A High Peak Power Pulse Thulium-doped Laser

Abstract

The invention provides a high-peak power pulse thulium-doped laser, which comprises a thulium-doped fiber seed laser for outputting thulium-doped pulse seed laser, a first fiber amplifier for carrying out power pre-amplification on the thulium-doped pulse seed laser and outputting the thulium-doped laser after power pre-amplification to a frequency selector, the frequency selector for reducing a repetition frequency of the thulium-doped laser after power pre-amplification or selecting a proper repetition frequency, a second fiber amplifier for carrying out power pre-amplification again on the thulium-doped laser after frequency selection to meet requirements of a thulium-doped solid state amplifier, and the thulium-doped solid state amplifier for carrying out power amplification on the thulium-doped laser after power pre-amplification again and outputting the amplified thulium-doped laser. The high-peak power pulse thulium-doped laser adopts an amplification structure which combines the fiber and the solid to carry out power amplification on the thulium-doped laser, and thus the peak power and the average power of a 2-micrometer band pulse thulium-doped laser can be effectively improved.

Description

technical field [0001] The invention belongs to the field of high-power mid-infrared laser generation, in particular to a high peak power pulsed thulium-doped laser. Background technique [0002] Since the 2-micron band thulium-doped laser is in the eye-safe band, near-infrared atmospheric window, water and special gas absorption band, it can be widely used in national defense technology, biomedicine, atmospheric remote sensing, laser radar, polymer non-metallic material processing, environment Control and near-mid-infrared scientific research and many other fields. In addition, because the quartz matrix material of thulium-doped fiber can easily achieve high-power pulse output, it can be used as a good laser source for mid-infrared nonlinear research. Due to many potential applications in the mid-infrared band, 2-micron thulium-doped fibers and solid-state lasers have become research hotspots in recent years. [0003] For all-fiber pulsed thulium-doped lasers, although th...

AI Technical Summary

Problems solved by technology

When it is used for power amplification, nonlinear effects such as stimulated Raman scattering (Stimulated Raman Scattering, SRS) and self-phase modulation (Self-phase Modulation, SPM) are easily generated at higher peak power, especially stimulated Raman Scattering causes a large nonlinear broadening of the frequency domain of the laser, which greatly affects the quality of the fiber laser, making the output peak power less than 100 kilowatts.

At the same time, due to the strong infrared absorption of the quartz fiber in the 2 micron thulium-doped fiber laser, the loss index increases after the wavelength is greater than about 2.2 microns, so that the wavelength red shift caused by SRS increases the laser loss, and the continuous heat accumulation will damage the laser system. At the same time, due to nonlinear frequency conversion, it is difficult to further increase the laser output power at the signal wavelength

In addition, chirped-pulse amplification (CPA) is also used to achieve high peak power output of thulium-doped fiber laser, but the introduction of high-precision grating will undoubtedly increase the difficulty, practicability and cost of the system

[0004] Although the existing solid-state thulium-doped lasers can achieve a high peak output of hundreds of megawatts, they all use CPA technology. The complex spatial structure and high-precision grating undoubtedly increase the difficulty of the system and limit its practicability.

In addition, although the Q-switched solid structure achieves a peak power of megawatt level, the pulse width is nanoseconds, the repetition frequency is extremely low (<100Hz), and the average power is only watt level, which also limits the use of 2-micron lasers in ultra- Demand for high average power in fast laser processing, nonlinear frequency conversion, etc.

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