CN113210873B - A kind of preparation method of metal nanomesh based on electronic dynamic regulation - Google Patents

Abstract

The invention relates to a preparation method of a metal nano-mesh based on electronic dynamic regulation, and belongs to the technical field of laser application. The present invention is based on the idea of electronic dynamic regulation, and uses the polarization directions perpendicular to each other, the pulse delay is in the range of 4ps-9ps, and the total energy density of the double pulse is in the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed. Second laser double pulse sequence for direct writing processing, under suitable scanning parameters, the metal nano-network structure can be obtained. Compared with the traditional processing method, the present invention does not need a mask, a template, etc., the process is simple, and the cost is low.

Description

A kind of preparation method of metal nanomesh based on electronic dynamic regulation

technical field

The invention relates to a preparation method of a metal nano-mesh based on electronic dynamic regulation, and belongs to the technical field of laser application.

Background technique

The metal nano-network structure is a micro-nano structure with a size scale in the nanometer scale, and its structure size is between ten nanometers to several tens of nanometers. With the rapid development of micro-nano technology, the preparation of metal nano-networks has received extensive attention due to its great application prospects in the fields of wettability, surface-enhanced Raman scattering, structural color surfaces, and solar cells. At present, the methods for preparing metal nano-networks include template-assisted method, vapor-liquid-solid direct growth method, photolithography, and thin film deposition method. However, these methods often require complicated process flow, expensive equipment and harsh processing environment, which makes the preparation cost of metal nano-networks relatively high.

In recent years, femtosecond laser direct writing technology has gradually played an important role in the fabrication of metal micro-nano structures due to its ability to realize nano-scale processing, flexible 3D processing, and the ability to process almost any material.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing a metal nano-mesh structure by using a femtosecond laser based on electronic dynamic regulation. A femtosecond laser double-pulse sequence in the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed produces a metal nano-network structure on the metal surface.

In order to realize the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A preparation method of a metal nano-network structure based on electronic dynamic regulation, comprising the following steps:

Step 1: The femtosecond laser single pulse is transformed into a femtosecond laser double pulse sequence with the polarization directions perpendicular to each other through the combined optical path of the Michelson interferometer and the quarter-wave plate, and then the energy of the two sub-pulses of the femtosecond laser double pulse is adjusted to be equal , at the same time, the total energy density of the double pulse is adjusted to the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed; in the range of 9ps.

Step 2: The femtosecond laser double-pulse sequence obtained in step 1 is vertically focused on the surface of the metal material to be processed through an optical lens, and the metal material to be processed is controlled to move at a set moving speed, and the metal nano-mesh can be obtained on the metal surface. like structure.

Further, in the process of generating the femtosecond laser double pulse sequence with the polarization directions perpendicular to each other in step 1, the included angle between the optical axis of the quarter-wave plate and the polarization direction of the laser light is 45°.

In step 2, when the used focusing lens is a plano-convex lens with a focal length of 100 mm, the laser repetition frequency is 1000 Hz, and the moving speed of the metal material to be processed is 200-500 μm/s.

The device for implementing the above method includes: a femtosecond laser, a first reflector, a second reflector, a first attenuator, a third reflector, a one-dimensional translation stage, a beam splitter, a second attenuator, a quarter After the wave plate, the fourth mirror, the fifth mirror, the optical shutter, the sixth mirror, the seventh mirror, and the eighth mirror, the polarization directions are perpendicular to each other, and the femtosecond pulse delay is in the range of 4ps-10ps. The laser double-pulse sequence, after being focused by a lens, scans and processes the surface of the metal material to be processed to prepare a metal nano-mesh.

Beneficial effects:

The present invention is based on the idea of electronic dynamic regulation, and uses the polarization directions perpendicular to each other, the pulse delay is in the range of 4ps-9ps, and the total energy density of the double pulse is in the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed. Second laser double pulse sequence for direct writing processing, under suitable scanning parameters, the metal nano-network structure can be obtained. Compared with the traditional processing method, the present invention does not need a mask, a template, etc., the process is simple, and the cost is low.

Description of drawings

FIG. 1 is an optical path diagram of the processing method of the present invention.

2 is a SEM image of the metal nano-network structure processed on the surface of a metal titanium material with a pulse delay of 4 ps according to Embodiment 1 of the present invention, (a) is the image under low magnification, (b) is the image under high magnification Enlarge the image.

3 is a SEM image of the metal nano-mesh structure processed on the surface of the metal titanium material with a pulse delay of 5ps according to Embodiment 2 of the present invention

4 is a SEM image of the metal nano-mesh structure processed on the surface of the metal titanium material with a pulse delay of 6ps according to Embodiment 3 of the present invention

Fig. 5 is the SEM image of the metal nano-mesh structure processed on the surface of the metal titanium material with the pulse delay of 8ps according to the embodiment 4 of the present invention

FIG. 6 is a SEM image of the metal nano-network structure processed on the surface of the metal titanium material with a pulse delay of 9 ps according to Embodiment 5 of the present invention

FIG. 7 is a SEM image of the metal nanostructure processed on the surface of the metal titanium material with a pulse delay of 10ps according to Embodiment 6 of the present invention

Among them, 1-femtosecond laser, 2-first reflector, 3-second reflector, 4-first attenuator, 5-third reflector, 6-one-dimensional translation stage, 7-beam splitter, 8- -2nd attenuation plate, 9-quarter wave plate, 10-fourth mirror, 11-fifth mirror, 12-light shutter, 13-sixth mirror, 14-seventh mirror, 15- Eighth reflection mirror, 16-focusing lens, 17-metal material to be processed, 18-three-dimensional translation stage.

Detailed ways

The following geometric figures and embodiments further illustrate the content of the present invention.

Example 1:

A preparation method of a metal nanomesh based on electronic dynamic regulation, the specific steps are as follows:

Step (1) Using a femtosecond laser 1 to generate a single pulse of a femtosecond laser with a repetition frequency of 1000 Hz and a wavelength of 800 nm horizontally polarized, it enters the optical path of the Michelson interferometer structure through the first mirror 2 and the second mirror 3. Rotate the angle of the quarter-wave plate 9 to 0°. At this time, the two sub-pulses of the double pulse generated by the Michelson interferometer are both horizontally polarized. A fluorescent plate is placed in front of the exit of the Michelson interferometer to observe the two sub-pulses. For the light spot after the spatial overlap of the pulses, adjust the one-dimensional translation stage 6 to adjust the time delay of the two sub-pulses. When it is observed that the light spot after the spatial overlap of the two sub-pulses starts to flicker continuously on the phosphor plate, adjust to the position where the light spot flickers the most. The delay between the two sub-pulses is zero. Then, the angle of the quarter-wave plate 9 is rotated to 45°, and at this time, the polarization direction of the sub-pulses of the transmission arm of the Michelson interferometer is changed from horizontal polarization to vertical polarization. Then, the first attenuator 4 and the second attenuator 8 are adjusted to make the energy of the two sub-pulses equal, both being 0.325 μJ. Next, adjust the one-dimensional translation stage 6 to move 600 μm on the basis of the previous delay zero point, so that the difference between the two sub-pulses is 1200 μm, and the delay time of the two sub-pulses is 4 ps. At this time, through step (1), a femtosecond laser double-pulse sequence with mutually perpendicular polarization directions, equal sub-pulse energies, and pulse delay of 4ps is obtained.

Step (2) The femtosecond laser double pulse sequence obtained in step (1) reaches the focusing lens 16 via the fifth mirror 11, the optical shutter 12, the sixth mirror 13, the seventh mirror 14 and the eighth mirror 15 , and focus on the surface of the metal material 17 to be processed through the focusing lens 16. In this embodiment, the metal material to be processed is titanium metal. In this embodiment, the focusing lens is a plano-convex lens with a focal length of 100 mm, and the beam diameter before the beam reaches the focusing lens is 4 mm. After focusing, the beam waist diameter is about 38μm, the total energy of the femtosecond laser double pulse is 0.65μJ, and the energy density after focusing is 0.117J/cm^2, which is less than the ablation threshold of metal titanium material 0.119J/cm^2. Open the light shutter 12 and control the three-dimensional translation stage 18 to move at a speed of 350 μm/s, and then the metal nano-mesh structure as shown in FIG. 2 can be prepared.

As shown in FIG. 2, it is the SEM image of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention, (a) is the image under low magnification, (b) is the magnification under high magnification picture. The diameter of the nanomesh is mostly between 50nm and 100nm by measurement.

As shown in Figure 1, the device for realizing the above method is as follows:

The second laser 1 used in the present invention is a laser produced by Spectrum Physics, a company in the United States, with a laser center wavelength of 800 nm, a pulse width of 50 fs, a maximum repetition frequency of 1000 Hz, a maximum energy of 3 mJ for single-side punching, a Gaussian light intensity distribution, and an export laser. for horizontal linear polarization.

The metal material used in this embodiment is metal titanium, and the present invention is not limited to metal titanium materials, and other metal materials are acceptable.

The present invention uses the first attenuating sheet 4 and the second attenuating sheet 8 to adjust the energy of the two sub-pulses of the double pulse, and the present invention requires the two sub-pulses to be equal in energy. In this embodiment, the total energy density of the femtosecond laser double pulse sequence used is 0.117J/cm^2, and the total energy density required by the present invention needs to be strictly smaller than the ablation threshold of the metal material and cannot be too small. When the total energy density is greater than or equal to the ablation threshold of the metal material, other subwavelength structures will be generated, which will destroy the prepared metal nanomesh structure; when the total energy density used is much smaller than the ablation threshold of the metal material, it will not Micro-nano structures are obtained by processing the surface of metal materials. The present invention is not limited to the above-mentioned energy density, as long as the total energy density is in the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed.

In this embodiment, the focusing lens is a plano-convex lens with a focal length of 100 mm, which is used to focus the femtosecond laser double-pulse sequence beam onto the surface of the metal material to be processed. The present invention is not limited to the focusing lens being a plano-convex lens with a focal length of 100 mm, a convex lens with other focal lengths or a processed objective lens can be used.

The present invention uses a three-dimensional translation stage 18 to control the motion of the metal material to be processed. In this embodiment, a plano-convex lens with a focal length of 100 mm is used, and the movement speed of the metal material is 350 μm/s. The present invention is not limited to this moving speed, it only needs to be able to process metal nano-mesh on the surface of the material under other suitable processing parameters, and the moving speed of the metal material to be processed can be in the range of 200-500 μm/s.

Example 2:

Other steps are the same as in Embodiment 1, except that the delay time of the two sub-pulses in step (1) is 5ps.

The metal nano-network structure shown in Figure 3 was prepared.

As shown in FIG. 3 , it is an SEM image under high magnification of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention. The diameter of the nanomesh is mostly between 60nm and 150nm by measurement.

Example 3:

Other steps are the same as those in Embodiment 1, except that the delay time of the two sub-pulses in step (1) is 6ps.

The metal nano-network structure shown in Figure 4 was prepared.

As shown in FIG. 4 , it is an SEM image under high magnification of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention. The diameter of the nanomesh is mostly between 80nm and 150nm by measurement.

Example 4:

The other steps are the same as in Embodiment 1, except that the delay time of the two sub-pulses in step (1) is 8ps.

The metal nano-network structure shown in Figure 5 was prepared.

As shown in FIG. 5 , it is an SEM image under high magnification of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention. The nano-mesh structure produced at this time is no longer the nano-mesh with relatively uniform length and width in Examples 1-3, but the nano-mesh in the shape of a long strip. After measurement, most of the short diameters of the nanomesh are between 100nm and 200nm, and most of the long diameters are between 300nm and 450nm.

Example 5:

Other steps are the same as in Embodiment 1, except that the delay time of the two sub-pulses in step (1) is 9ps. The metal nano-network structure shown in Figure 6 was prepared.

As shown in FIG. 6 , it is an SEM image under high magnification of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention. The nano-mesh structure produced at this time is no longer the nano-mesh with relatively consistent length and width in Examples 1-3, but the nano-mesh in the shape of a long strip. After measurement, the short diameter of the nano-mesh is mostly 100 nm. Between 200nm, the major diameter is mostly between 300nm and 500nm.

Example 6:

Other steps are the same as those in Embodiment 1, except that the delay time of the two sub-pulses in step (1) is 10ps. The metal nanostructure shown in Figure 7 was prepared.

As shown in FIG. 7 , it is an SEM image under high magnification of the metal nano-network structure processed on the surface of the metal titanium material according to the embodiment of the present invention. The nano-mesh structure produced at this time is no longer the nano-mesh with relatively uniform length and width in Example 1-3, nor the elongated nano-mesh in Example 4-5. The nano-structure produced at this time is mainly The nano-stripe structure in a single direction is no longer a nano-mesh structure. Therefore, the nano-mesh structure cannot be obtained under the pulse delay in this embodiment.

The above-mentioned specific descriptions further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned descriptions are only specific embodiments of the present invention, and are not intended to limit the protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. a preparation method based on the metal nano-network structure of electronic dynamic regulation, is characterized in that: comprise the steps: Step 1: The femtosecond laser single pulse is transformed into a femtosecond laser double pulse sequence with the polarization directions perpendicular to each other through the combined optical path of the Michelson interferometer and the quarter-wave plate, and then the energy of the two sub-pulses of the femtosecond laser double pulse is adjusted to be equal , at the same time, the total energy density of the double pulse is adjusted to the range of 0.9 times to 0.99 times the ablation threshold of the metal material to be processed; within the range of 9ps; Step 2: The femtosecond laser double-pulse sequence obtained in step 1 is vertically focused on the surface of the metal material to be processed through an optical lens, and the metal material to be processed is controlled to move at a set moving speed, and the metal nano-mesh can be obtained on the metal surface. like structure. 2. the preparation method of the metal nano-network structure based on electronic dynamic regulation as claimed in claim 1, is characterized in that: in described step 1 producing the femtosecond laser double pulse sequence process that polarization direction is perpendicular to each other, quarter The angle between the optical axis of the wave plate and the polarization direction of the laser is 45°. 3. the preparation method of the metal nano-mesh structure based on electronic dynamic regulation as claimed in claim 1 is characterized in that: in described step 2, when the focusing lens used is a plano-convex lens with a focal length of 100mm, the laser repetition rate is 1000Hz, and the moving speed of the metal material to be processed is 200-500μm/s. 4. The device for realizing the method according to any one of claims 1 to 3, characterized in that: comprising: a femtosecond laser, a first reflection mirror, a second reflection mirror, a first attenuator, a third reflection mirror, and a one-dimensional translation stage , beam splitter, second attenuator, quarter-wave plate, fourth mirror, fifth mirror, optical shutter, sixth mirror, seventh mirror, and eighth mirror, the polarization directions are mutually A vertical femtosecond laser double pulse sequence with a pulse delay in the range of 4ps-10ps can prepare a metal nano-mesh by scanning and processing the surface of the metal material to be processed after being focused by a lens.

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