Dual-wavelength pumping tunable intermediate infrared pulse fiber laser system

Abstract

The invention discloses a dual-wavelength pumping tunable intermediate infrared pulse fiber laser system. The system comprises a pumping source, a pumping coupling lens, an Er < 3 + >: ZBLAN optical fiber, a signal light coupling lens, a beam splitter, an acousto-optic switch, a Littrow grating and an output coupling mirror. According to the invention, an acousto-optic switch modulator and a Littrow grating wavelength tuning modulator are inserted under the free operation of a dual-wavelength pumping low-doped Er < 3 + >: ZBLAN fiber laser, tunable short-pulse mid-infrared fiber laser with stable wavelength is output, and the system can operate at high energy. The system is suitable for output of tunable short-pulse fiber laser with other intermediate infrared wavelengths, and can operate at high energy.

Description

technical field [0001] The invention relates to a dual-wavelength pumped tunable mid-infrared pulse fiber laser system, in particular to an erbium-doped fluoride fiber laser to realize tunable pulsed laser output under dual-wavelength pumping. Background technique [0002] The mid-infrared laser in the near 3-μm band is a good atmospheric absorption window, a concentrated band of thermal radiation energy, and a region with strong water absorption. In environmental monitoring, especially the mid-infrared laser near the 2.8-μm wavelength and a variety of important gas molecules (such as CO, NO 2 、H 2 S, etc.) The absorption peak spectrum overlaps, which can improve the measurement sensitivity. Lasers in this band can also be used in laser surgery, especially pulsed lasers, which can be used as an extremely precise cutting tool to reduce trauma and improve wound healing. Therefore, it has important application value in military, remote sensing, laser medical and other fields...

AI Technical Summary

Problems solved by technology

2.8-μm laser light generated in 4 I 11 / 2 → 4 I 13 / 2 ,because 4 I 11 / 2 Energy level lifetime (6.9-ms) vs. 4 I 13 / 2 The energy level lifetime (9.0-ms) is short, most particles will be in 4 I 13 / 2 accumulation of energy levels, resulting in 4 I 11 / 2 → 4 I 13 / 2 The particle population inversion cannot be formed, which will lead to the phenomenon of self-termination of laser oscillation

[0010] In terms of pulsed lasers, for high-doped ZBLAN fiber laser media, Er-doped 3+ High ion concentration will produce saturable absorption effect, resulting in self-pulse modulation in laser oscillation; high doping concentration will make the preparation process more difficult, resulting in material inhomogeneity. When operating at high energy, material uniformity and internal stress Laser beam depolarization and wavefront distortion will occur, resulting in increased cavity loss, reduced laser efficiency and poor beam quality

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