Acoustic-optic Q-switched frequency double laser employing electro-optic switch to control laser output

Abstract

The present invention provides an acoustic-optic Q-switched frequency double laser employing an electro-optic switch to control laser output. The laser comprises a first total reflector, an acoustic-optic Q-switched crystal, a Brewster polarizer, a folding endoscope, an acoustic-optic Q-switched switch, a LD target bar array, a quartz polarization rotator, an Nd:YAG crystal bar, a second total reflector, a frequency double crystal and an output mirror. The first total reflector, the acoustic-optic Q-switched crystal, the Brewster polarizer and the folding endoscope are coaxially arranged, thefolding endoscope, the acoustic-optic Q-switched switch, the LD target bar array, the quartz polarization rotator and the output mirror are coaxially arranged, and the output mirror, the frequency double crystal and the second total reflector are coaxially arranged. The acoustic-optic Q-switched frequency double laser employing an electro-optic switch to control laser output employs a Z-shaped folding cavity to shorten the size of the device, wherein one folding mirror is taken as an inner cavity frequency double laser output mirror, the highlight high conversion efficiency and the frequency double efficiency are maintained in an acoustic-optic Q-switched mode.

Description

technical field [0001] The invention relates to the technical field of lasers, in particular to an acousto-optic Q-switched frequency-multiplied solid-state laser that uses an electro-optical switch to control laser output. Background technique [0002] In laser processing, laser radar and other application fields, the use of acousto-optic Q-switched high-power QCW diode-pumped lasers requires frequent switching of the laser beam output switch state. [0003] Acousto-optic Q-switching is the principle of diffraction effect when light passes through the equivalent optical phase grating formed by the acousto-optic medium (usually fused silica material) modulated by ultrasonic waves. When ultrasonic waves are loaded in the acousto-optic medium, due to the Diffraction makes the cavity in a state of high loss and low Q value, and the number of energy-level-reversed particles on the doped ions in the laser gain medium can be gathered in a large number. When the ultrasonic wave is ...

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Problems solved by technology

In this case, from an electronic point of view, the laser drive power supply may generate an instantaneously high peak pulse current due to the rapid switching of the signal. If the overcurrent will damage the LD pump module, there is a potential for irreversible damage to the laser. Risk; from a physical point of view, due to the objective existence of the thermally induced birefringence and thermal lens effect of the laser crystal rod, the heat distribution of the laser crystal rod along the axial and radial directions is different after each power-on of the laser, usually It takes a period of time after the light is emitted to reach a relative thermal equilibrium steady state. When power-on-power-off-power on each time, the time for this heat distribution to tend to a steady state is bound to be different, and each time it will tend to a different Due to the new thermal balance steady state in the last power-on state, this also leads to inconsistent beam quality of each output laser, and even the output direction of the laser may jitter within a certain range of the central optical axis, that is, the degree of non-parallelism of the laser output Inconsistency, especially in high-power, high-repetition-frequency pulsed lasers, it can be clearly seen from the CCD imaging spot that the laser spot image always presents irregular changes, and the center of the spot will also follow the floating

[0005] In some laser precision marking and laser fine processing applications, the above-mentioned problems may lead to changes in the size of the laser focal spot or changes in the position of the spot in some applications that require high precision, which will affect the quality of laser processing ; This is often one of the main reasons why some laser marking equipment is prone to failure or laser burnout

On the other hand, in the military laser imaging radar, when it comes to long-distance laser active imaging, the inconsistency between the quality of the laser beam and the optical axis caused by the above problems may also affect the tracking target or imaging quality

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