阅读说明：本技术 一种电光调q腔内倍频亚纳秒脉冲绿光激光器 (Electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser ) 是由 于广礼 丁建永 肖湖福 郭忠纪 周军 于 2019-12-18 设计创作，主要内容包括：本发明公开了一种电光调Q腔内倍频亚纳秒脉冲绿光激光器,包括：泵浦源、泵浦耦合元件、偏振分光棱镜、激光增益介质、λ/4波片、电光开关、基频谐振腔反射镜、谐波分离境、倍频晶体和基频/倍频谐振腔反射镜。本发明通过短腔结构、腔内倍频、电光调Q方式,实现了高倍频效率的亚纳秒脉冲绿光激光输出,可以直接用于需要亚纳秒脉冲绿光激光器的场合；通过腔内倍频的方式,实现亚纳秒脉冲输出,具有结构紧凑、效率高、稳定可靠、成本低等优点。(The invention discloses an electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser, which comprises: the laser comprises a pumping source, a pumping coupling element, a polarization beam splitter prism, a laser gain medium, a lambda/4 wave plate, an electro-optical switch, a fundamental frequency resonant cavity reflector, a harmonic isolation environment, a frequency doubling crystal and a fundamental frequency/frequency doubling resonant cavity reflector. The invention realizes the output of sub-nanosecond pulse green laser with high frequency doubling efficiency by a short cavity structure, intracavity frequency doubling and electro-optical Q-switching modes, and can be directly used in occasions needing the sub-nanosecond pulse green laser; through the mode of intracavity frequency doubling, realize subnanosecond pulse output, have compact structure, efficient, reliable and stable, advantage such as with low costs.)

1. An electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser is characterized by comprising: the laser comprises a pumping source, a pumping coupling element, a polarization beam splitter prism, a laser gain medium, a lambda/4 wave plate, an electro-optical switch, a fundamental frequency resonant cavity reflector, a harmonic isolation environment, a frequency doubling crystal and a fundamental frequency/frequency doubling resonant cavity reflector; the pump light emitted by the pump source is focused into the gain medium through the pump coupling element, the polarization beam splitter prism, the fundamental frequency resonant cavity reflector and the fundamental frequency/frequency doubling resonant cavity reflector form an L-shaped folded resonant cavity, the lambda/4 wave plate and the electro-optical switch are arranged on one arm of the folded cavity, and the harmonic isolation environment and the frequency doubling crystal are arranged on the other arm of the resonant cavity.

2. The electro-optically Q-switched intracavity frequency doubling sub-nanosecond pulsed green-light laser of claim 1, wherein the pump source output mode is spatial light output or fiber coupled output, and the pump mode is pulsed pump or continuous pump.

3. The electro-optically Q-switched intracavity frequency doubling sub-nanosecond pulsed green laser of claim 1, wherein the pump coupling element is configured as a single lens or a lens assembly to couple the pump light into the laser gain medium at a certain spot size.

4. The electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser device as claimed in claim 1, wherein the resonant cavity of the laser device is an L-shaped folded cavity structure, the polarization beam splitter prism is used as a folded mirror of the resonant cavity, the polarization beam splitter prism simultaneously functions as a polarizer and a folded mirror of the resonant cavity in the resonant cavity, and the light-transmitting surface of the polarization beam splitter prism needs to be coated with a pump light antireflection film.

5. The electro-optically Q-switched intracavity frequency-doubling subnanosecond pulse green laser device as claimed in claim 1, wherein the laser gain medium is Nd: YVO₄Crystal, Nd: GdVO₄Crystal, Nd: YAG crystal, Nd: YLF crystal, can output 1 μm wavelength laser crystal.

6. The electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser device as claimed in claim 1, wherein the laser gain medium and the λ/4 wave plate laser electro-optical switch are arranged on one arm of the folding cavity, and are cooperated with the polarization beam splitter prism to realize electro-optical Q-switching; the harmonic separation mirror and the frequency doubling crystal are arranged on the other arm of the resonant cavity, so that the polarization matching of the polarization output of the fundamental frequency light and the frequency doubling of the frequency doubling crystal is realized, and the maximum frequency doubling efficiency is realized.

7. The electro-optically Q-switched intracavity frequency doubling subnanosecond pulsed green-light laser as claimed in claim 1, wherein the laser operates in an electro-optically Q-switched mode, the Q-switched mode being a pressurized electro-optical Q-switched mode or a de-pressurized electro-optical Q-switched mode.

8. The electro-optically Q-switched intracavity frequency-doubled sub-nanosecond pulsed green-light laser of claim 1, wherein the electro-optical on-light is an RTP electro-optical switch, a BBO electro-optical switch, an LGS electro-optical switch, an LN electro-optical switch, or a KD x P electro-optical switch.

9. The electro-optic Q-switched intracavity frequency doubling subnanosecond pulse green laser device as claimed in claim 1, wherein the frequency doubling mode is intracavity frequency doubling, and the phase matching mode of the frequency doubling crystal can be critical phase matching or non-critical phase matching; the output mode of the frequency doubling light is that a harmonic separation mirror is inserted between the polarization beam splitter prism and the frequency doubling crystal, the incident angle of the harmonic separation mirror is 45 degrees or other angles, the passing of the fundamental frequency light can be realized, and the frequency doubling light is output; the frequency doubling crystal is LBO crystal, KTP crystal, PPLN crystal, BBO crystal.

Technical Field

The invention relates to the technical field of laser, in particular to an electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser.

Background

The sub-nanosecond pulse green laser is a green laser with the pulse width smaller than 1ns, has the advantages of narrow pulse width, high peak power and the like compared with the traditional Q-switched nanosecond pulse laser (with the pulse width of 10-100 ns), and can reduce the heat affected zone of processing and improve the processing efficiency for laser micro-nano processing application; corresponding to the application of laser ranging, the ranging precision and the ranging distance of subnanosecond pulse width laser can be improved by several times to dozens of times compared with those of dozens of seconds of pulse width laser under the same energy. Compared with an infrared pulse laser, the laser has the advantages of short wavelength and the like, and is widely applied to laser marine radar, laser fine processing, laser medical treatment, nonlinear optics and the like. Common subnanosecond pulse lasers are produced by passive Q-switched microchip lasers, short-cavity electro-optic Q-switched lasers, mode-locked lasers, cavity dumping, SBS compressed pulse width, electro-modulated semiconductor lasers, etc. The traditional subnanosecond pulse green laser is generally realized by frequency doubling outside a cavity, the frequency doubling efficiency is in direct proportion to the peak power density of fundamental frequency light, and in order to improve the frequency doubling efficiency, a shaping optical element is added between a fundamental frequency device and a frequency doubling device in some applications, so that the whole light path has the defects of complex structure, low light-light conversion efficiency, large size and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing an electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser which can realize subnanosecond pulse green laser output with high efficiency and compact structure, thereby meeting the application in the fields of laser micromachining, laser ranging, laser medical treatment, scientific research and the like.

In order to solve the technical problem, the invention provides an electro-optically Q-switched intracavity frequency doubling subnanosecond pulse green laser, which comprises: the laser comprises a pumping source, a pumping coupling element, a polarization beam splitter prism, a laser gain medium, a lambda/4 wave plate, an electro-optical switch, a fundamental frequency resonant cavity reflector, a harmonic isolation environment, a frequency doubling crystal and a fundamental frequency/frequency doubling resonant cavity reflector; the pump light emitted by the pump source is focused into the gain medium through the pump coupling element, the polarization beam splitter prism, the fundamental frequency resonant cavity reflector and the fundamental frequency/frequency doubling resonant cavity reflector form an L-shaped folded resonant cavity, the lambda/4 wave plate and the electro-optical switch are arranged on one arm of the folded cavity, and the harmonic isolation environment and the frequency doubling crystal are arranged on the other arm of the resonant cavity.

Preferably, the pump source output mode is spatial light output or fiber coupled output, and the pump mode is pulse pump or continuous pump.

Preferably, the pump coupling element adopts a single lens or a lens group structure to couple the pump light into the laser gain medium with a certain spot size.

Preferably, the resonant cavity of the laser adopts an L-shaped folding cavity structure, the polarization beam splitter prism is used as a folding mirror of the resonant cavity, the polarization beam splitter prism simultaneously plays the roles of a polarizer and the folding mirror of the resonant cavity in the resonant cavity, and the light transmission surface of the polarization beam splitter prism needs to be plated with a pumping light antireflection film at the same time.

Preferably, the laser gain medium is Nd: YVO₄Crystal, Nd: GdVO₄Crystal, Nd: YAG crystal, Nd: YLF crystal, can output 1 μm wavelength laser crystal.

Preferably, the laser gain medium and the lambda/4 wave plate laser electro-optical switch are arranged on one arm of the folding cavity and are used together with the polarization beam splitter prism to realize electro-optical Q-switching; the harmonic separation mirror and the frequency doubling crystal are arranged on the other arm of the resonant cavity, so that the polarization matching of the polarization output of the fundamental frequency light and the frequency doubling of the frequency doubling crystal is realized, and the maximum frequency doubling efficiency is realized.

Preferably, the laser operates in an electro-optical Q-switching mode, which may be a piezo-electric Q-switching mode or a piezo-electric Q-switching mode.

Preferably, the electro-optical switch may be an RTP electro-optical switch, a BBO electro-optical switch, an LGS electro-optical switch, an LN electro-optical switch, or a KD x P electro-optical switch.

Preferably, the frequency doubling mode adopts intracavity frequency doubling, and the phase matching mode of the frequency doubling crystal can be critical phase matching or non-critical phase matching; the output mode of the frequency doubling light is that a harmonic separation mirror is inserted between the polarization beam splitter prism and the frequency doubling crystal, the incident angle of the harmonic separation mirror is 45 degrees or other angles, the passing of the fundamental frequency light can be realized, and the frequency doubling light is output; the frequency doubling crystal is LBO crystal, KTP crystal, PPLN crystal, BBO crystal.

The invention has the beneficial effects that: the invention realizes the output of sub-nanosecond pulse green laser with high frequency doubling efficiency by a short cavity structure, intracavity frequency doubling and electro-optical Q-switching modes, and can be directly used in occasions needing the sub-nanosecond pulse green laser; through the mode of intracavity frequency doubling, realize subnanosecond pulse output, have compact structure, efficient, reliable and stable, advantage such as with low costs.

Drawings

Fig. 1 is a schematic structural diagram of a laser according to the present invention.

Detailed Description

As shown in fig. 1, an electro-optically Q-switched intracavity frequency-doubled subnanosecond pulsed green laser includes: the laser comprises a pumping source, a pumping coupling element, a polarization beam splitter prism, a laser gain medium, a lambda/4 wave plate, an electro-optical switch, a fundamental frequency resonant cavity reflector, a harmonic isolation environment, a frequency doubling crystal and a fundamental frequency/frequency doubling resonant cavity reflector; the pump light emitted by the pump source is focused into the gain medium through the pump coupling element, the polarization beam splitter prism, the fundamental frequency resonant cavity reflector and the fundamental frequency/frequency doubling resonant cavity reflector form an L-shaped folded resonant cavity, the lambda/4 wave plate and the electro-optical switch are arranged on one arm of the folded cavity, and the harmonic isolation environment and the frequency doubling crystal are arranged on the other arm of the resonant cavity.

The laser is a semiconductor laser end-face pumping and pressurizing type electro-optical Q-switch, the resonance adopts a three-mirror folded cavity structure, and subnanosecond pulse green light output can be realized through intra-cavity frequency doubling.

The pumping source 1 is used for generating laser with a certain spectral line width, and is used for pumping the laser gain medium 2, in order to achieve higher conversion efficiency, the output spectral line should match with the absorption spectral line of the laser gain medium 2, the output mode of the pumping source in this embodiment may be a semiconductor laser for spatial light output, or a semiconductor laser for fiber coupling output, and the pumping mode is continuous pumping or pulse pumping.

The pumping coupling element 2 is used for coupling laser generated by the pumping source 1 into the laser gain medium 2 with a specific spot diameter to realize mode matching of the pumping light and oscillation light in resonance, and can be a lens group consisting of a single lens or a plurality of lenses, and an antireflection film for the pumping source 1 is plated on the surface of each lens.

The polarization beam splitter prism 3 mainly plays two roles in resonance, firstly, the polarization beam splitter prism is used as a folding mirror of the resonant cavity to play a role in turning a light path, and secondly, the polarization beam splitter prism is used as a polarizer in the resonant cavity to convert laser generated by the gain medium into linearly polarized light. In this embodiment, the right-angle surface of the polarization beam splitter prism is plated with an antireflection film for pump light and fundamental frequency laser, the inclined surface is plated with an antireflection film for pump light, and the polarization beam splitter prism 3 in this embodiment may also be a polarizer in the form of a dielectric film for fundamental frequency light.

The laser gain medium 4 realizes population inversion after absorbing the pump light of the pump source 1, and can establish laser oscillation as an essential element for generating laser when the gain in the gain medium is larger than the loss of the resonant cavity, wherein the laser gain medium is Nd: YVO₄And (4) crystals.

The lambda/4 wave plate 5 and the electro-optical switch 6 play a role in polarization conversion in the resonant cavity, and Q-switched pulse output is realized. In the embodiment, the laser is a pressurized electro-optical Q-switch, the fast axis direction of the lambda/4 wave plate 5 and the linearly polarized light direction generated by the laser gain medium 4 and the polarization beam splitter prism 3 form an included angle of 45 degrees, and the linearly polarized light is changed into circularly polarized light. When the voltage of lambda/4 is not applied to the electro-optical switch 6, the circularly polarized light is reflected by the base frequency light resonant cavity reflector 7, and then is changed into linearly polarized light after passing through the lambda/4 wave plate 5 again, at the moment, the polarization direction is rotated by 90 degrees, the reflected light is reflected by the polarization splitting prism 3, the resonant cavity can not output laser, and the door closing effect is realized; when lambda/4 wave voltage is applied to the electro-optical switch 6, the resonance realizes the effect of opening the door and outputs a Q-switched pulse. The electro-optical switch 6 in this embodiment is an RTP electro-optical switch.

The fundamental frequency resonator mirror 7 is mainly a mirror for realizing fundamental frequency light, and in this embodiment, the resonator mirror 7 is a 0 ° mirror, and the surface may be a plane, a concave surface, or a convex surface.

The harmonic separation mirror 8 is mainly used for separating the fundamental frequency light from the frequency doubling light, and the frequency doubling light is output out of resonance by plating one surface of the reflector with a coating film for increasing the transmission of the fundamental frequency light and reflecting the frequency doubling light. The incident angle of the harmonic separating mirror in this embodiment is 45 °.

The frequency doubling crystal 9 converts the wavelength of the fundamental light into frequency doubled green light for output mainly by nonlinear frequency conversion, and in this embodiment, the frequency doubling crystal is an LBO crystal.

The fundamental frequency/frequency doubling resonant cavity reflector 10 mainly realizes the simultaneous reflection of fundamental frequency light and frequency doubling light, and through the mode, the double-pass frequency doubling of the fundamental frequency light in the frequency doubling crystal can be realized, and the frequency doubling efficiency is improved. In this embodiment, the fundamental frequency/frequency doubling resonator mirror 10 is a 0 ° mirror, and the surface may be a plane, a concave surface, or a convex surface.