Supercontinuum variable frequency laser based on PPLN crystal

Abstract

The invention discloses a supercontinuum variable frequency laser based on PPLN crystals. The laser is composed of a near infrared supercontinuum pumping source, a lens group, PPLN crystals, a temperature control system, a precision adjusting frame and an off-axis parabolic reflector; the lens group is a collimation focusing system formed by a first lens and a second lens; the output end of the near infrared supercontinuum pumping source is located at the focus of the incident surface of the first lens; the PPLN crystals are located in the temperature control system, and the incident end faceis located at the focus of the incident surface of the second lens; the focus of the off-axis parabolic reflector is located at the focus of the incident surface of the second lens, and a center smallhole is coaxial with the output end of the near infrared supercontinuum pumping source, the center of the first lens, the center of the second lens and the centers of the PPLN crystals. According tothe laser, output optical spectrum simultaneously covering visible light, near infrared and middle infrared wave ranges can be achieved by using the near infrared supercontinuum pumping source, the double frequency, sum frequency and difference frequency effects among the PPLN crystals, self-phase position modulation and a stimulated Raman scattering effect. The structure of the laser is compact and the adjustment is simple.

Description

technical field [0001] The invention relates to a supercontinuum frequency conversion laser system, in particular to a PPLN crystal-based supercontinuum frequency conversion laser. Background technique [0002] In recent years, supercontinuum has played an increasingly important role in the fields of environmental monitoring, meteorological detection, biomedicine, material processing, national defense and security due to its high beam quality of ordinary laser light sources and ultra-wide spectral characteristics of white light sources. At present, in terms of spectrum expansion, there have been reports of supercontinuum light sources in the ultraviolet, visible, near-infrared, short-wave infrared, and mid-infrared bands, and they are gradually commercialized. Usually visible light, near-infrared and short-wave infrared supercontinuum are generated in silica-based optical fibers, and mid-infrared supercontinuum are generated in soft glass optical fibers, such as fluoride opt...

AI Technical Summary

Problems solved by technology

However, due to the large absorption loss of the silica fiber in the infrared band, and the large loss of the soft glass fiber in the visible and near-infrared bands, it is difficult for the supercontinuum light source based on fiber pumping to simultaneously cover the visible, near-infrared and mid-infrared bands. Ultra-wideband supercontinuum output

In addition, due to the huge melting point difference between the silica fiber and the soft glass fiber, it is difficult to fuse and taper between the silica fiber and the soft glass fiber, so it is also difficult to realize the beam combining of visible light, near-infrared and mid-infrared bands by combining beams output

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