Methods, systems, and apparatus for high energy optical-pulse amplification at high average power

US9065241B2 · kind B2 · utility

Assignee

• Massachusetts Institute of Technology · US

Inventors

• Luis E. Zapata · Livermore, US
• Franz X. Kaertner · Newton, US
• Eduardo Granados Mateo · Cambridge, US
• Kyung-Han Hong · Lexington, US

Key dates

• Filing date: Mar 14, 2013
• Grant date: Jun 23, 2015
• Expiry date: Nov 5, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S2301/02
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An inventive composite optical gain medium capable includes a thin-disk gain layer bonded to an index-matched cap. The gain medium's surface is shaped like a paraboloid frustum or other truncated surface of revolution. The gain medium may be cryogenically cooled and optically pumped to provide optical gain for a pulsed laser beam. Photons emitted spontaneously in the gain layer reflect off or refract through the curved surface and out of the gain medium, reducing amplified spontaneous emission (ASE). This reduces limits on stored energy and gain imposed by ASE, enabling higher average powers (e.g., 100-10,000 Watts). Operating at cryogenic temperatures reduces thermal distortion caused by thermo-mechanical surface deformations and thermo-optic index variations in the gain medium. This facilitates the use of the gain medium in an image-relayed, multi-pass architecture for smoothed extraction and further increases in peak pulse energy (e.g., to 1-100 Joules).