Active and passive Q-adjusted single longitudinal mode laser

Abstract

The invention consists of pumping source, cavity, and a group of coupling device set between the pumping source and cavity, and connected with pumping source through optical fiber. The cavity consists of front cavity mirror and back cavity mirror coated with film. The double-doped crystals and active Q-switch are set between the front and back mirrors. A cooling device is set on the double-doped crystals. The invention features using active Q-switch to control the passive Q-switch for getting prelase pulse, and using saturable absorption crystals as longitudinal mode selector for making the solid single longitudinal mode laser work under higher pumping power.

Description

technical field [0001] The invention relates to a single longitudinal mode laser, in particular to an all-solid-state active-passive Q-switched single longitudinal mode laser using a semiconductor laser as a pump source. Background technique [0002] In many application fields such as coherent lidar, micromachining, laser ranging, trace element detection, microsurgery, laser pulse shaping and energy amplification, if the laser pulse has: stable high repetition rate, high peak power, High average power, short pulse width, small pulse intensity drift and pulse shape change, stable single transverse mode and single longitudinal mode, polarization or partial polarization, no mode competition and mode hopping phenomenon, etc., all or part of these characteristics, this It will be more widely used. Q-switching is a common technique for generating laser pulses with high peak power and short pulse duration. The function of the Q switch is to prevent the laser oscillation in the la...

AI Technical Summary

Problems solved by technology

However, injection locking requires that the detuning between the frequency of the injected signal and the frequency of the closest longitudinal mode in the sub-cavity must be less than a certain value, otherwise injection locking will fail

Therefore, in injection locking, there must be an electronic system for feedback control of the cavity lengths of the main cavity and the auxiliary cavity. This system is technically complex, and it still cannot guarantee the long-term stability of injection locking.

[0010] Both active Q-switching and passive Q-switching can achieve single longitudinal mode laser output. Under pulse or continuous pumping conditions, active Q-switching single longitudinal mode laser can be obtained by using pre-laser technology, but the probability of single longitudinal mode is low

In order to improve the working probability of the single longitudinal mode, a detection device is required to detect the formation of the pre-laser pulse, which destroys the stability of the repetition rate, and the cavity length of the active Q-switched pre-laser single longitudinal mode laser needs to use piezoelectric ceramics control, making the system more complex and less practical

The device of passive Q-switched single longitudinal mode laser is simple and easy to use, but it cannot obtain a stable repetition rate and can only work near the threshold. Dong Jun reported a single longitudinal mode laser output with an average power of up to 80 mW in 2000 ( Microwave and Optical Technology Letters, Vol.26, pp124, 2000)

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