A Rotationally Symmetric Polarized Hollow-Center Laser with High Polarization Purity and Adjustable Polarization Direction

Abstract

The invention discloses a rotationally symmetric polarization hollow laser device with high polarization purity and an adjustable polarization direction. The rotationally symmetric polarization hollowlaser device comprises a negative conical mirror (1), a positive conical mirror (2), a laser gain medium (3), a plane reflector (4), an optically active crystal positive cone (7) and an optically active crystal negative cone (8) which are sequentially arranged, wherein a coupling optical system (5) and a semiconductor laser array (6) are arranged below the plane reflector (4); and the laser gainmedium (3), the positive conical mirror (2), the negative conical mirror (1), the optically active crystal positive cone (7) and the optically active crystal negative cone (8) form a laser resonant cavity, the right end surface of the laser gain medium (3) is an input mirror of the laser resonant cavity, and the optically active crystal negative cone (8) serves as an output coupling mirror of thelaser resonant cavity. The rotationally symmetric polarization hollow laser device enables the light intensity center of a cross section of an output beam of the laser device to have large dark spot size, and the polarization distribution is rotationally symmetric and the polarization direction is continuously adjustable, thereby improving the polarization purity and beam quality of the hollow laser beam.

Description

technical field [0001] The invention relates to the field of laser technology, in particular to a rotationally symmetrical polarization hollow laser with high polarization purity and adjustable polarization direction. Background technique [0002] Rotationally symmetric polarized light is a kind of non-uniformly polarized light whose polarization direction is distributed along the cross-section of the beam for rotationally symmetric distribution. In the center of the beam, the intensity of the center of the beam is zero due to the existence of a phase singularity point and a polarization singularity point. The special intensity distribution and non-uniform polarization distribution of rotationally symmetric polarized light make it useful in applications such as laser processing, surface plasmon excitation, and near-field scanning microscopy. [0003] Various methods have been developed to obtain rotationally symmetric polarized light, mainly including intracavity methods an...

AI Technical Summary

Problems solved by technology

The intracavity method is to set a circular grating mirror or a birefringent crystal and other polarization selection elements in the laser cavity so that the laser can directly output rotationally symmetrical polarized light. not tall

The extracavity method mainly converts linearly polarized or circularly polarized light into rotationally symmetrical polarized light by exciting high-order modes of waveguides, coherent synthesis, and liquid crystal twisting. Purity is not ideal

In addition, the above method can only obtain a polarized beam in a rotationally symmetrical direction, and the polarization direction of the beam cannot be continuously adjusted, which seriously affects the flexibility of the beam application.

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