Rofin-sinar UK Ltd.

Rofin-sinar, Inc.

Benjamin Stuart Fulford

Jason Robert Lee

Howard John Baker

David James Lewis Birkin

Apparatus and method for the amplification of a laser beam by pumping a homogenous composite source beam through an amplification medium. A slab crystalline active medium is side-pumped via a pump module having a laser diode bar and an optical assembly. The optical assembly has a fast axis collimator and a lens in the fast axis and an array of slow axis collimators and the lens in the slow axis. The lenses are spaced so that the individual source beams from the emitters are: imaged upon a first facet of the amplification medium; have a beam waist at or near the first facet; are sized to fill the first facet; substantially overlap on the first facet; and are directed so that peripheral source beams undergo total internal reflection on entering the amplification medium. Embodiments of multiple laser diode bars and optical assemblies are described together with double side pumping arrangements.

Laser beam amplification by homogenous pumping of an amplification medium

An optical amplifier which integrates a pre-amplifier and a power amplifier in a single rectangular active medium to enable amplification of low power ultra-short pulses to optimal power levels. A seed beam passes through the amplification medium along a first pre-amplification path making multiple traverses of the medium. It is imaged back along the first path to make a double pass of the medium as a pre-amplifier. The beam is then re-imaged into the medium again on a second power amplification path, making multiple traverses of the medium in a single pass. The paths are independent but overlap so that efficient power extraction is achieved. Embodiments based on all passive components are described.

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Kingston Upon Hull, United Kingdom

Benjamin Stuart Fulford