Critical angle rotating prism Q-switch
AssigneeHughes Aircraft Company
InventorDonald R. Dewhirst
Life of this patent
Estimating the term…
Abstract
A CO.sub.2 TEA laser Q-switch uses an intra cavity rotating prism (70) with internally reflecting surfaces (76, 78) at near the critical angle to produce a variable optical loss such that the gain of the laser is switched as the prism rotates through the critical angle. The nitrogen tail portion of the laser output pulse can be eliminated by switching the gain just after the main pulse at the beginning at the tail. An opto-electronic timing device (100), which includes a graded index glass rod (101) rotating with the Q-switch prism, generates a pulse (88) to initiate the laser discharge at the proper lead time before the prism switches the resonator gain.
Claims4
Apparatus for controlling the output of a pulse laser device comprising:
- a laser device having an active medium and means for exciting said medium for producing a laser output, a prism Q-switch and means for rotating said prism, and first and second resonator mirrors,
- said active medium and said prism being interposed between said first and second mirrors,
- said first and second resonator mirrors having an arrangement which defines an optical path through said active medium and through said prism, said mirrors further being aligned optically parallel to one another with respect to said optical path, and
- said prism having at least one internal reflecting surface upon which said optical path is reflected at the critical angle once for each revolution of the prism, for enabling the optical loss associated with said internal reflection to be changed when the internal reflection is swept through the critical angle.
Apparatus for controlling the output of a pulse laser device comprising:
- a laser device having an active medium and means for exciting said medium for producing a laser output, a prism Q-switch and means for rotating said prism, and first and second resonator mirrors;
- said active medium and said prism being interposed between said first and second mirrors;
- said first and second resonator mirrors having an arrangement which defines an optical path through said active medium and through said prism, said mirrors further being aligned optically parallel to one another with respect to said optical path;
- and
- said prism having at least one internal reflecting surface upon which said optical path is reflected at the critical angle once for each revolution of the prism, for enabling the optical loss associated with said internal reflection to be changed when the internal reflection is swept through the critical angle, said prism comprising entrance and exit faces with two parallel surfaces, in which the laser beam is internally reflected at the critical angle simultaneously for said two parallel surfaces.
Dependencies are inferred from the claim text.