Phase conjugation laser resonator cavity

Abstract

A phase conjugation laser resonator cavity comprises a flat mirror and a phase conjugation mirror. A gain medium is placed in the laser resonator cavity and close to the flat mirror, a transmitting phase plate and a concave spherical mirror are combined to form the phase conjugation mirror, and the transmitting phase plate is a first-order binary optical element, namely, an annular optical element is arranged on a centrally symmetric optical round plate. By beam shaping in the cavity, a laser beam in approximate flattened Gaussian distribution directly serves as an output mode of the cavity, and the extraction efficiency of a laser device or a laser amplifier can be greatly improved by the aid of a large mode volume.

Description

Technical field [0001] The laser resonant cavity related to the present invention, in particular a phase conjugate laser resonant cavity, can be used for various gain media, pumping lasers and laser amplifiers, and realizes the laser output of approximately flat-top Gaussian distribution. Background technique [0002] The geometric structure of the laser resonant cavity determines the spatial distribution characteristics of the laser optical field generated by it. Most low-gain lasers use a stable Fabry-Perot cavity to establish a stable laser mode. Although this type of cavity is designed with low fundamental mode loss, it has several inherent shortcomings: [0003] 1. In order to ensure sufficient mode discrimination between the fundamental mode and the high-order mode, a small aperture diaphragm is usually added in the cavity to reduce the Fresnel number of the resonant cavity and increase the diffraction loss of the high-order mode; [0004] 2. The fundamental mode spot has a Ga...

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Problems solved by technology

[0004] 2. The fundamental mode spot is Gaussian distributed and the mode volume is small, and the overlapping area with the gain medium is small, and the gain medium cannot be fully utilized, which limits the further improvement of the efficiency of the laser or amplifier;

Therefore, the flat-topped Gaussian distribution of the laser beam is not the intrinsic mode of oscillation of the spherical mirror laser resonator, and the conventional laser resonator design cannot achieve (at least not as a single mode) output of the flat-topped Gaussian laser beam.

[0007] The laser beam with flat-top Gaussian distribution is generally generated by beam shaping outside the resonator cavity, that is, by selecting a suitable amplitude modulation element (soft edge diaphragm, liquid crystal light valve), but it cannot be achieved during the beam shaping process outside the cavity. Avoid energy loss, which greatly affects the total output efficiency of the laser or amplifier

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