Coherent, Inc.

Gerald H Williams

Thomas F Johnston, Jr

James L Hobart

Robert R Naquin

Christopher John Kruger

Charles W Dennett

William P Proffitt

Robert C Rempel

Apparatus for measuring power in a laser-beam includes a transmissive diffuser for diffusely expanding the laser-beam and a photon detector for receiving the diffusely-expanded laser-beam and generating an electrical signal in response thereto. Electronic circuitry including a microprocessor is provided for interpreting the electrical signal as a measure of power in the laser-beam. A display device is provided for displaying the interpreted signal.

Portable laser power measuring apparatus

A method and apparatus for determining the quality of a multimode laser beam (10). In the preferred embodiment, the apparatus includes a lens (32) for creating a transformed or imaged waist from the input beam. The location of the transformed beam waist and its diameter are then determined. These steps can be carried out by chopping the beam using a rotating hub (14) having apertures (36,38) for selectively passing the beam. Preferably, one of the apertures has a pair of 45.degree. knife edges (40,42). The transmission of the beam past the knife edge is monitored by a detector (30). In operation, the lens focal position is varied while the transmission of the beam past the knife edge is monitored in order to locate and measure the diameter of the transformed waist. The diameter of the beam at one other known location is measured. A processor then calculates beam quality by fitting these measurements to a mathematical model. Once the quality of the beam is calculated, the location of the original beam waist and its diameter can be derived. Once all of the beam parameters are derived, the propagation characteristics of the beam can be predicted. In the preferred embodiment, the transformed beam waist is located by taking incremental measurements of beam diameter, at both the front and rear planes of the hub, as the lens is moved a distance at least a great as the diameter of the hub. The diameter measurements are spliced together by the processor to provide an axial profile of the beam over a distance twice as large as the diameter of hub. This data can then be analyzed to find the minimum which corresponds to the location of the transformed beam waist.

Apparatus for measuring the mode quality of a laser beam

A scannable dye laser is provided with an integral wavemeter under computer control. The wavemeter has improved fine and coarse readout components. Incremental laser scans are precisely linked together to provide long, continuous frequency scans. The fine readout of the wavemeter provides a means for accurately piecing together the incremental scans.

Scannable laser with integral wavemeter

Method and apparatus are disclosed in a frequency controlled tunable laser system which may be tuned selectively by an operator to any predetermined output radiation frequency within its operating range and servo-locked to maintain that output frequency, for rapidly and automatically maintaining and reacquiring a predetermined output radiation frequency despite momentary interruptions or perturbations of laser oscillation.

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Applegate, CA, United States of America

Gerald H Williams