Medium infrared parameter converter

Abstract

The invention relates to a medium infrared parameter converter belonging to the technical field of laser and suitable for electro-optical countermeasures, chemical and biological threats detection, imaging laser radar, trace gas detection and the like. A main optical path of the medium infrared parameter converter is sequentially provided with a laser, a light splitting device, a medium infrared parameter oscillator, a two-color coupling mirror and a medium infrared parameter amplifier, wherein the light splitting device comprises a wave plate, a polarization element and a light splitting reflector; the laser is a pump laser, the light splitting device divides pump light into two paths, one path is pumped into the medium infrared parameter oscillator to generate medium infrared parameter seed light and the other path is pumped to a human eye safe light parameter converter to generate a human eye safe laser; and after subjected to time synchronization, the medium infrared seed light and the human eye safe laser enter the medium infrared parameter amplifier through the two-color coupling mirror. The invention has the advantage of providing the medium infrared parameter converter of high light beam quality and high-energy medium infrared laser output.

Description

technical field [0001] The invention relates to a mid-infrared optical parameter converter, which belongs to the field of laser technology, specifically relates to mid-infrared nonlinear frequency conversion technology, optical parametric oscillator / amplifier technology, and is suitable for photoelectric countermeasures, biochemical threat detection, imaging laser radar, trace gas detection etc. Background technique [0002] The mid-infrared laser in the 3-5μm band is a window of the atmosphere, which has strong penetrating power to fog, smoke and dust, etc., and is less absorbed by gas molecules and scattered by suspended matter when transmitted at sea level, and is sensitive to most important hydrocarbon gases. and other toxic molecules have cavity-absorbing properties. Therefore, using these characteristics of mid-infrared lasers, the 3-5 μm band can be used in technical fields such as photoelectric countermeasures, biochemical threat detection, imaging lidar, and trace ...

AI Technical Summary

Problems solved by technology

It can be seen from the above that it is difficult to obtain high-power mid-infrared lasers by directly pumping the KTA optical parametric oscillator at 1.06 μm

[0005] 3. The US patent "monolithic serial optical parametric oscillator" (Patent No. US6344920 B1) uses a 1.06μm laser to pump the first-stage non-critical phase-matched KTA optical parametric oscillator to generate a 1.53μm eye-safe laser, and then uses a 1.53μm eye-safe Laser-pumped second-stage non-critical phase-matched KTA optical parametric oscillator to achieve 2.59μm signal light and 3.76μm idler light output. This method increases the wavelength of pump light to make the quantum number loss between signal light and idler light Reduced, thereby improving the conversion efficiency of mid-infrared idler light. In this patent, the two-stage optical parametric oscillator shares a resonant cavity through the method of lens coating, which simplifies the structure but increases the difficulty of coating

At present, the coating level is limited, and the laser damage threshold of the coating layer is difficult to meet the needs of high-energy laser pumped optical parametric oscillators

[0006] 4. The optical parametric oscillators described in 1, 2 and 3 above also have the following things in common: According to the characteristics of the optical parametric oscillator, due to the threshold effect of the optical parametric oscillator, only when the pump optical power density exceeds the threshold can the Effective optical parametric conversion, which will cause part of the energy of the pump light pulse to be lost; in addition, in high-energy optical parametric oscillators, in order to avoid laser damage to the cavity mirror film and nonlinear crystal, the spot of the pump light must If it is large enough, this will lead to a high Frell number in the optical parametric oscillator resonator, which will cause high-order transverse mode parametric optical oscillations and cause the quality of the output laser beam to deteriorate

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