CN116131086A

CN116131086A - Vanadium diselenide saturable absorber film, preparation method thereof and erbium-doped mode-locking pulse fiber laser device

Info

Publication number: CN116131086A
Application number: CN202211711783.5A
Authority: CN
Inventors: 陶丽丽; 黄杰; 谢钊儒; 陈静娴; 招瑜
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-05-16

Abstract

The invention belongs to the technical field of passive mode-locking ultrafast fiber lasers, and discloses a vanadium diselenide saturable absorber film, a preparation method thereof and an erbium-doped mode-locking pulse fiber laser device. Dispersing vanadium diselenide powder in absolute ethyl alcohol, carrying out ultrasonic stripping on the obtained vanadium diselenide alcohol dispersion liquid in an ice-water bath, centrifuging, and taking supernatant after centrifuging; mixing the supernatant, deionized water and PVA water solution uniformly to form a vanadium diselenide dispersion liquid, and vacuum drying the vanadium diselenide dispersion liquid to prepare the vanadium diselenide saturated absorber film. The ultra-short pulse sequence of the vanadium diselenide saturable absorber film is uniform and the performance is stable, and the erbium-doped mode-locked pulse fiber laser device based on the film can generate picosecond ultra-short pulse laser without other operations after the vanadium diselenide saturable absorber film is added into a light path, so that the preparation method is simple, and the industrial production can be realized.

Description

Vanadium diselenide saturable absorber film, preparation method thereof and erbium-doped mode-locking pulse fiber laser device

Technical Field

The invention belongs to the technical field of passive mode-locking ultrafast fiber lasers, and particularly relates to a vanadium diselenide saturable absorber film, a preparation method thereof and an erbium-doped mode-locking pulse fiber laser device.

Background

The fiber laser has the advantages of good beam quality, low cost, high conversion efficiency, good temperature stability, simple structure and the like, so that the fiber laser has important application prospect and research value in the fields of precision machining, surgical medical treatment, communication and the like. An ultrashort pulse fiber laser, also called an ultrafast fiber laser, which is one of the fiber laser branches, has a very narrow pulse width, which can be on the order of picoseconds, femtoseconds, or even attoseconds. The ultra-short pulse width allows ultra-fast fiber lasers to have ultra-high instantaneous power, which can be as high as one hundred billion watts. The pulse generated by the ultrafast laser has the action time with the material, the thermal influence on surrounding materials is avoided, the cut after cutting is smooth, and the damage is small, so that the ultrafast laser cutting cold working has obvious advantages in the field of laser precision machining. In the surgical medical field, femtosecond laser actual force correction, heart stent cutting and the like have been industrialized with ultrafast laser.

At present, technologies for converting continuous fiber laser into pulse laser mainly include a Q-switching technology and a mode locking technology. The Q-switching technology generally changes the Q value in the laser cavity by changing the loss method in the laser cavity so as to generate pulse laser, and the pulse width of the pulse laser obtained by the Q-switching technology is generally of nanosecond or microsecond magnitude. In contrast to pulse lasers produced by Q-switched techniques, which typically produce pulse lasers with pulse widths on the order of picoseconds or femtoseconds, mode-locked techniques produce pulse lasers by loss modulation or self-phase modulation, the most commonly used of which is to obtain pulse laser output by inserting a saturable absorber as an optical modulation device in the laser cavity. The basic principle is that a saturable absorber is added in a light path, the stronger the light source is, the weaker the absorption of the saturable absorber is, when the light source is strong enough, the saturable absorber is bleached and does not absorb light any more, so that light pulses are narrowed, and ultra-short pulse laser is generated. At present, more semiconductor saturable absorber mirrors (SESAMs) are used in mode-locked lasers, but the semiconductor saturable absorber mirrors still have a plurality of problems, for example, in the preparation method, the SESAMs are commonly prepared by a Metal Organic Chemical Vapor Deposition (MOCVD) method or a Molecular Beam Epitaxy (MBE) method, the preparation process is complex, the environmental requirement is high, and the external interference factors are relatively large. Meanwhile, the method has the advantages of narrow working wavelength range (< 100 nm), long recovery time, difficult regulation and control of modulation depth, low photodamage threshold and the like in performance. Therefore, a saturable absorber material capable of overcoming the above defects of the SESAM has been developed as a problem to be solved in the field of ultrashort pulse lasers.

Research on two-dimensional materials makes an important contribution to the development of laser technology, graphene is taken as a novel two-dimensional material, and is widely proven to be capable of generating ultrashort pulse laser as a saturable absorber, but the modulation depth is not more than two percent due to the fact that the nonlinear optical response of a monoatomic layer of graphene is too weak, so that the stability of mode-locked laser is extremely poor. Therefore, it is particularly important to develop a novel saturable absorber material with high stability, high damage threshold and low loss.

Disclosure of Invention

In order to solve the above-mentioned disadvantages and drawbacks of the prior art, a primary object of the present invention is to provide a vanadium diselenide saturable absorber film.

Another object of the present invention is to provide a method for preparing the above-mentioned vanadium diselenide saturable absorber film.

It is still another object of the present invention to provide the erbium-doped mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film as described above.

The aim of the invention is achieved by the following technical scheme:

the vanadium diselenide saturable absorber film is prepared by performing ultrasonic stripping on vanadium diselenide ethanol dispersion liquid in an ice-water bath, performing centrifugal treatment, and taking supernatant after the centrifugal treatment to obtain vanadium diselenide ethanol supernatant; mixing the vanadium diselenide ethanol supernatant, deionized water and PVA water solution uniformly to form a vanadium diselenide dispersion liquid, and carrying out vacuum drying to obtain the vanadium diselenide.

Preferably, the volume ratio of the vanadium diselenide ethanol supernatant to the deionized water to the PVA aqueous solution is 1:1 (2-4).

Preferably, the concentration of the PVA aqueous solution is 4 to 10% by weight.

The preparation method of the vanadium diselenide saturable absorber film comprises the following specific steps:

s1, dispersing vanadium diselenide powder in absolute ethyl alcohol, carrying out ultrasonic stripping on the obtained vanadium diselenide ethanol dispersion liquid in an ice-water bath, centrifuging, and taking supernatant after centrifuging to obtain vanadium diselenide ethanol supernatant;

s2, uniformly mixing the vanadium diselenide ethanol supernatant, deionized water and PVA aqueous solution to form vanadium diselenide dispersion liquid, and carrying out vacuum drying to obtain the vanadium diselenide saturable absorber film.

Preferably, the volume ratio of the mass of the vanadium diselenide powder to the absolute ethanol in the step S1 is (1-2) mg/200 mL.

Preferably, the time of the ultrasonic treatment in the step S1 is 24-48 hours, the rotating speed of the centrifugation is 3000-5000 rpm, and the time of the centrifugation is 3-5 minutes.

Preferably, the temperature of the vacuum drying in the step S2 is 40-80 ℃, and the time of the vacuum drying is 20-60 hours.

The erbium-doped mode-locking pulse fiber laser device comprises a laser pumping source, a wavelength division multiplexer, a gain fiber, a polarization independent isolator, an output coupler, a first single mode fiber, a vanadium diselenide saturable absorber film, a second single mode fiber and a polarization controller which are sequentially connected.

Further, the wavelength division multiplexer includes a first input terminal and a second input terminal; the output coupler comprises a 90% output end and a 10% output end; the vanadium diselenide saturable absorber film is transferred to the end face of the optical fiber cone region, the other end of the film is connected by a flange plate and is arranged in the optical fiber flange, and the two ends of the film are respectively connected with the second input end of the wavelength division multiplexer and the polarization controller by single-mode fibers; the laser pumping source, the first input end of the wavelength division multiplexer, the gain fiber, the polarization independent isolator, the 90% output end of the output coupler, the first single mode fiber and the vanadium diselenide saturable absorber film are transferred to the end face of the cone region, and the second single mode fiber and the polarization controller are sequentially connected to form the annular resonant cavity.

Preferably, the gain fiber is erbium-doped fiber with length of 1-1.2 m, wavelength of the laser pumping source is 975-980 nm, and center wavelength of the wavelength division multiplexer is 1550-1800 nm.

Compared with the prior art, the invention has the following beneficial effects:

1. the vanadium diselenide saturable absorber film prepared by the invention is a broadband saturable absorber, has large modulation depth, is easy to realize mode locking, and generates ultrashort pulse laser.

2. The erbium-doped mode-locking pulse fiber laser device based on the vanadium diselenide saturable absorber film only needs to transfer the vanadium diselenide film to the end face of the fiber connector, is convenient to operate, and the whole laser path system runs in the fiber, is not interfered by external environment, and has very stable laser performance.

Drawings

Fig. 1 is a schematic diagram of an erbium-doped mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film of application example 1.

Fig. 2 is a graph of pulse sequences of different dimensions obtained by the erbium-doped mode-locked pulse fiber laser device based on the vanadium diselenide saturable absorber film of application example 1 at a pumping rate of 160 mW.

FIG. 3 is a spectrum obtained at a pumping rate of 160mw for a mode-locked pulsed fiber laser device based on a vanadium diselenide saturable absorber film of application example 1.

Fig. 4 is a graph of the autocorrelation trace and fit obtained by the erbium-doped mode-locked pulse fiber laser apparatus of application example 1 based on a vanadium diselenide saturable absorber film at a pumping rate of 160 mW.

Fig. 5 is a radio frequency plot obtained for the erbium-doped mode-locked pulsed fiber laser device of application example 1 based on a vanadium diselenide saturable absorber film at a pumping rate of 160 mW.

Detailed Description

The present invention is further illustrated below in conjunction with specific examples, but should not be construed as limiting the invention. The technical means used in the examples are conventional means well known to those skilled in the art unless otherwise indicated. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art.

Example 1

5mg of vanadium diselenide powder was mixed with 20mL of ethanol to form a vanadium diselenide ethanol dispersion. And (3) placing the vanadium diselenide ethanol dispersion liquid in an ultrasonic cleaning machine for ultrasonic stripping for 24 hours, placing the ultrasonic stripped vanadium diselenide ethanol dispersion liquid in a centrifugal machine, and carrying out centrifugal treatment on the ultrasonic stripped vanadium diselenide ethanol dispersion liquid, wherein the centrifugal speed is 5000rpm, and the time is 5min. Taking supernatant of the centrifuged vanadium diselenide ethanol dispersion liquid, deionized water and 4% wtPVA aqueous solution, uniformly mixing to form the vanadium diselenide dispersion liquid, transferring the vanadium diselenide dispersion liquid into a culture dish, placing the culture dish in a vacuum drying oven, drying at 40-80 ℃ for 20-60 h to obtain a vanadium diselenide saturated absorber film, cutting into 2X 2mm small pieces, and transferring the small pieces to the end face of an optical fiber cone.

Example 2

10mg of vanadium diselenide powder was mixed with 50mL of ethanol to form a vanadium diselenide ethanol dispersion. And (3) placing the vanadium diselenide ethanol dispersion liquid in an ultrasonic cleaning machine for ultrasonic stripping for 48 hours, placing the ultrasonic stripped vanadium diselenide ethanol dispersion liquid in a centrifugal machine, and carrying out centrifugal treatment on the ultrasonic stripped vanadium diselenide ethanol dispersion liquid, wherein the centrifugal speed is 4000rpm, and the time is 8min. Taking supernatant of the centrifuged vanadium diselenide ethanol dispersion liquid, deionized water and 6% wtPVA aqueous solution, uniformly mixing to form the vanadium diselenide dispersion liquid, transferring the vanadium diselenide dispersion liquid into a culture dish, placing the culture dish in a vacuum drying oven, drying at 40-80 ℃ for 20-60 h to obtain a vanadium diselenide saturated absorber film, cutting into 2X 2mm small pieces, and transferring the small pieces to the end face of an optical fiber cone.

Example 3

15mg of vanadium diselenide powder was mixed with 65mL of ethanol to form a vanadium diselenide ethanol dispersion. And (3) placing the vanadium diselenide ethanol dispersion liquid in an ultrasonic cleaning machine for ultrasonic stripping for 72 hours, placing the ultrasonic stripped vanadium diselenide ethanol dispersion liquid in a centrifugal machine, and carrying out centrifugal treatment on the ultrasonic stripped vanadium diselenide ethanol dispersion liquid, wherein the centrifugal speed is 10000rpm, and the time is 3min. Taking supernatant of the centrifuged vanadium diselenide ethanol dispersion liquid, deionized water and 8% wtPVA aqueous solution, uniformly mixing to form the vanadium diselenide dispersion liquid, transferring the vanadium diselenide dispersion liquid into a culture dish, placing the culture dish in a vacuum drying oven, drying at 40-80 ℃ for 20-64 h to obtain a saturated absorber film based on vanadium diselenide, cutting into 2X 2mm small pieces, and transferring the small pieces to the end face of an optical fiber cone.

Application example 1

Fig. 1 is a schematic diagram of an erbium-doped mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film in application example 1. Wherein, 1 is a laser pumping source, 2 is a wavelength division multiplexer, 21 is a first input end of the wavelength division multiplexer, and 22 is a second input end of the wavelength division multiplexer 2; 3 is a gain fiber, 4 is a polarization independent isolator, 5 is an output coupler, 51 is a first input end of the output coupler, and 52 is a second input end of the output coupler; 7 is a first single mode fiber, 6 is a vanadium diselenide saturable absorber film, 9 is a second single mode fiber, and 8 is a polarization controller. The erbium-doped mode-locked pulse fiber laser device in the application example adopts an annular cavity structure, the erbium-doped fiber is selected as the gain fiber 3, the wavelength of the laser pumping source 1 is 975-980 nm, and the central wavelength of the wavelength division multiplexer 2 is 1550-1800 nm. The output coupler 5 includes 90

% output

51 and 10% output 52; the laser pumping source 1, the first input end 21 of the wavelength division multiplexer 2, the gain optical fiber 3, the polarization independent isolator 4, the 90% output end 51 of the output coupler 5, the first single mode fiber 7, the vanadium diselenide saturable absorber film 6, the second single mode fiber 9 and the polarization controller 8 are sequentially connected by an optical fiber fusion splicer according to the sequence of fig. 1, and the vanadium diselenide saturable absorber film 6 of the embodiment 1 is connected with the output coupler 5 to form a ring-shaped resonant cavity; the vanadium diselenide saturable absorber film 6 is transferred to the end face of an optical fiber jumper, is connected with another optical fiber jumper by a flange plate, is arranged in the optical fiber flange, and is respectively connected with the second end 52 of the output coupler 5 and the polarization controller 8 by a first single-mode optical fiber 7 and a second single-mode optical fiber 9 at two ends. An autocorrelation instrument, a spectrometer, and an oscilloscope are connected to the 10% output 51 of the output coupler 5 to measure the laser output characteristics of the fiber laser.

Fig. 2 is a pulse sequence diagram of an erbium-doped mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film in application example 1. Wherein, (a) is a pulse sequence at a scanning speed of 100ns/div, and (b) is a pulse sequence at a scanning speed of 40 ns/div. From fig. 2, it can be seen that the mode locking pulse operation in the annular chamber is performed in a relatively stable state when the scanning speed of the oscilloscope is 200 ns/div. When the scanning speed of the oscilloscope is slowed down to 40ns/div, the pulse interval can be accurately measured to be 43.32ns. Therefore, the erbium-doped mode-locked pulse fiber laser device based on the vanadium diselenide saturable absorber film can output pulses with good stability. FIG. 3 is a graph showing the output spectrum of the mode-locked pulse fiber laser device based on the vanadium diselenide saturable absorber film of application example 1. As can be seen from fig. 3, the laser center wavelength in the annular cavity was 1564.42nm and the spectral width was 2.92nm. Fig. 4 is a pulse width diagram of a mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film in application example 1, and as can be seen from fig. 4, the pulse width of the pulse laser is 1.02ps. Fig. 5 is a signal-to-noise ratio diagram of a mode-locked pulse fiber laser device based on a vanadium diselenide saturable absorber film of application example 1, wherein (a) is a pulse sequence diagram at a scanning speed of 100ns/div, and (b) is a pulse sequence diagram at a scanning speed of 40 ns/div. As can be seen from fig. 5, the signal-to-noise ratio intensity of the laser device remains relatively stable in the range of 0z to 1GHz, with a signal-to-noise ratio of the laser device up to 51.6dB at the fundamental frequency.

The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims

1. The vanadium diselenide saturable absorber film is characterized in that vanadium diselenide ethanol dispersion liquid is subjected to ultrasonic stripping in an ice-water bath, and after centrifugal treatment, supernatant fluid after the centrifugal treatment is taken to obtain vanadium diselenide ethanol supernatant fluid; mixing the vanadium diselenide ethanol supernatant, deionized water and PVA water solution uniformly to form a vanadium diselenide dispersion liquid, and carrying out vacuum drying to obtain the vanadium diselenide.

2. The vanadium diselenide saturable absorber film of claim 1, wherein the volume ratio of vanadium diselenide ethanol supernatant, deionized water, and PVA aqueous solution is 1:1 (2-4).

3. The vanadium diselenide saturable absorber film of claim 1, wherein the PVA aqueous solution has a concentration of 4 to 10wt%.

4. A method for preparing a vanadium diselenide saturable absorber film as set forth in any one of claims 1-3, comprising the specific steps of:

5. The method of producing a vanadium diselenide saturable absorber film according to claim 4, wherein the ratio of the mass of the vanadium diselenide powder to the volume of absolute ethanol in step S1 is (1-2) mg/200 mL.

6. The method for producing a vanadium diselenide saturable absorber film as set forth in claim 4, wherein the time of the ultrasonic treatment in step S1 is 24 to 48 hours, the rotational speed of the centrifugation is 3000 to 5000rpm, and the time of the centrifugation is 3 to 5 minutes.

7. The method for producing a vanadium diselenide saturable absorber film as set forth in claim 4, wherein the vacuum drying temperature in step S2 is 40 to 80 ℃ and the vacuum drying time is 20 to 60 hours.

8. An erbium-doped mode-locked pulse fiber laser device, which is characterized by comprising a laser pumping source, a wavelength division multiplexer, a gain fiber, a polarization independent isolator, an output coupler, a first single-mode fiber, the vanadium diselenide saturable absorber film according to any one of claims 1-3, a second single-mode fiber and a polarization controller which are connected in sequence.

9. The erbium-doped mode-locked pulse fiber laser device of claim 8, wherein the wavelength division multiplexer comprises a first input and a second input; the output coupler comprises a 90% output end and a 10% output end; the vanadium diselenide saturable absorber film is transferred to the end face of the optical fiber cone region, the other end of the film is connected by a flange plate and is arranged in the optical fiber flange, and the two ends of the film are respectively connected with the second input end of the wavelength division multiplexer and the polarization controller by single-mode fibers; the laser pumping source, the first input end of the wavelength division multiplexer, the gain fiber, the polarization independent isolator, the 90% output end of the output coupler, the first single mode fiber and the vanadium diselenide saturable absorber film are transferred to the end face of the cone region, and the second single mode fiber and the polarization controller are sequentially connected to form the annular resonant cavity.

10. An erbium-doped mode-locked pulse fiber laser device according to claim 8 or 9, wherein the gain fiber is an erbium-doped fiber having a length of 1 to 1.2m, the wavelength of the laser pumping source is 975 to 980nm, and the center wavelength of the wavelength division multiplexer is 1550 to 1800nm.