Method and device for laser-induced plasma assisted preparation of stripe structure

Abstract

The invention provides a method and a device for laser-induced plasma assisted preparation of a stripe structure. The method comprises the following steps: S1, building a laser processing system; s2, a metal target material is placed on a displacement workbench, and the transparent hard and brittle material is located above the metal target material; s3, a laser beam emitted by a laser passes through an objective lens and the transparent hard and brittle material and then is focused on the metal target material, metal plasma transferred to the back face of the transparent hard and brittle material is induced, metal particles are deposited on the back face of the transparent hard and brittle material through the metal plasma, and laser irradiates the metal particles to excite surface plasmons, the surface plasmon interferes with incident light, so that a periodic nano stripe structure is formed; s4, the laser beam is controlled to conduct machining on the surface of the transparent hard and brittle material according to the preset machining parameters and the scanning path; and S5, the transparent hard and brittle material processed in the step S4 is placed in an absolute ethyl alcohol solution to be subjected to ultrasonic cleaning and drying.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano fabrication technology, and particularly relates to a method and apparatus for laser-induced plasma-assisted fabrication of stripe structures. Background Technology

[0002] Transparent, hard, and brittle materials, with their superior properties such as high hardness, high heat resistance, and good chemical stability, have been widely used in numerous fields including industry, electronics and semiconductors, and optical devices. Fabricating periodic nanostripes (LIPSS) on the surface of transparent, hard, and brittle materials can further endow them with special functions such as anti-reflection, friction reduction and wear resistance, and super-hydrophilic / hydrophobic surfaces, significantly expanding their application potential in key scenarios such as high-end optical windows, precision cutting tools, and biosensor chips.

[0003] Currently, mainstream methods for fabricating periodic nanostriped structures include holographic lithography, focused ion beam etching, soft lithography, nanoimprint lithography, and femtosecond laser induction. Compared with traditional micro / nano fabrication methods, femtosecond laser induction is characterized by its one-step, maskless operation, which can significantly simplify the processing flow, reduce manufacturing costs, and offers high processing efficiency, simple process steps, and no special requirements for the working environment, making it stand out among LIPSS fabrication methods. However, although the concept of laser-induced periodic surface stripe structures has been around for decades, achieving high-quality, regular periodic stripe structures on transparent, hard, and brittle materials remains a core challenge to be overcome in the field of micro / nano manufacturing. In existing research, some researchers have attempted to directly fabricate periodic nanostriped structures on the surfaces of transparent, hard, and brittle materials such as diamond and sapphire using femtosecond lasers, but the resulting periodic stripe structures have poor morphological quality, generally exhibiting defects such as fragmentation, cracks, and poor uniformity, and it is difficult to obtain high-quality stripe structures by optimizing laser parameters. To address this issue, researchers have attempted to modulate the interaction between lasers and materials by depositing metal films on the surfaces of hard and brittle materials, thereby improving the regularity of periodic stripe structures. Existing technology discloses a method for femtosecond laser-induced hyperregular nanogratings based on chromium film assistance. This method involves depositing a chromium film on hard and brittle materials such as single-crystal silicon, gallium arsenide, or sapphire using magnetron sputtering, and then fabricating a hyperregular, high-precision deep subwavelength grating array on the chromium film using a femtosecond laser. This method can adapt to different substrates to obtain micro / nano structures with corresponding grating periods. However, this patent requires pre-depositing a metal film on the surface of the hard and brittle material using magnetron sputtering, which is not only cumbersome but also increases fabrication costs. Therefore, developing a novel processing method that can achieve the effect of metal film-assisted fabrication of periodic stripe structures without requiring additional pre-deposition steps has become an urgent need in the field. Summary of the Invention

[0004] Given that existing technologies often result in material breakage and poor morphology when femtosecond lasers induce periodic nanostripes on the surface of transparent, hard, and brittle materials, and that pre-coating with metal films is complex and costly, this invention proposes a method and apparatus for laser-induced plasma-assisted preparation of stripe structures. This method enables the preparation of periodic stripe structures with the aid of metal films without the need for additional pre-coating steps.

[0005] This invention employs the following approach: a method for laser-induced plasma-assisted fabrication of stripe structures, characterized by comprising the following steps:

[0006] S1. Construct a laser processing system; wherein, the laser processing system includes a computer, a laser, a beam expander, a reflector, a CCD camera, an objective lens, and a displacement stage; S2. Install the sample fixture on the displacement worktable, place the metal target in the area below the sample fixture, and horizontally clamp the transparent hard and brittle material in the sample fixture so that the transparent hard and brittle material is above the metal target. S3. The laser beam emitted by the laser is focused on the metal target after passing through the objective lens and the transparent hard and brittle material, and induces the metal plasma to transfer to the back of the transparent hard and brittle material. The metal plasma deposits metal particles on the back of the transparent hard and brittle material. The laser irradiates the metal particles to excite surface plasmons. The surface plasmons interfere with the incident light, thereby forming a periodic nanostriped structure on the back of the transparent hard and brittle material. S4. Control the laser beam to process the surface of the transparent hard and brittle material according to the predetermined processing parameters and scanning path; S5. Place the transparent, hard, and brittle material processed in S4 into an anhydrous ethanol solution for ultrasonic cleaning and drying.

[0007] Preferably, the laser is selected from nanosecond, picosecond, or femtosecond lasers and meets the parameter requirements for the formation of periodic nanostripe structures: the number of laser pulses in a single laser irradiation area is 1-100; the laser wavelength must be able to penetrate hard and brittle materials and avoid being absorbed, so as to ensure that the laser energy is effectively applied to the metal target to induce plasma generation.

[0008] Preferably, the metal target is one of gold, silver, titanium, chromium, iron, cobalt, copper, nickel, aluminum, and tin.

[0009] Preferably, the transparent hard and brittle material is one of diamond, sapphire, glass, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, and fused silica.

[0010] Preferably, the transparent hard and brittle material and the metal target are arranged vertically and spaced apart by a distance of less than 500 micrometers.

[0011] Preferably, in step S3, the laser focus positioning process is monitored in real time by the CCD camera.

[0012] A device for laser-induced plasma-assisted preparation of stripe structures, characterized in that the stripe structures are prepared using the laser-induced plasma-assisted preparation method described above.

[0013] By adopting the above technical solution, the present invention achieves the following technical effects: The present invention effectively avoids the problems of fragmentation and cracking easily caused by periodic nanostriped structures on the surface of transparent, hard, and brittle materials induced by femtosecond lasers. Indirect processing using metal plasma enables the acquisition of high-quality periodic nanostriped structures on transparent, hard, and brittle materials. The present invention eliminates the cumbersome step of pre-plating a metal film, simultaneously achieving metal deposition and nanostriped structure processing through "laser-induced plasma," realizing single-step processing, greatly simplifying the process flow, and reducing equipment investment and production costs. Furthermore, the present invention allows for flexible control of plasma composition by changing different metal targets, making the processing method more flexible and adaptable to different processing needs. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the apparatus for preparing periodic nanostripes from transparent, hard, and brittle materials by laser-induced plasma-assisted ablation, as provided in an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram illustrating the principle of preparing periodic nanostripes from transparent, hard, and brittle materials by laser-induced plasma-assisted ablation.

[0017] Figure 3 (a) is a scanning electron microscope image of the nanostriped structure processed on diamond by femtosecond laser-induced copper plasma when using metallic copper as the target material in an embodiment of the present invention.

[0018] Figure 3 (b) is Figure 3 (a) The corresponding magnified scanning electron microscope image.

[0019] In the figure: 1-computer, 2-laser, 3-beam expander, 4-mirror, 5-CCD camera, 6-objective lens, 7-sample fixture, 8-transparent hard and brittle material, 9-metal target, 10-displacement stage. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] Example This invention proposes a method for preparing periodic nanostriped structures by laser-induced plasma-assisted ablation of transparent, hard, and brittle materials. This method relies on a micro / nano structure fabrication system. Before describing the method for preparing periodic nanostriped structures by laser-induced plasma-assisted ablation of transparent, hard, and brittle materials provided in the embodiments of this invention, the micro / nano structure fabrication system will be described first.

[0026] Reference manual attached Figure 1 The micro / nano structure fabrication system provided in this embodiment of the invention includes: a computer 1, a laser processing system, a sample holder 7, a transparent hard and brittle material 8, a metal target 9, and a displacement stage 10; the laser processing system includes a laser 2, a beam expander 3, a reflector 4, a CCD camera 5, and an objective lens 6; the metal target 9 is fixed on the displacement stage 10, and the position of the metal target 9 is controlled by the displacement stage 10; the sample holder 7 holds the transparent hard and brittle material 8 to be processed, and the transparent hard and brittle material 8 and the metal target 9 are arranged vertically with a fixed distance between them; the laser... The laser beam emitted by 2 is expanded by beam expander 3 and reflected by mirror 4, then focused onto metal target 9 by objective lens 6 and transparent hard and brittle material 8, inducing metal plasma to act in the opposite direction on the back of the transparent hard and brittle material. This utilizes laser ablation of the metal target to generate metal plasma and cause it to deposit in the opposite direction, dynamically forming a layer of metal nanoparticles. Further laser irradiation of these particles excites surface plasmons, which interfere with the incident laser, thus forming a periodic nanostriped structure on the hard and brittle material. This achieves metal deposition and nanostriped structure processing on the back of the transparent hard and brittle material. Specifically, the sample fixture 7 includes two grippers mounted on a displacement stage, and the height of the transparent hard and brittle material 8 to be processed is adjusted by a micrometer screw gauge. The objective lens 6 has a numerical aperture of 0.4, a magnification of 20x, and a spot diameter of 10 micrometers. The metal target 9 is a copper target. The CCD camera 5 monitors the laser focusing process and processing effect in real time.

[0027] Reference manual attached Figure 2 The core principle of the method of this invention is as follows: the laser beam penetrates the transparent hard and brittle material (such as diamond, sapphire, glass, silicon carbide, etc., which have high hardness and strong chemical stability, but do not have thermal response or phase change characteristics) and focuses on the surface of the metal target below. The laser ablation induces the metal target to generate metal plasma. The plasma diffuses in the reverse direction and is adsorbed on the back side of the transparent hard and brittle material. The incident light interferes with the surface plasmons excited by the metal particles, thereby realizing the simultaneous deposition of metal particles and the processing of periodic nano-stripes without the need for pre-depositing a metal film.

[0028] The following detailed description, in conjunction with specific embodiments, illustrates a method for preparing periodic nanostripe structures using the aforementioned apparatus: In this embodiment, a femtosecond laser is used with a wavelength of 1030 nm, a repetition rate of 500 kHz, a pulse width of 300 fs, a pulse number of 7, and 6 scans. The transparent, hard, and brittle material being processed is single-crystal diamond prepared by chemical vapor deposition, with dimensions of 3 mm × 3 mm and a thickness of 1 mm. A copper target is selected as the metal target, with dimensions of 50 mm in diameter and 5 mm in thickness. The specifications and material type of the metal target can be flexibly adjusted according to actual needs. The method specifically includes the following steps: Step 1: Install the sample fixture on the displacement stage and place the metal target in the area below the sample fixture; Step 2: Hold the diamond to be processed horizontally between the two jaws of the sample holder, and adjust the distance between the diamond to be processed and the metal target material using a micrometer screw gauge, which is between 0-500 micrometers. In this embodiment, 0 micrometers is used. Step 3: The laser beam emitted by the femtosecond laser is focused onto the metal target through the objective lens and the transparent hard and brittle material. The laser induces metal plasma to transfer to the back of the transparent hard and brittle material. The metal plasma deposits metal particles on the back of the transparent hard and brittle material. The laser irradiates the metal particles to excite surface plasmons. The surface plasmons interfere with the incident light, thereby forming a periodic nanostriped structure. In this embodiment, the laser power is set to 1W, but other laser powers can be selected as needed. Step 4: Control the laser beam to process the diamond surface along a predetermined scanning path; in this embodiment, the laser beam is set to scan in a straight line, but other scanning paths can also be used as needed; Step 5: Place the diamond processed according to the above method in an anhydrous ethanol solution for ultrasonic cleaning and then dry it.

[0029] Instruction manual attached Figure 3 These are scanning electron microscope images of periodic nanostripe structures fabricated on the back of diamond using this processing method with metallic copper as the target material. Figure 3It can be seen that the periodic nanostripes prepared by this method have no obvious defects such as fragmentation or cracks, and have excellent morphological quality.

[0030] The present invention provides the preferred embodiments described above. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for laser-induced plasma-assisted fabrication of stripe structures, characterized in that, Includes the following steps: S1. Construct a laser processing system; wherein, the laser processing system includes a computer, a laser, a beam expander, a reflector, a CCD camera, an objective lens, and a displacement stage; S2. Install the sample fixture on the displacement worktable, place the metal target in the area below the sample fixture, and horizontally clamp the transparent hard and brittle material in the sample fixture so that the transparent hard and brittle material is above the metal target. S3. The laser beam emitted by the laser is focused on the metal target after passing through the objective lens and the transparent hard and brittle material, and induces the metal plasma to transfer to the back of the transparent hard and brittle material. The metal plasma deposits metal particles on the back of the transparent hard and brittle material. The laser irradiates the metal particles to excite surface plasmons. The surface plasmons interfere with the incident light, thereby forming a periodic nanostriped structure on the back of the transparent hard and brittle material. S4. Control the laser beam to process the surface of the transparent hard and brittle material according to the predetermined processing parameters and scanning path; S5. Place the transparent, hard, and brittle material processed in S4 into an anhydrous ethanol solution for ultrasonic cleaning and drying.

2. The method for laser-induced plasma-assisted fabrication of stripe structures according to claim 1, characterized in that, The laser is selected from nanosecond, picosecond, or femtosecond lasers and meets the parameter requirements for the formation of periodic nanostripe structures: the number of laser pulses in a single laser irradiation area is 1-100; the laser wavelength must be able to penetrate hard and brittle materials and avoid being absorbed, so as to ensure that the laser energy is effectively applied to the metal target to induce plasma generation.

3. The method for laser-induced plasma-assisted fabrication of stripe structures according to claim 1, characterized in that, The metal target material is one of gold, silver, titanium, chromium, iron, cobalt, copper, nickel, aluminum, and tin.

4. The method for laser-induced plasma-assisted fabrication of stripe structures according to claim 1, characterized in that, The transparent, hard, and brittle material is one of diamond, sapphire, glass, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, and fused silica.

5. The method for laser-induced plasma-assisted fabrication of stripe structures according to claim 1, characterized in that, The transparent, hard, and brittle material and the metal target are arranged vertically and spaced apart by a distance of less than 500 micrometers.

6. The method for laser-induced plasma-assisted fabrication of stripe structures according to claim 1, characterized in that, In step S3, while the laser is focusing, the laser focus positioning process is monitored in real time by the CCD camera.

7. A device for laser-induced plasma-assisted fabrication of stripe structures, characterized in that, The stripe structure is prepared using the laser-induced plasma-assisted stripe structure preparation method as described in any one of claims 1-6.

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