Patent ID: 7433373

Claim:
An actively Q-switched laser system, comprising: a laser gain medium; an optical pump source for providing an excitation energy to the laser gain medium; a laser resonator for resonating the laser photons emitted from the laser gain medium being positioned therein; and an electro-optic crystal positioned in the laser resonator and functioning as a laser Q-switch for accumulating the photon energy in the laser gain medium under a first state and releasing the energy accumulated in the laser gain medium under a second state; wherein the electro-optic crystal comprises a quasi-phase-matched electro- optic crystal, comprising a periodically poled lithium niobate (PPLN) crystal, a periodically poled lithium tantalite (PPLT) crystal, or a periodically poled potassium titanyl phosphate (PP-KTP) crystal acting as a polarization rotator, and a quarter-wave retarder, a Brewster plate or a polarization-dependent loss element; wherein the electro-optic crystal comprises a plurality of surface electrodes parallel to the direction of the laser beam propagation; and wherein the surface electrodes are applied with a voltage between two successive of them for controlling the polarization direction of the resonant laser beam passing through the area of the electro-optic crystal beneath the surface between the electrodes, thereby switching the laser resonator between the first state and the second state.