CN114221208B

CN114221208B - Nanometer array preparation system and nanometer array preparation method

Info

Publication number: CN114221208B
Application number: CN202111367350.8A
Authority: CN
Inventors: 徐少林; 黄佳旭; 徐康
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2023-07-21
Anticipated expiration: 2041-11-18
Also published as: CN114221208A

Abstract

The invention discloses a nano array preparation system and a nano array preparation method. Wherein, the nano-array preparation system includes: the laser is used for generating laser and generating a first nano array by irradiation on a first path of the substrate; the controller is connected with the laser; the displacement table is used for bearing the substrate; the laser comprises a beam shaping module, wherein the beam shaping module is used for generating a flat-top line focusing beam; the controller is also used for controlling the displacement table to move a preset distance so as to enable the laser to irradiate on a second path of the substrate to generate a second nano array; the first nano array and the second nano array are arranged in a staggered mode, and a honeycomb-like two-dimensional nano structure is generated in continuous scanning. The preparation method of the nano array can realize the efficient large-area preparation of the nano array.

Description

Nanometer array preparation system and nanometer array preparation method

Technical Field

The invention relates to the technical field of nano-array preparation, in particular to a nano-array preparation system and a nano-array preparation method.

Background

The nano array is used as a periodic surface structure, and is widely used in various fields due to its special optical properties.

However, in the related art, it is still difficult to achieve efficient large-area preparation of uniform nano-arrays.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a nano array preparation system and a nano array preparation method, which can realize the efficient large-area preparation of the nano array.

In a first aspect, the present application provides a nanoarray preparation system applied to a substrate, comprising: the laser is used for generating laser and generating a first nano array by irradiation on a first path of the substrate; the controller is connected with the laser; a displacement table for carrying the substrate; the laser comprises a beam shaping module, wherein the beam shaping module is used for generating a flat-top line focusing beam; the controller is also used for controlling the displacement table to move for a preset distance so that the laser irradiates on a second path of the substrate to generate a second nano array; wherein the first nanoarray comprises a plurality of first nanosubarrays and the second nanoarray comprises a plurality of second nanosubarrays; the adjacent first nanometer subarrays are separated by a first interval, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second interval in the vertical direction of a second path, and the second interval is half of the first interval.

According to the embodiment of the application, the wavelength, the polarization direction, the single pulse energy and the movement speed of the displacement table of the laser generated by the laser are regulated, so that corresponding nano arrays with different periods, different structure types (dot matrix or hole array), different orientations and different unit lengths can be generated on the substrate in a scanning mode, and the shape, the length, the orientation and other structural characteristics of the prepared nano array units are controllable. Meanwhile, the substrate is irradiated by the uniform flat top line light source, so that synchronous preparation of a plurality of sub-wavelength nano subarrays in the long axis direction of the line light source can be realized in single irradiation, and the preparation efficiency and the uniformity of the nano subarrays are improved. The size of the prepared nano array is in the sub-wavelength level, and the preparation process is not influenced by diffraction limit and focusing light spots because the periodic partial ablation is carried out by utilizing the excited surface plasmon wave. By regulating and controlling the overlapping rate of the irradiation area of the laser light spot, the self-aligned growth of the nano array is realized by utilizing the grating coupling effect and the surface wave periodic interference enhancement excited in the preparation process, and the efficient large-area preparation of the nano array is realized without additional complex splicing alignment steps when the nano array with a large area is prepared.

In some embodiments, the nanoarray preparation system further comprises: the imaging device is connected with the laser and is used for collecting images of the substrate processed by the laser; the controller is further used for calculating the preset distance according to the image, and the controller controls the displacement table to move according to the preset distance.

In some embodiments, the imaging device comprises: the LED light source is used for emitting monochromatic light; the imaging lens group is connected with the LED light source and used for irradiating the monochromatic light to the substrate and collecting reflected light; and the CMOS camera is connected with the imaging lens group and used for acquiring the reflected light and generating the image.

In a second aspect, the present application provides a method for preparing a nano-array, which is applied to the nano-array preparation system described in any one of the above embodiments, where the method for preparing a nano-array includes:

controlling the laser to generate laser;

generating a first nano array according to the irradiation of the laser on a first path of the substrate;

controlling the displacement table to move a preset distance so that the laser irradiates on a second path of the substrate to generate a second nano array;

wherein the first nanoarray comprises a plurality of first nanosubarrays and the second nanoarray comprises a plurality of second nanosubarrays; the adjacent first nanometer subarrays are separated by a first interval, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second interval in the vertical direction of a second path, and the second interval is half of the first interval.

In some embodiments, the preset distance is within a preset threshold interval.

In some embodiments, the laser is a line light source.

In some embodiments, the spot of laser light irradiated along the second path at least partially overlaps the first nanoarray.

In some embodiments, the first nanoarray and the corresponding second nanoarray form a nanoarray set; the nano array group comprises a plurality of the first nano subarrays and a plurality of the second nano subarrays; the nano array preparation method further comprises the following steps:

and controlling the substrate to move for a preset distance, and executing the step again to control the laser to generate the laser so as to irradiate the laser on the substrate to generate the nano array group.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The invention is further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic diagram of a nano-array preparation system according to the present invention;

FIG. 2 is a schematic diagram of a nanoarray of the nanoarray fabrication system of the invention;

FIG. 3 is a schematic diagram of a nanolattice scanning electron micrograph of a nanoarray fabrication system according to the present invention;

FIG. 4 is a scanning electron micrograph of a nanopore array of the nanoarray preparation system of the present invention;

FIG. 5 is a flow chart of a method for preparing a nano-array according to the present invention.

Reference numerals: 100. a nano-array preparation system; 110. a laser; 111. an ultrafast light source; 112. an energy adjustment module; 1121. a half-wave plate; 1122. a gram prism; 113. a beam expansion collimation module; 1131. a first convex lens; 1132. a first concave lens; 114. a beam shaping module; 1141. a first mirror; 1142. a second mirror; 1143. a spatial modulator; 1144. a second convex lens; 1145. a third convex lens; 1146. a polarizing plate; 115. a dichroic mirror; 116. a focusing module; 1161. a cylindrical convex lens; 120. an imaging device; 121. an LED light source; 122. a third mirror; 123. a beam splitter; 124. a CMOS camera; 130. a substrate; 140. a displacement table; 150. and a controller.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a number is one or more, the meaning of a number is two or more, and greater than, less than, exceeding, etc. are understood to exclude the present number, and the meaning of a number is understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

In the description of the present invention, the descriptions of the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The displacement table is used for bearing the substrate and controlling the movement of the substrate. The two-dimensional nano array structure with a certain period can be prepared on the substrate by a laser irradiation method. Wherein, the two-dimensional nano array is a surface periodic structure constructed by a large number of nano array units (nano subarrays) with equal size and equal spacing. However, according to the conventional technology, the induced nano array structure is difficult to realize the characteristic of long-range order, and the type and uniformity of the nano structure generated by laser induction have certain limitations. The nano array generated by laser irradiation is a one-dimensional nano array with limited length and size in a light spot irradiation area, namely the area of the nano array generated by laser irradiation is limited. Meanwhile, the method for inducing the periodic surface structure by laser relies on periodic ablation caused by interference of surface plasma laser waves and incident light, the obtained nano structure is a one-dimensional grating structure in nature, and the obtained structure array can be expanded from a one-dimensional grating to a two-dimensional nano array to a certain extent through various complex light field regulation and control or multi-effect coupling, but the method still depends on specific processing working conditions and complex light paths, and is difficult to obtain the two-dimensional nano array with long-range order in a high-efficiency large-area mode.

Referring to fig. 1 to 4, the present application provides a nano-array preparation system 100, which is applied to a substrate 130, the nano-array preparation system 100 includes: a laser 110 for generating laser light and for generating a first nanoarray 1 by irradiation on a first path of the substrate 130; a controller 150 connected to the laser 110; a displacement stage 140 for carrying the substrate 130; wherein the laser 110 includes a beam shaping module 114, the beam shaping module 114 is configured to generate a flat-top line focused beam; the controller 150 is further configured to control the displacement stage 140 to move by a preset distance, so that the laser irradiates on a second path of the substrate 130 to generate a second nano array 2; wherein the first nano-array 1 comprises a plurality of first nano-subarrays, and the second nano-array 2 comprises a plurality of second nano-subarrays; the adjacent first nanometer subarrays are separated by a first interval, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second interval in the vertical direction of a second path, and the second interval is half of the first interval.

It will be appreciated that ultra-fast lasers are capable of irradiation at the surface of a material to produce periodic structures. When the energy density of the incident laser is near or above the material damage threshold, the incident laser will generate a periodic structure on the surface of the material. The material may be a solid material such as a metal or a semiconductor, or may be a thin film. When substrate 130 is irradiated with ultra-short pulse laser energy approaching its own damage threshold, the laser-excited surface plasmon waves will interfere with the incident light and form a periodic locally enhanced electromagnetic field energy distribution, and when the local electromagnetic field energy intensity exceeds the material ablation threshold of substrate 130, periodic ablation of the material will be induced and stable surface periodic structures will be produced. Furthermore, the acting characteristic size of the local enhancement field on the surface of the material is in the sub-wavelength level, so that the periodic structure characteristic of the nano array prepared by the embodiment is super-diffraction limit.

Specifically, the laser 110 is configured to generate a femtosecond pulse laser required for preparing the nano-array on the substrate 130. The laser 110 includes an ultrafast light source 111, an energy adjustment module 112, a beam expansion and collimation module 113, a beam shaping module 114, and a focusing module 116. The ultrafast light source 111 is used for emitting femtosecond Gaussian linear polarized pulse laser with adjustable laser repetition frequency. The energy adjustment module 112 is configured to perform single pulse energy adjustment and control on the femtosecond gaussian linear polarization pulse laser emitted by the ultrafast light source 111, so as to obtain an energy-adjustable gaussian beam. The gaussian beam is an electromagnetic beam whose transverse electric field and irradiance distribution approximately satisfy a gaussian function. Specifically, the energy adjustment module 112 is composed of a half-wave plate 1121 and a graticule prism 1122. Because the pulse laser is emitted by a large number of photons concentrated in a very small time range, the energy density is very high, and the output power is high; by calculating the average power P of the pulsed laser over a period of operation (i.e., the amount of energy consumed per unit time) and the repetition rate f of the pulsed laser (i.e., the number of laser pulses emitted per unit time), the single pulse energy J can be derived from the following calculation formula:

the Gaussian beam spot subjected to energy modulation is subjected to beam expansion collimation through a beam expansion collimation module 113, and a beam expansion collimation spot is obtained. The beam expansion and collimation module 113 includes a first concave lens 1132 and a first convex lens 1131. The beam expansion collimation module 113 is capable of changing the diameter and divergence angle of the gaussian beam. The laser emitted from the ultrafast light source 111 has a certain divergence angle after being modulated by the energy adjusting module 112, and in order to obtain a laser spot with high power density, the divergence angle of the laser needs to be adjusted so that the gaussian beam becomes a collimated (parallel) beam; the diameter of the laser spot is enlarged before the laser beam is focused, thereby obtaining a smaller focused spot. Therefore, the first concave lens 1132 and the first convex lens 1131 of the beam expansion and collimation module 113 can improve the collimation characteristic of the light beam and the focusing degree of the light spot. The beam-expanding collimated light spot exits from the beam-expanding collimating module 113 and enters the beam shaping module 114. The beam shaping module 114 includes a first mirror 1141, a spatial modulator 1143, a second convex lens 1144, a second mirror 1142, a third convex lens 1145, and a polarizer 1146. The beam shaping module 114 can obtain flat-top light spots with uniform energy distribution and steep boundaries and specific shapes. When the beam-expanding collimated light spot is subjected to homogenization treatment by the beam shaping module 114, the energy of the light spot is uniformly distributed, and the incident Gaussian beam is shaped into a flat-top beam. The energy density of a certain area of the flat-top beam in the propagation section is almost uniform. After passing through the polarizer 1146 in the beam shaping module 114, the flat-top beam is modulated by the polarization of the linear polarization flat-top beam, and the polarization angle of the linear polarization flat-top beam can be obtained by adjusting the angle of the polarizer 1146 according to actual needs. The expanded collimated gaussian beam, after passing through the beam shaping module 114, can obtain a linear polarization flat-top beam of a specific polarization state.

Specifically, the linear polarization flat-top beam is reflected by the dichroic mirror 115 and then enters the focusing module 116. The dichroic mirror 115, also called a dichroic mirror, is characterized by almost completely transmitting light of a certain wavelength and almost completely reflecting light of another wavelength. In this embodiment, dichroic mirror 115 is fully reflective to the linear polarized flat-top beam. The focusing module 116 includes a cylindrical lens 1161, and the linear polarization flat-top beam is focused into a linear beam by the flat-top beam after being focused by the cylindrical lens 1161, that is, the linear polarization flat-top beam is changed into a linear polarization uniform linear beam.

It can be understood that the ultrafast light source 111 emits femtosecond gaussian linear polarized pulse laser, the gaussian beam sequentially passes through the energy adjustment module 112 composed of the half-wave plate 1121 and the glaring prism 1122 for laser energy adjustment, and further passes through the beam expansion collimation module 113 composed of the first convex lens 1131 and the first concave lens 1132 for laser expansion; the beam-expanded laser enters a beam shaping module 114 consisting of a spatial modulator 1143, a second convex lens 1144, a second reflecting mirror 1142, a third reflecting mirror 122, a third convex lens 1145 and a polaroid 1146 through a first reflecting mirror 1141, so as to generate linear polarization flat-top beams; and then reflected by the dichroic mirror 115 to be incident on the lenticular lens 1161. The modulated flat top beam enters the lenticular lens 1161 focusing module 116 to obtain a uniform flat top line light source with a specific polarization state. A uniform flat top line light source with a specific energy, polarization state, wavelength is finally output by the laser 110. The uniform flat top line light source is irradiated onto the surface of the substrate 130, and the focal position of the uniform flat top line light source is adjusted to the surface of the substrate 130 by adjusting the distance between the lenticular lens 1161 and the substrate 130. The controller 150 is used to control the displacement table 140 to be linked with the ultrafast light source 111, so as to realize that the uniform flat top linear light source prepares the nano array on the surface of the substrate 130.

It can be appreciated that the method of generating the periodic structure of the laser-induced surface by irradiation of the uniform flat-top light source generated by the laser 110 in this embodiment prepares the nano-array structure on the substrate 130. Specifically, the light spot 3 of the uniform flat-top line light source (i.e. the shaded portion in fig. 2) is focused on the first path of the substrate 130, and meanwhile, the polarization of the incident light is parallel to the long axis direction of the light spot, so that the laser light spot 3 of the uniform flat-top line light source generates uniformly arranged first nano arrays 1 on the first path of the substrate 130, and the first nano arrays 1 are generated along the long axis direction of the light spot 3 of the uniform flat-top line light source to form a periodic nano dot/hole array. Wherein the substrate 130 may be a solid material, a thin film. And then, the pulse repetition frequency of the laser 110 for generating laser and the movement speed of the displacement table 140 are adjusted, so that the distance between the first nano array 1 and the irradiation area of the light spot 3 on the second path is indirectly controlled, and after the substrate 130 moves along the short axis direction of the uniform flat top line light source by a preset distance, the laser light spot 3 is focused on the second path of the substrate 130, and the second nano array 2 is generated by irradiation. Sub-arrays in irradiation areas of laser spots 3 on different paths are independently generated, namely sub-arrays among different scanning paths lack of an effective coupling mechanism to cause random generation positions, so that the nano arrays generated on a first path and a second path of different laser irradiation are generated in a non-aligned mode, namely the first nano array 1 and the second nano array 2 are not uniformly arranged, and therefore the structure prepared by the method is disordered in a long range. In this embodiment, by controlling the substrate 130 to move by a preset distance, the light spot 3 of the uniform flat-top line light source is focused on the second path of the substrate 130, and at the same time, the light spot 3 of the uniform flat-top line light source on the second path covers the first nano array 1 on the first path that is partially generated, and the formed first nano array is used as a uniform nano scatterer, so that interference of excited surface plasmon waves is generated between adjacent sub-arrays of the first nano array, and energy redistribution of surface propagation electromagnetic waves can be realized in subsequent irradiation of the second path. Due to the existing structure of the first nano-array 1 as the surface of the substrate 130, under the radiation of the incident laser, the first nano-array 1 makes the energy for generating the second nano-array 2 generate uniform periodic directional distribution. And (3) at the position of the half-period dislocation of the first nano array 1, the second nano array which is in half-period dislocation with the first nano array 1 is formed by ablation due to the concentration of light field energy distribution caused by exciting surface plasmon waves, so that the nano arrays grow in a self-aligned mode. The preset distance is the distance between a first path of the first nano array 1 generated by the uniform flat-top line light source and a second path of the second nano array 2 generated by the uniform flat-top line light source.

It will be appreciated that, due to the redistribution of the energy of the incident laser light and the surface plasmon wave, an optical enhancement effect will be produced at the corresponding location of the generated first nanoarray 1 and ablate out the second nanoarray 2. Specifically, the second nano subarray generated by self-alignment and the corresponding first nano subarray are in half-period dislocation, namely the second nano subarray generated subsequently can be generated by self-alignment on an extension line of the adjacent first nano subarray from the central line and on a second path of laser irradiation.

It can be understood that in the process of the self-aligned growth of the two-dimensional array, due to the grating coupling effect and the interference enhancement of surface plasmon waves, the self-aligned characteristic of the grown nano-unit array has robustness, namely, the local structural disorder caused by chip or substrate surface defects in the processing process can be gradually corrected in the process of the self-aligned growth of the subsequent nano-unit array, and finally the self-aligned growth of the long-range ordered two-dimensional nano-array is realized.

Specifically, the pulse repetition frequency, wavelength and single pulse energy of the laser emitted by the ultrafast light source 111 and the moving speed of the displacement table 140 are controlled, so that the uniform flat top line light source generates the first nano array 1 along the first path of the substrate 130, where the first nano array 1 includes a plurality of uniformly arranged first nano sub-arrays, and the transverse arrangement direction (the direction of the first path) of the plurality of first nano sub-arrays is parallel to the uniform flat top line light source. The first nano subarrays have the same distance with the adjacent first nano subarrays in the first path direction, and the distance is the period of the first nano array 1. After the controller 150 controls the displacement stage 140 to move a preset distance, the uniform flat top line light source irradiates along the second path to generate the second nano array 2. Similarly, the second nano-array 2 also includes a plurality of second nano-sub-arrays which are uniformly distributed, and the uniformly distributed intervals are the periods of the second nano-array 2. The period of the nano-arrays (including the first nano-array 1 and the second nano-array 2), i.e. the sub-array spacing of the nano-arrays in this embodiment, is related to the wavelength of the laser light generated by the laser 110. The nano arrays with different interval distribution (different periods) can be obtained by regulating and controlling the wavelength of the emergent laser, namely the uniform flat top line light source. In addition, the period for preparing the nano array can be further controlled by changing the incident angle between the incident light and the surface of the substrate 130 and the processing environment medium, such as preparing in liquid. Specifically, by controlling the energy adjustment module 112 in the laser 110, the single pulse energy J of the processing laser is controlled, so that the structure type of the nano array formed by ablation can be controlled. In the process of preparing the nano array, different energy excitations can cause different energy distributions, and finally form a nano lattice array or a nano hole array. As shown in fig. 3 and 4, the substrate 130 in fig. 3 is a raised nano-lattice, and the substrate 130 in fig. 4 is a recessed nano-pore lattice. For example, when the laser pulse repetition frequency is 1kHz and the laser single pulse energy is 2.37 μj, i.e., the low energy excitation, the surface plasmon wave excitation is weak, so that the incident light energy (long axis direction of the light spot 3) and the surface plasmon wave (short axis direction of the light spot 3) will jointly cause ablation, thereby generating the nano lattice array. When the laser single pulse energy is 2.66 mu J, namely when high energy excitation is carried out, the surface plasmon wave excitation is extremely strong, the incident light field energy is concentrated to the position in the circle in fig. 2, and finally the generation of the nanopore array is caused.

Specifically, by adjusting the direction of the polarizing plate 1146 of the beam shaping module 114 in the laser 110, the polarization direction of the generated uniform flat top line light source is changed, and the scanning direction of the uniform flat top line light source on the substrate 130 (the long axis direction of the uniform flat top line light source) is combined. The adjustment and control of the orientation of the nano subarray in the nano array structure can be realized by controlling the included angle between the polarization direction of the uniform flat top line light source and the long axis direction of the uniform flat top line light source to change from 0 degrees to 90 degrees.

Specifically, by adjusting the movement speed of the displacement table 140, that is, the scanning speed of the uniform flat-top line light source scanning substrate 130, the pulse separation distance of the light spots 3 of the uniform flat-top line light source can be changed, so as to change the array unit length of the generated nano array structure, that is, control the morphology of the nano subarray, for example, prepare a circular, circular-like or long-strip-shaped nano subarray, or even a circular, circular-like and long-strip-shaped mixed structure.

Specifically, the control substrate 130 is moved by a predetermined distance by controlling the repetition frequency f of the pulsed laser light emitted from the laser 110 and the movement speed of the displacement stage 140. The displacement table 140 is controlled to move at a uniform speed by the controller 150, so that the light spots 3 of the uniform flat top line light source are irradiated on different paths of the substrate 130. For example, the laser pulse repetition frequency is 1kHz, the laser single pulse energy is between 2.1 μj and 3.1 μj, and the moving speed of the displacement stage 140, that is, the moving speed of the substrate 130 is between 0.4mm/s and 1mm/s, so as to control the overlapping rate N of the laser pulses. The overlapping ratio of the laser pulses represents the preset distance between different paths of the substrate 130, and the overlapping ratio of the laser pulses can be obtained by the following calculation formula:

where d is the spot 3 size of the processing laser (i.e., the uniform flat top line source in this embodiment), and v is the velocity of movement of the displacement stage 140. In this embodiment, by controlling the pulse overlap ratio N to be greater than or equal to 2.1 and less than or equal to 5.25, the structure prepared by the previous irradiation laser on the adjacent preparation paths redistributes and regulates the electromagnetic field of the subsequent incident laser on the surface of the material, so as to generate the optical enhancement effect of half-period dislocation relative to the formed nano array structure. Thereby causing ablation of the half-cycle misalignment relative to the generated structure, i.e., the second nanosubarray is generated in a second path with a misalignment of half-cycles of the corresponding generated first nanosubarray. Resulting in a cellular-like distributed nano-array structure as described in fig. 2 to 4. For different nano-array preparation requirements, different light spot 3 sizes, different laser wavelengths, different laser single pulse energy sizes and different scanning speeds (movement speeds of the substrate 130) are required, and then the pulse overlap rate N is also required to be correspondingly adjusted. In this regard, this embodiment is not described in detail herein.

It can be appreciated that when the uniform flat top line light source generated by the laser 110 irradiates on the first path or other paths in this embodiment, the nano subarrays uniformly distributed on the paths can be prepared by single irradiation. And by controlling the pulse overlapping rate of the emergent laser, namely regulating and controlling the interval (preset distance) of the irradiation paths of the uniform flat top line light source, the irradiation paths of laser irradiation can generate light field energy enhancement at the positions corresponding to the adjacent generated nano arrays, so that the nano arrays with staggered half periods are generated in a self-aligned manner on the laser irradiation paths, and the large-area uniform preparation of the two-dimensional nano arrays is realized. The nano array can be prepared by combining the uniform flat top line light source for single scanning, and the high-efficiency large-area preparation of the uniform nano array can be realized.

According to the embodiment of the application, through regulating and controlling the wavelength, the polarization direction, the single pulse energy and the movement speed of the displacement table 140 of the laser 110, the corresponding nano arrays with different periods, different structure types (dot matrix or hole array), different orientations and different unit lengths can be scanned and generated on the substrate 130, and the shape, the length, the orientation and other structural characteristics of the prepared nano array units are controllable. Meanwhile, the uniform flat top line light source is utilized for scanning, so that the preparation efficiency and the uniformity of the nano subarray are improved. Since the size of the prepared nano array is in the sub-wavelength level, the preparation process is not affected by diffraction limit and focusing light spots. By regulating and controlling the overlapping rate of the laser light spots, the grating coupling effect and the surface wave periodic interference enhancement excited by the uniform linear light source on the surface of the uniform nano array in the preparation process are utilized to cause the uniform periodic uniform light field enhancement on the surface of the substrate, the self-aligned growth of the nano array is further realized, no additional complex splicing alignment step is needed in the preparation of the large-area nano array, and the efficient large-area preparation of the nano array is realized.

Referring again to fig. 1, in some embodiments, the nanoarray preparation system 100 further comprises: an imaging device 120, connected to the laser 110, for collecting an image of the substrate 130 processed by the laser 110; the controller 150 is further configured to calculate the preset distance according to the image, and the controller 150 controls the displacement table 140 to move according to the preset distance.

Specifically, the imaging device 120 is configured to perform image acquisition during the laser processing of the substrate 130. The preparation of the nano-array on the substrate 130 can be observed in real time by the imaging device 120. According to the obtained material ablation image of the processing process of the substrate 130, the relative position of the lenticular lens 1161 and the surface of the substrate 130 can be further adjusted according to the image information, so that the light spot focus is focused on the surface of the substrate 130, and the preparation of the nano array is realized.

Referring again to fig. 1, in some embodiments, the imaging device 120 includes: an LED light source 121 for emitting monochromatic light; an imaging lens group connected to the LED light source 121 for irradiating the monochromatic light onto the substrate 130 and collecting reflected light; and a CMOS camera 124 connected to the imaging lens group for acquiring the reflected light and generating the image.

Specifically, the imaging lens group includes a beam splitter 123 and a third mirror 122. In the process of preparing the nano array, the LED light source 121 emits monochromatic light, the monochromatic light is reflected by the beam splitter 123, sequentially passes through the dichroic mirror 115 and the focusing objective lens to the surface area of the substrate 130, then propagates along an incident path, sequentially passes through the focusing objective lens, the dichroic mirror 115 and the beam splitter 123, finally enters the CMOS camera 124 through the third reflector 122 to form an image, and real-time observation of the state of preparing the nano array by the uniform flat-top line light source on the substrate 130 is realized.

Referring to fig. 1 to 5, in a second aspect, an embodiment of the present application provides a method for preparing a nano-array, which is applied to the nano-array preparation system 100 described in any one of the above embodiments, including:

step S101, controlling a laser to generate laser;

step S102, the displacement table is controlled to move a preset distance.

The laser is used for generating a first nano array 1 by irradiation on a first path of the substrate 130; controlling the displacement table 140 to move a preset distance so that the laser irradiates on a second path of the substrate 130 to generate a second nano array 2; wherein the first nano-array 1 comprises a plurality of first nano-subarrays, and the second nano-array 2 comprises a plurality of second nano-subarrays; the adjacent first nanometer subarrays are separated by a first distance, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second distance in the direction of a second path, and the second distance is half of the first distance.

It will be appreciated that a uniform flat top line light source with tunable laser parameters is generated by the laser 110 and is irradiated onto the processed substrate 130 to scan to generate the nanoarray. By adjusting and controlling the movement speed of the displacement table 140 and the laser repetition frequency of the laser 110, the interval between the uniform flat top line light sources in adjacent irradiation paths, that is, the preset distance, can be changed, so that the energy of the surface plasma laser wave excited by the incident laser and the surface of the substrate 130 is redistributed, and the optical field enhancement is generated on the second path with the generated half-period dislocation of the first nano array 1, so that the second nano array 2 is generated in a self-alignment manner relative to the first nano array 1. Self-aligned half-cycle dislocation generation of any adjacent nano-array is realized.

Specifically, according to different laser parameters and types of the generated nano array structures, the movement speed of the corresponding displacement table 140 can be set. For example, when the laser parameters are: the laser wavelength is 520nm, the pulse width is 300fs, the laser single pulse energy is 2.66 mu J, the short axis size of the light spot 3 is 2.1 mu m, the laser pulse repetition frequency is 1kHz, the substrate movement speed is 0.4-1mm/s, namely, when the pulse overlapping rate is 2.1-5.25, a uniform nano hole array is generated.

It will be appreciated that as shown in fig. 2, a uniform flat top line light source irradiates on the substrate 130 and generates the first nanoarray 1, and the displacement stage 140 moves at a uniform speed so that the laser scans along the substrate 130. The subsequently irradiated laser spot 3 is focused on the second path and partially covers the first nanoarray 1 and ablates to produce said second nanoarray 2, it being understood that within this pulse overlap ratio range, the incident laser can support excitation of sufficient carrier concentration to produce a surface plasmon wave to effect periodic ablation of the surface of the substrate 130. Further, in the scanning process, when the light spot 3 of the uniform flat top line light source is on the second path, the coverage area of the light spot 3 is partially overlapped with part of the first nano array 1 in the first path, the first nano array 1 on the surface of the substrate 130 is used as a row of periodic repeating units with consistent period and good regularity, and can generate consistent periodic modulation on the incident light energy, namely, by the surface plasmon wave interference of adjacent structures, the energy is generated between the adjacent nano sub arrays of the first nano array 1 to be enhanced, and the substrate 130 in the area is ablated, namely, the periodic structure ablation is generated at the position with the first nano array 1 in a half period dislocation, so as to generate the second nano array 2. Furthermore, the periodic ablation process of the dislocation position is continuously repeated under the subsequent irradiation of incident light, so that the half-period dislocation self-aligned growth of the nano array is realized.

It can be understood that, in the specific pulse overlapping rate range, the motion speed of the displacement table 140, that is, the scanning speed of the laser, can be controlled to realize the self-aligned growth of the periodic nano-arrays with different dimensions, that is, when the middle substrate moves by different preset distances, the periodic nano-unit arrays with different lengths can be generated, thereby realizing the regulation and control of the shapes of the nano-structural units.

In some embodiments, the method of preparing a nanoarray further comprises: the preset distance is within a preset threshold interval.

Specifically, by adjusting the pulse repetition frequency of the laser generated by the laser 110 and the movement speed of the displacement table 140, the pulse overlapping rate of the uniform flat-top line light source on the substrate 130 can be changed, so as to adjust and control the interval between adjacent irradiation paths of the laser, that is, the preset distance. And when the preset distance is smaller than or equal to a preset threshold value, the generated first nano array 1 on the adjacent irradiation path has a guiding effect on the generation of the second nano array 2, namely the second nano array 2 generated subsequently is generated in a self-aligned mode on the second path corresponding to the half-period dislocation of the first nano array 1. When the preset distance is greater than the preset threshold, such automatic matching generation of half-cycle misalignment is no longer present. Different preset thresholds can be selected according to different nano array preparation requirements and laser parameters.

In some embodiments, the laser is a line light source.

It will be appreciated that the line source is a beam of light where the spot focus pattern has a much larger major axis than a minor axis. Meanwhile, other types of linear light sources such as Gaussian linear light sources and the like can achieve similar effects of uniformly preparing the two-dimensional nano array of the flat-top linear light source. Compared with other lasers, the uniform flat top line light source generated by the laser 110 can prepare a corresponding nano array (the first nano array 1 or the second nano array 2) when the first path or the second path is irradiated for a single time, so that the efficiency of nano array preparation is improved, and the efficient nano array preparation is realized.

Referring to fig. 2, in some embodiments, the spot 3 irradiated by the laser along the second path at least partially overlaps the first nanoarray 1.

Specifically, as shown in the shaded portion in fig. 2, the light spot 3 of the uniform flat top line light source has an overlapping portion between the light spot 3 and the first nano array 1, the generated first nano array 1 generates energy redistribution to the incident laser and the surface plasmon wave, and generates the second nano array 2 which is automatically aligned. Therefore, by controlling the degree of overlap of the laser spot 3 with the generated nanoarray, self-aligned growth of the nanoarray of adjacent irradiation paths can be achieved.

In some embodiments, the first nanoarray 1 and the corresponding second nanoarray 2 form a nanoarray set; the nanoarray set includes a plurality of nanosubarrays; the nano array preparation method further comprises the following steps: and controlling the substrate 130 to move a preset distance, and performing the step of controlling the laser 110 to generate the laser again so that the laser irradiates on the substrate 130 to generate the nano array group.

It can be appreciated that after the control substrate 130 moves a predetermined distance, the second nanoarray 2 is generated to be self-aligned with the first nanoarray 1. Taking the second nano array 2 as a generated nano array, moving the substrate 130 by a preset distance, irradiating the substrate 130 by the laser spot 3 along a third path, and interacting the second nano array 2 with incident laser at the moment to redistribute energy on the substrate 130, generating light field enhancement at a position corresponding to the second nano array 2, and generating a third nano array. Continuing to move the substrate 130 according to the preset distance can generate innumerable new-generation nano-arrays corresponding to the generated nano-arrays of the adjacent paths on the substrate 130, and the generated nano-arrays and the new-generation nano-arrays are one nano-array group. The nano arrays in the nano array groups can realize self-alignment generation by controlling the preset distance, and meanwhile, the nano arrays among the nano array groups can also realize self-alignment generation. Then countless nano array groups are generated by the automatic alignment of the present embodiment, and the uniform flat top line light source can prepare a large-area uniform nano array structure on the substrate 130.

By the method for preparing the nano array, the nano array can be prepared in a high-efficiency large area.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention. Furthermore, embodiments of the invention and features of the embodiments may be combined with each other without conflict.

Claims

1. The nano array preparation system is applied to a substrate and is characterized by comprising the following components:

the laser is used for generating laser and generating a first nano array by irradiation on a first path of the substrate;

the controller is connected with the laser;

a displacement table for carrying the substrate;

the laser comprises a beam shaping module, wherein the beam shaping module is used for generating a flat-top line focusing beam;

the controller is also used for controlling the displacement table to move for a preset distance so that the laser irradiates on a second path of the substrate to generate a second nano array; wherein the first nanoarray comprises a plurality of first nanosubarrays and the second nanoarray comprises a plurality of second nanosubarrays;

the adjacent first nanometer subarrays are separated by a first interval, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second interval in the vertical direction of a second path, and the second interval is half of the first interval;

the formed first nano array is used as a uniform nano scattering body, so that interference of excited surface plasmon waves is generated between adjacent sub-arrays of the first nano array, and energy redistribution of surface propagation electromagnetic waves can be realized in second path irradiation;

and (3) at the position of half-period dislocation of the first nano array, the energy distribution of the light field is concentrated due to interference of the excited surface plasmon waves, and a second nano array which is staggered with the first nano array in half-period is formed by ablation, so that the nano array grows in a self-aligned mode.

2. The nanoarray preparation system of claim 1, further comprising:

the imaging device is connected with the laser and is used for collecting images of the substrate processed by the laser;

the controller is further used for calculating the preset distance according to the image, and the controller controls the displacement table to move according to the preset distance.

3. The nanoarray preparation system of claim 2, wherein the imaging device comprises:

the LED light source is used for emitting monochromatic light;

the imaging lens group is connected with the LED light source and used for irradiating the monochromatic light to the substrate and collecting reflected light;

and the CMOS camera is connected with the imaging lens group and used for acquiring the reflected light and generating the image.

4. A method of preparing a nano-array, applied to the nano-array preparation system according to any one of claims 1 to 3, comprising:

controlling the laser to generate laser;

wherein the first nanoarray comprises a plurality of first nanosubarrays and the second nanoarray comprises a plurality of second nanosubarrays;

the adjacent first nanometer subarrays are separated by a first interval, the second nanometer subarrays and the corresponding first nanometer subarrays are separated by a second interval in the vertical direction of a second path, and the second interval is half of the first interval.

5. The method of claim 4, wherein the predetermined distance is within a predetermined threshold interval.

6. The method of claim 4, wherein the laser is a line source.

7. The method of claim 4, wherein the spot irradiated by the laser along the second path at least partially overlaps the first nanoarray.

8. The method of claim 7, wherein the first nanoarray and the corresponding second nanoarray form a nanoarray set; the nano array group comprises a plurality of the first nano subarrays and a plurality of the second nano subarrays; the nano array preparation method further comprises the following steps: