Repetitively Q-Switched Laser Pumped by Laser Diodes and and Q-Switched with An Intracavity Variable Speed Moving Aperture.
Patent, Filed 16 Feb 95, patented 18 Jun 96,
DEPARTMENT OF THE NAVY WASHINGTON DC
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A laser is end pumped by laser diodes and is repetitively Q-switched using an intracavity variable speed moving aperture. The aperture apparatus includes a precision motor which drives a pair of matched aperture blades and produces efficient Q-switched operation over a wide range of output powers and repetition rates. Each aperture blade may contain an identical number of transmissive and opaque regions, and two aperture blades may be mounted onto the motor in a manner that allows continuous adjustment of the aperture width. In a preferred embodiment the aperture blades are shaped as circular discs. The laser resonator mode is nearly hemispherical, and the aperture blade is located at or near the laser resonator mode waist. When pumped with the optimum pump flux, efficient repetitively Q-switched operation is obtained as long as the Q-switch opening time is shorter than the pulse build-up time. The pulse build-up time can be calculated, and the Q-switch opening time is defined in accordance with this inventive concept. The Q-switch opening time is a function of the laser resonator mode diameter at the location of the aperture blade and the velocity of the aperture blade as it moves through the resonator mode. The Q-switch opening time is a fraction of the time required for the edge of the aperture blade to traverse the entire resonator mode diameter.
- Lasers and Masers