A semiconductor laser with high power and high beam quality laser

Abstract

A semiconductor laser with high-power and high-beam-quality lasers. An external resonant cavity is built outside the semiconductor gain element, and a collimating optical element, a spectral dispersion element, and a coupling output mirror are sequentially arranged in the external resonant cavity. The semiconductor gain element consists of several active gain regions arranged in parallel in a straight line. One side of each active gain region is coated with a film layer with high reflectivity to the laser wavelength, and the other side is coated with a film layer with high transmittance to the laser wavelength. film layer. The collimating optical element is located behind the side of the semiconductor gain element coated with a high-transmittance film layer, and its central optical axis coincides with the central optical axis of the light beam emitted by the semiconductor optical gain element. The spectral dispersing element is placed at an angle behind the collimating optics. The outcoupling mirror is located behind the spectral dispersion element along the beam propagation direction. The invention improves the mode of laser oscillation and effectively increases the output power of the laser without affecting the quality of the laser beam.

Description

technical field [0001] The invention relates to a power expansion technology of an external cavity semiconductor laser, in particular to a semiconductor laser with high power and high beam quality laser. Background technique [0002] Due to its high brightness, good monochromaticity, good collimation and focusing performance, laser has been widely used in scientific research, military defense, industrial processing, astronomical observation and information dissemination and other fields. The beam quality of the laser is a parameter that describes the focusing and collimation capabilities of the laser during propagation. A laser with high beam quality will get a smaller spot after focusing and a smaller far-field divergence angle after collimation. Therefore, in practice In applications, lasers with high beam quality have always been the direction people are pursuing. However, as the output power of the laser increases, factors such as thermal effects will gradually be ampli...

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Problems solved by technology

However, as the output power of the laser increases, factors such as thermal effects will gradually be amplified, thereby affecting the beam quality of the laser. Therefore, the beam quality and power of the laser have always been in opposition to each other. When developing a laser, the pros and cons of practical applications must be weighed. A trade-off between these two parameters

[0003] Compared with other types of lasers (such as gas lasers and solid-state lasers), semiconductor lasers have higher electro-optical efficiency (no fiber coupling loss or secondary pump loss), low cost (no expensive high-power energy transmission fibers), etc. advantages, but its beam quality will seriously deteriorate with the increase of laser output power, how to effectively expand the output power of semiconductor lasers under the premise of maintaining beam quality has always been a research hotspot in this field

[0004] Semiconductor laser array (bar) technology is a very convenient semiconductor laser power expansion technology. Its principle is to arrange several semiconductor light-emitting units in parallel on the substrate so that the output power of the laser increases linearly with the number of light-emitting units. However, due to The near-field wavefront of the laser beam obtained by this method is divided, so the beam quality is very poor, and it cannot be effectively applied to technical fields such as fiber coupling, welding, and cutting that require high-beam quality lasers.

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