Spectra-physics Gmbh

Ralph R Jacobs

Alan B Petersen

Shinan-Chur S Sheng

Jeffrey L Kaiser

A large number of semiconductor laser sources coupled with tapered fibers provide a high energy density output for the purpose of longitudinal pumping of a solid state gain medium in an unstable resonator. Each semiconductor laser source generates a beam of radiation at the pump wavelength having characteristic lateral and transverse widths. A plurality of light transmitting fibers, each fiber having an input end and an output end, is coupled with the semiconductor laser sources for delivering the light from a remote location to pump the gain medium. The input end of each fiber has a cross-section substantially matching the transverse and lateral widths of the beams generated by the corresponding semiconductor laser source, and is coupled to receive the beam of radiation generated by a corresponding semiconductor laser source. The output ends of the light transmitting fibers are bundled to deliver the beams coupled into the fibers as a composite light source having a high energy density. Hundreds of watts of pump energy can be delivered to an unstable resonator design with a solid state gain medium from a remotely mounted and cooled array of semiconductor lasers.

High power diode-pumped solid state laser with unstable resonator

A commercial near resonant laser system with a trivalent rate earth ion doped solid state host, such as Nd:YAG, is pumped at an energy sufficient to excite the electrons from the ground level directly to the upper laser level. The laser system is then tuned to a transition from the upper laser level back to the ground level to produce high power output beams. Because the ground level will include a plurality of 'Stark split levels', the necessary population inversions can be maintained and laser energy generated. However, the difference between the Stark split level from which the electrons are excited to the upper laser level, and the Stark split level to which the electrons decay in the light producing transition from the upper laser level, is slight. Thus, energy dissipated in heat as electrons decay in non-lasing transitions is minimized.

Near resonant Nd.sup.3+, solid state laser system

An endbell assembly operatively associated with a laser body includes a metal endbell component sealed to a crystalline endbell component which terminates with a crystalline optical component. The crystalline endbell and crystalline optical component are hermetically sealed without using a frit. This is achieved by polishing and a modified optical contacting technique whereby the optical component and crystalline endbell component are polished to a flatness of about 1/2 wavelength of light, placed in a contacting position and then thermally cycled at a temperature of about 400.degree.-500.degree. C. for about 1 to 10 hours, forming a substantially uniform unitary body. This seal is mechanically strong and minimizes the introduction of contaminants into the endbell assembly. In one embodiment, the crystalline endbell component is metallized and braze-sealed to the metal endbell component. In another embodiment, the two endbell components are hermetically sealed by modified optical contact and thermal cycling.

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Fremont, CA, United States of America

Ralph R Jacobs