CN213584589U

CN213584589U - Q-switched pulse laser based on vanadium dioxide film saturable absorber

Info

Publication number: CN213584589U
Application number: CN202022808304.4U
Authority: CN
Inventors: 常建华; 孟园园; 周妹; 陈思成; 刘海洋; 杨镇博
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Ideal Technology Development Beijing Co ltd
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2021-06-29
Anticipated expiration: 2030-11-27

Abstract

The utility model discloses a transfer Q pulse laser based on but vanadium dioxide film saturable absorber belongs to pulse laser technical field and nonlinear optics field. The main device of the laser comprises a semiconductor Laser (LD), a coupling lens group, Nd, YCOB crystal, a planoconcave mirror, a reflector, a vanadium dioxide film saturable absorber and a PPLN crystal. The concave surface of the first plano-concave mirror is opposite to the concave surface of the second plano-concave mirror, the reflecting surface of the reflecting mirror faces the concave surface of the second plano-concave mirror and the input end of the vanadium dioxide film saturable absorber, and the output end of the vanadium dioxide film saturable absorber faces the PPLN crystal and is arranged in parallel with the PPLN crystal. The utility model provides a transfer Q pulse laser based on but vanadium dioxide film saturable absorber utilizes the saturable absorption characteristic of saturable absorber vanadium dioxide film, changes laser resonator's quality to make this laser instrument can obtain the pulse laser output of continuous stability, realize the pulse output of picosecond level.

Description

Q-switched pulse laser based on vanadium dioxide film saturable absorber

Technical Field

The utility model relates to a pulse laser technical field and nonlinear optics field especially relate to a transfer Q pulse laser based on but vanadium dioxide film saturable absorber.

Background

The pulse laser with the pulse width less than 1ns has the capability of transferring energy to a target in a short time, and the thermal diffusion effect of the energy in a material is weak, so that the pulse laser can be applied to clinical medicine. For example, focused picosecond pulses can remove tattoos. Typically, picosecond lasers can be produced by mode-locked or Q-switched processes. In a waveguide laser system, compared with mode-locked picosecond laser, laser obtained by Q modulation has higher peak power and wider application range. The scheme provides a saturable absorber vanadium dioxide (VO) with a low saturable absorption threshold₂)，VO₂The material is a phase-change material, and the electrical and optical properties of the material are uniquely changed in the phase-change process, so that the material has certain application value in the fields of electronics, intelligent optics, photoelectronics, photonics and the like.

The existing picosecond laser systems are mostly solid lasers and fiber lasers, and compared with the two types of lasers, the optical waveguide lasers which are grown in recent years have many advantages: the size is smaller, the structure is more compact, and the device is convenient to integrate with other devices on the same chip; the optical waveguide structure is used as a laser resonant cavity, so that low laser threshold and high slope efficiency can be realized under low-energy pumping, and an efficient laser system is convenient to construct; with shorter resonator lengths (typically in millimeters), the cavity round-trip time is typically less than 1 ns. Thus, in principle, picosecond laser pulses can be generated within the optical waveguide by Q-switching. However, the output power of optical waveguide lasers is relatively low and it is often difficult to reach the saturation absorption threshold of saturable absorbers. To date, there has been no report of picosecond waveguide lasers implemented by Q-switched technology using saturable absorbers (e.g., graphene, carbon nanotubes, etc.). The proper selection of a saturable absorber with a low saturable absorption threshold to modulate an optical waveguide laser is key to the realization of picosecond optical waveguide lasers.

And VO₂The time for the thin film material to be converted between the insulating phase and the metal phase is short and is only in the order of subpicosecond, so that the new function can be realized by utilizing the difference of physical properties of different phases of the thin film material. For example, VO₂The film material is reverse saturable absorption material in both insulating phase and metal phase, but metal phase VO₂The light absorption intensity of the film is far lower than that of the insulating phase VO₂Light absorption intensity of the film. VO due to the difference of light absorption intensity between the two phases during the transition from the insulating phase to the metal phase₂Thin film materials may exhibit saturable absorption phenomena.

Disclosure of Invention

To the above problem, the utility model provides a transfer Q pulse laser based on but vanadium dioxide film saturable absorber.

In order to realize the utility model discloses an aim at, provide a transfer Q pulse laser based on but vanadium dioxide film saturable absorber, include: the device comprises a semiconductor laser, a coupling lens group, Nd, YCOB crystal, a first plano-concave mirror, a second plano-concave mirror, a plane reflector, a vanadium dioxide film saturable absorber and PPLN crystal.

And continuous light emitted by the semiconductor laser is incident to the Nd: YCOB crystal through the coupling lens group, the Nd: YCOB crystal gains the central wavelength of the continuous light, the gained continuous light is firstly reflected to the second plano-concave mirror through the first plano-concave mirror, then is secondly reflected to the plane reflecting mirror through the second plano-concave mirror, is thirdly reflected to the vanadium dioxide film saturable absorber through the plane reflecting mirror, passes through the vanadium dioxide film saturable absorber to reach the PPLN crystal, and is output from the PPLN crystal.

Further, the center wavelength of continuous light emitted by the semiconductor laser is 808 nm; the center wavelength of the continuous light after gaining through the Nd: YCOB crystal is 1064 nm.

Furthermore, one surface of the Nd: YCOB crystal close to the coupling lens group is plated with an antireflection film of 808nm and a high reflection film of 1064nm, and one surface of the Nd: YCOB crystal far away from the coupling lens group is plated with an antireflection film of 1064 nm.

Further, the concave surface of the first plano-concave mirror is plated with a 1064nm high-reflection film.

Further, the concave mirror of the second plano-concave mirror is plated with a 1064nm high-reflection film.

Further, a 1064nm high-reflection film is plated on one surface, facing the vanadium dioxide saturable absorber, of the plane mirror.

Compared with the prior art, the utility model discloses following beneficial technological effect has:

VO₂the time for the (vanadium dioxide) film material to be converted between the insulating phase and the metal phase is short and is only in the order of subpicosecond, so that the novel function can be realized by utilizing the difference of the physical properties of different phases of the (vanadium dioxide) film material. VO (vacuum vapor volume)₂The preparation process has less pollution and low cost, and is favorable for environmental protection and energy saving. VO (vacuum vapor volume)₂The thin film has the characteristic of thermal hysteresis capable of being saturated and absorbed, and the composite waveguide can generate continuous laser and picosecond pulse laser under the same temperature condition through cooling or heating treatment, so that the composite waveguide is widely applied to a plurality of fields.

Drawings

FIG. 1 is a schematic structural diagram of a Q-switched pulse laser based on a vanadium dioxide thin film saturable absorber according to an embodiment.

Description of reference numerals: the optical fiber laser comprises a 1-semiconductor laser, a 2-coupling lens group, a 3-Nd YCOB crystal, a 4-first plano-concave mirror, a 5-second plano-concave mirror, a 6-plane mirror, a 7-vanadium dioxide saturable absorber and an 8-PPLN crystal.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

As shown in figure 1, the VO of the utility model₂The film saturable absorber is used as a Q-switched pulse laser device, the concave surface of the first plano-concave mirror 4 is opposite to the concave surface of the second plano-concave mirror 5, and the reflecting surface of the plane reflecting mirror 6 faces the concave surface of the second plano-concave mirror 5 and the VO₂Input terminal, VO, of a thin film saturable absorber 7₂The output end of the film saturable absorber 7 faces the PPLN crystal 8, VO₂A thin film saturable absorber 7 is disposed in parallel with the PPLN crystal 8.

The utility model discloses optical parametric oscillator's theory of operation is: the semiconductor laser 1 generates 808nm continuous light to be emitted to the coupling lens group 2, the 808nm continuous light is output by the Nd-YCOB crystal 3 to be 1064nm continuous light, the continuous light is emitted to the second plano-concave mirror 5 after the first reflection of the first plano-concave mirror 4, the second plano-concave mirror 5 reflects again to be emitted to the plane reflector 6, the continuous light is emitted to VO after the third reflection of the plane reflector 6₂Thin film saturable absorber 7, into VO₂The thin film saturable absorber 7 passes through the PPLN crystal 8, and Q-switched pulse laser with the wavelength of 1064nm is output by the PPLN crystal 8.

The saturable absorber has the working principle that: the absorption of the saturable absorber material to the laser in the cavity can change along with the intensity of the optical field, when the light intensity is weaker, the light absorption is strong, the loss in the cavity is increased, and therefore the light transmittance is very low. VO with increasing light intensity₂The film has reduced absorption of light and reduced intra-cavity loss when the light intensity exceeds a certain valueThe absorption is saturated when the value is reached, the light transmittance can reach 100 percent, the light intensity is subjected to minimum loss while the maximum laser pulse is obtained, and the strong pulse laser is output.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

It should be noted that the terms "first \ second \ third" referred to in the embodiments of the present application merely distinguish similar objects, and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may exchange a specific order or sequence when allowed. It should be understood that "first \ second \ third" distinct objects may be interchanged under appropriate circumstances such that the embodiments of the application described herein may be implemented in an order other than those illustrated or described herein.

The terms "comprising" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device that comprises a list of steps or modules is not limited to the listed steps or modules but may alternatively include other steps or modules not listed or inherent to such process, method, product, or device.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A Q-switched pulse laser based on a vanadium dioxide thin film saturable absorber is characterized by comprising: the device comprises a semiconductor laser (1), a coupling lens group (2), a Nd, YCOB crystal (3), a first plano-concave mirror (4), a second plano-concave mirror (5), a plane mirror (6), a vanadium dioxide film saturable absorber (7) and a PPLN crystal (8);

continuous light emitted by the semiconductor laser (1) enters the Nd-YCOB crystal (3) through the coupling lens group (2), the Nd-YCOB crystal (3) gains the central wavelength of the continuous light, the gained continuous light is firstly reflected to the second concave mirror (5) through the first concave mirror (4), then is secondly reflected to the plane mirror (6) through the second concave mirror (5), is thirdly reflected to the vanadium dioxide film saturable absorber (7) through the plane mirror (6), passes through the vanadium dioxide film saturable absorber (7), reaches the LN PPCrystal (8), and is output from the PPLN crystal (8).

2. The vanadium dioxide thin film saturable absorber-based Q-switched pulsed laser according to claim 1, wherein the semiconductor laser (1) emits continuous light with a center wavelength of 808 nm; the center wavelength of the continuous light after the gain of the Nd: YCOB crystal (3) is 1064 nm.

3. The Q-switched pulse laser based on the vanadium dioxide thin film saturable absorber is characterized in that one surface of the Nd: YCOB crystal (3) close to the coupling lens group (2) is plated with an antireflection film of 808nm and a high-reflection film of 1064nm, and one surface of the Nd: YCOB crystal (3) far from the coupling lens group (2) is plated with an antireflection film of 1064 nm.

4. The Q-switched pulsed laser based on a vanadium dioxide thin film saturable absorber as claimed in claim 1, wherein the concave surface of the first plano-concave mirror (4) is coated with a 1064nm high reflective film.

5. The Q-switched pulsed laser based on a vanadium dioxide thin film saturable absorber as claimed in claim 1, characterized in that the concave mirror of the second plano-concave mirror (5) is coated with a 1064nm high-reflection film.

6. The Q-switched pulsed laser based on the vanadium dioxide thin film saturable absorber (GJH) as claimed in claim 1, wherein the side of the plane mirror (6) facing the vanadium dioxide thin film saturable absorber (7) is coated with a 1064nm high reflection film.