CN202276060U - Self-Raman frequency conversion self-locking mode solid laser - Google Patents

Abstract

The utility model is suitable to the technical field of laser design, and provides a self-Raman frequency conversion self-locking mode solid laser using a vanadate crystal mixed with a rare earth ion as a laser gain medium, comprising a pumping source and a resonant cavity, wherein inside the resonant cavity there is provided the laser gain medium, the laser gain medium is the vanadate crystal mixed with the rare earth ion, and the front and rear light pass surfaces of the laser gain medium are not vertical to a laser light path. The fundamental frequency laser generated by the laser medium oscillates in the resonant cavity, and simultaneously due to the simulated Raman scattering and self-locking mode characteristic of the fundamental frequency laser, the fundamental frequency laser is converted into a first-order Stokes ultra-short pulse Raman laser. The self-Raman frequency conversion self-locking mode solid laser is simple and compact in structure, is high in efficiency and laser beam quality, stable and reliable in performance, and high in cost performance, and can be used for a seed source of a ultra-short pulse laser amplifier and for ultra-short pulse lasers of other wavelengths which generate yellow light.

Description

A self-Raman frequency conversion self-mode-locked solid-state laser

technical field

The utility model belongs to the technical field of laser design, in particular to a solid laser and a resonant cavity thereof. the

Background technique

Solid-state lasers refer to lasers that use solid-state laser materials as the working substance of the resonator, and are widely used in military, processing, medical and scientific research fields. the

As an important branch of the field of laser and nonlinear optics, the application of optical frequency conversion technology can effectively expand the output laser spectrum of the laser, thereby further broadening the application field of the laser. Among them, the stimulated Raman scattering (Stimulate Raman Scattering, SRS) technology of Raman media has attracted a lot of attention due to its advantages of high efficiency, improved beam quality, and no need for phase matching. The laser spectrum after being dispersed by the Raman medium extends from ultraviolet to near infrared, broadening the range of the laser spectrum. the

For this reason, the solid-state laser provided by the prior art adopts Raman crystal as the Raman medium, so that the solid-state laser is more widely used in information, transportation, measurement, medical treatment, National defense and industrial and agricultural fields. However, although the solid-state lasers using Raman crystals provided by the prior art broaden the range of the laser output laser spectrum, they cannot produce lasers that are mainly used in ultra-high-speed optical communications, massive information storage, photosynthesis research, chemical reaction processes and other fields. Lasers with ultrashort pulses have limited applications. the

Utility model content

The purpose of the utility model is to provide a solid-state laser, aiming to solve the problem that the solid-state laser using Raman crystals provided by the prior art cannot produce laser with ultrashort pulses and has limited application fields. the

The utility model is achieved in this way, a self-Raman frequency conversion self-mode-locked solid-state laser, including: a pump source and a resonant cavity, the resonant cavity has a laser gain medium, and the laser gain medium is vanadium doped with rare earth ions acid salt crystal; the front and rear two light-passing surfaces of the laser gain medium are not perpendicular to the laser light path. the

Further, the resonant cavity includes a pump-end cavity mirror and an output mirror; the pump-end cavity mirror has high transmittance to pump light, high reflection to fundamental frequency light and first-order Stokes light, and the The output mirror is highly reflective to the fundamental frequency light and has transmittance to the first-order Stokes light. the

Further, the resonant cavity is a straight cavity, a three-mirror folded cavity, a Z-shaped folded cavity or an X-shaped folded cavity. the

Further, the vanadate crystals doped with rare earth ions include Nd:YVO ₄ crystals, Nd:GdVO ₄ crystals, Nd:LuVO ₄ crystals, Nd:Gd _x Y _1-x VO ₄ crystals, Nd:Lux _{Y 1 -x} VO ₄ crystals, Nd:Lu _x Gd _1-x VO ₄ crystals, Yb:YVO ₄ crystals, Yb:GdVO ₄ crystals or Yb:LuVO ₄ crystals.

Further, the pumping source includes: a laser diode, a fiber-coupled output semiconductor laser system or other laser light sources. the

Further, the cavity mirror of the resonant cavity is a wedge mirror, a plane mirror, a plano-convex mirror or a plano-concave mirror. the

The utility model adopts the vanadate crystal doped with rare earth ions as the working medium of the resonant cavity, and the front and rear light-passing surfaces of the laser gain medium are not perpendicular to the laser light path, thereby avoiding the influence of the mode-locking effect due to the etalon effect . Therefore, the vanadate crystal doped with rare earth ions not only produces the stimulated Raman scattering effect on the incident laser light, but also can realize the selection of the stimulated Raman scattering light pulse through the Kerr lens effect or saturable Raman gain. Self-mode-locking of lasers to obtain lasers with ultrashort pulses. the

Description of drawings

Fig. 1 is a schematic structural diagram of a solid-state laser provided by the present invention. the

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model. the

The utility model adopts the vanadate crystal doped with rare earth ions as the working medium of the resonant cavity, and sets the front and rear light-passing surfaces of the laser gain medium to be non-perpendicular to the laser light path. The vanadate crystal doped with rare earth ions is While generating the stimulated Raman scattering effect on the incident laser light, it can also generate a strong Kerr lens effect, thereby obtaining laser light with ultrashort pulses. the

Fig. 1 shows the principle structure of the solid-state laser provided by the present invention, and for the convenience of description, only the parts related to the present invention are shown. the

The solid-state laser provided by the utility model includes a pump source 1 and a resonant cavity 2, wherein the resonant cavity 2 has a laser gain medium 22 inside. The pump source 1 is used to generate pump light and focus the pump light onto the working medium 22 in the resonant cavity 2, wherein the resonant cavity 2 can be a straight cavity, a triple-mirror folded cavity, a Z-shaped folded cavity, or an X-shaped folded cavity ; The laser gain medium 22 is a vanadate crystal doped with rare earth ions, including Nd:YVO ₄ crystal, Nd:GdVO ₄ crystal, Nd:LuVO ₄ crystal, Nd:Gd _x Y _1-x VO ₄ crystal, Nd:Lu _x One or more of Y _1-x VO ₄ crystals, Nd: Lu _x Gd _1-x VO ₄ crystals, Yb: YVO ₄ crystals, Yb: GdVO ₄ crystals, Yb: LuVO ₄ crystals.

Above-mentioned pumping source 1 can comprise laser diode, fiber-coupled output semiconductor laser system or other laser light sources, the structure of pumping source 1 is shown in Fig. System 12. the

The resonant cavity 2 also includes a pumping end cavity mirror 21 and an output mirror 23, the pumping end cavity mirror 21 is highly transmissive to pump light, highly reflective to fundamental frequency light and first-order Stokes light, and the output mirror 23 is highly reflective to fundamental frequency light and has transmittance to first-order Stokes light. the

The above-mentioned pump end cavity mirror 21 can be a wedge-shaped mirror, a plane mirror, a plano-convex mirror or a plano-concave mirror. In order to avoid forming the etalon effect, increase the number of longitudinal modes oscillating in the resonant cavity, thereby improving the mode-locking effect, in the utility model , at least one of the front and rear light-passing surfaces 221 and 222 of the laser gain medium 22 is not perpendicular to the laser light path, specifically, the opposite plane between the pump end cavity mirror 21 and the laser gain medium 22 can be set to be non-parallel, and/or The opposing faces between the laser gain medium 22 and the output mirror 23 are not parallel. the

The utility model adopts the vanadate crystal doped with rare earth ions as the working medium of the resonant cavity 2, and the self-locking characteristic of the vanadate crystal doped with rare earth ions is based on the Kerr lens mode locking of the vanadate crystal, or based on the saturable pull Selection of Mann gain for stimulated Raman scattered light pulses. It is well known that vanadate crystals doped with rare earth ions have excellent third-order nonlinear characteristics, which can produce stimulated Raman scattering effects on incident laser light in the visible and near-infrared spectral ranges, and realize the output of self-Raman frequency-converted lasers, and This structure is beneficial to realize the mode matching of the fundamental frequency light and the Stokes light, lower the threshold, improve the stability and conversion efficiency of the system, and simplify the cavity structure of the resonant cavity. In order to apply the solid-state laser to generate laser with ultrashort pulses (i.e. to achieve mode-locking of the laser), the working medium needs to have a large nonlinear coefficient to provide a strong enough self-focusing effect. Therefore, vanadic acid doped with rare earth ions Salt crystals can produce a strong Kerr lens effect (Kerr-lens effect) while producing stimulated Raman scattering effect on the incident laser light, thereby realizing Kerr lens mode locking (KLM), to obtain laser light with ultrashort pulses. the

Taking the vanadate crystal as YVO ₄ crystal as an example, the experimental data shows that the nonlinear refractive index of YVO ₄ crystal is 1.9*10 ^-15 cm2/W, which is about the same as that of the commonly used Ti:sapphire crystal that produces the Kerr lens effect. Since the nonlinear refractive index is a parameter that characterizes the strength of the self-focusing effect caused by the Kerr lens effect, the YVO ₄ crystal is a highly efficient Kerr lens self-mode-locking working medium.

In one embodiment of the present utility model, the output mirror 23 will undergo its own stimulated Raman scattering effect and Kerr lens mode-locking effect, with a wavelength of 1.17 μm, a repetition rate of GHz level, and a pulse width of picosecond level The ultrashort pulse laser is output to the outside of the resonant cavity 13 based on vanadate crystals. For this reason, the wavelength of the pump light generated by the pump source 1 is 808nm; Transparent, highly reflective dielectric film for 1064nm incident laser light and 1.17μm incident laser light; on the laser gain medium 22, the incident light-passing end surface and the exiting light-passing end surface of the pump light optical path after focusing along the focusing coupling system 12 are respectively coated with 808nm incident light Laser, 1064nm incident laser and 1.17μm incident laser highly transparent dielectric film; the output mirror 23 is coated with a dielectric film that is highly reflective to 1064nm incident laser and partially reflective to 1.17μm incident laser. the

The ultra-short pulse laser emitted by the solid-state laser provided by this embodiment of the utility model can produce an ultra-short pulse yellow laser with a wavelength of 588nm for medical treatment, spectral analysis and other fields after frequency doubling. the

In another embodiment of the present utility model, the output mirror 23 will undergo self-stimulated Raman scattering effect and Kerr lens mode-locking effect, with a wavelength of 1.52 μm, a repetition rate of GHz order, and a pulse width of picosecond The ultra-short pulse laser of the level is output to the outside of the resonant cavity 13 based on vanadate crystals. For this reason, the wavelength of the pump light generated by the pump source 1 is 808nm; Highly transparent to 1064nm incident laser light, and highly reflective to 1342nm incident laser light and 1.52μm incident laser light; on the laser gain medium 22, the incident light-passing end face and the exiting light-passing end face of the pump light optical path after focusing along the focusing coupling system 12 are respectively Coated with a dielectric film that is highly transparent to 808nm incident laser, 1064nm incident laser, 1342nm incident laser and 1.52μm incident laser; the output mirror 23 is coated with high transmittance to 1064nm incident laser, high reflection to 1342nm incident laser and 1.52μm incident laser reflective dielectric film. The ultra-short pulse laser emitted by the solid-state laser in this embodiment of the utility model can be applied to the field of optical communication, or used as a seed source of an ultra-short pulse laser amplifier. the

The utility model adopts the vanadate crystal doped with rare earth ions as the working medium of the resonant cavity. At least one of the front and rear light-passing surfaces of the vanadate crystal doped with rare earth ions is not perpendicular to the laser light path. While the stimulated Raman scattering effect is generated, the self-mode-locking of the laser can be realized through the selection of the stimulated Raman scattering light pulse by the Kerr lens effect or the saturable Raman gain, thereby obtaining a laser with an ultrashort pulse . the

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models. the

Claims (6)

1. A self-Raman frequency conversion self-mode-locked solid-state laser, comprising: a pump source and a resonant cavity, characterized in that: there is a laser gain medium in the resonant cavity, and the laser gain medium is the vanadate doped with rare earth ions Crystal; at least one of the front and rear light-passing surfaces of the laser gain medium is not perpendicular to the laser light path. 2. self-Raman frequency conversion self-mode-locked solid-state laser as claimed in claim 1, is characterized in that: The resonant cavity includes a pump end cavity mirror and an output mirror; the pump end cavity mirror has high transmission to pump light, high reflection to fundamental frequency light and first-order Stokes light, and the output mirror is The fundamental frequency light is highly reflective, and has a transmittance to the first-order Stokes light. 3. self-Raman frequency conversion self-mode-locked solid-state laser as claimed in claim 1, is characterized in that: The resonant cavity is a straight cavity, a three-mirror folded cavity, a Z-shaped folded cavity or an X-shaped folded cavity. 4. self-Raman frequency conversion self-mode-locked solid-state laser as claimed in claim 1, is characterized in that: The vanadate crystals doped with rare earth ions include Nd:YVO ₄ crystals, Nd:GdVO ₄ crystals, Nd:LuVO ₄ crystals, Nd:Gd _x Y _1-x VO ₄ crystals, Nd:Lu _x Y _1-x VO 4 crystals, ₄ crystals, Nd: _Lux Gd _1-x VO ₄ crystals, Yb:YVO ₄ crystals, Yb:GdVO ₄ crystals or Yb:LuVO ₄ crystals. 5. The self-Raman frequency conversion self-mode-locked solid-state laser according to claim 1, wherein the pumping source comprises: a laser diode, a fiber-coupled output semiconductor laser system or other laser light sources. 6. self-Raman frequency conversion self-mode-locked solid-state laser as claimed in claim 2, is characterized in that: The cavity mirror of the resonant cavity is a wedge mirror, a plane mirror, a plano-convex mirror or a plano-concave mirror. the

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