edward S Jessop

Kenneth S Jancaitis

Charles E Turner, Jr

Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

High average power scaleable thin-disk laser

In a master oscillator-power amplifier (MOPA) hybrid laser system, the master oscillator (MO) utilizes a Nd,-doped gain medium and the power amplifier (PA) utilizes a diode-pumped Yb,-doped material. The use of two different laser gain media in the hybrid MOPA system provides advantages that are otherwise not available. The Nd-doped gain medium preferably serves as the MO because such gain media offer the lowest threshold of operation and have already been engineered as practical systems. The Yb-doped gain medium preferably serves in the diode-pumped PA to store pump energy effectively and efficiently by virtue of the long emission lifetime, thereby reducing diode pump costs. One crucial constraint on the MO and PA gain media is that the Nd and Yb lasers must operate at nearly the same wavelength. The 1.047 &mgr;m Nd:YLF/Yb:S-FAP &lsqb;Nd:LiYF,/Yb:Sr,(PO,),F&rsqb; hybrid MOPA system is a preferred embodiment of the hybrid Nd/Yb MOPA.

Hybrid solid state laser system using a neodymium-based master oscillator and an ytterbium-based power amplifier

Large neodymium glass laser disks for disk amplifiers such as those used in the Nova laser require an edge cladding which absorbs at 1 micrometer. This cladding prevents edge reflections from causing parasitic oscillations which would otherwise deplete the gain. Nova now utilizes volume-absorbing monolithic-glass claddings which are fused at high temperature to the disks. These perform quite well but are expensive to produce. Absorbing glass strips are adhesively bonded to the edges of polygonal disks using a bonding agent whose index of refraction matches that of both the laser and absorbing glass. Optical finishing occurs after the strips are attached. Laser disks constructed with such claddings have shown identical gain performance to the previous Nova disks and have been tested for hundreds of shots without significant degradation.

Composite polymer-glass edge cladding for laser disks

A method for recycling laser flashlamp radiation in selected wavelength ranges to decrease thermal loading of the solid state laser matrix while substantially maintaining the pumping efficiency of the flashlamp.

Flashlamp radiation recycling for enhanced pumping efficiency and

An electron beam of energy typically 100 keV excites a fluorescer gas which emits ultraviolet radiation. This radiation excites and drives an adjacent laser gas by optical pumping or photolytic dissociation to produce high efficiency pulses. The invention described herein was made in the course of, or under, United States Energy Research and Development Administration Contract No. W-7405-Eng-48 with the University of California.

Method and apparatus for secondary laser pumping by electron beam

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Livermore, CA, United States of America

Howard T Powell