CN114221208A

CN114221208A - Nano-array preparation system and nano-array preparation method

Info

Publication number: CN114221208A
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: 2022-03-22
Anticipated expiration: 2041-11-18
Also published as: CN114221208B

Abstract

The invention discloses a nano-array preparation system and a nano-array preparation method. Wherein, nanometer array preparation system includes: the laser is used for generating laser and irradiating on the first path of the substrate to generate a first nano array; 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 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 nano array and the second nano array are arranged in a staggered manner, 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

Nano-array preparation system and nano-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

As a periodic surface structure, nanoarrays are widely used in various fields due to their special optical properties.

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

Disclosure of Invention

The present invention is directed to solving at least one of the problems of 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 system for preparing a nano-array, applied to a substrate, comprising: the laser is used for generating laser and irradiating on the first path of the substrate to generate a first nano array; a controller 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 further 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; and the adjacent first nano-subarrays are spaced by a first spacing, the second nano-subarrays are spaced by a second spacing from the corresponding first nano-subarrays in the vertical direction of the second path, and the second spacing is half of the first spacing.

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 are regulated and controlled, so that the corresponding nano arrays with different periods, different structure types (dot matrixes or hole matrixes), different orientations and different unit lengths can be generated on the substrate in a scanning mode, and the controllability is realized on the structural characteristics such as the appearance, the length and the orientation of the prepared nano array units. 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 can be realized in the long axis direction of the line light source in single irradiation, and the preparation efficiency and the uniformity of the nano-subarrays are improved. Because the periodic local ablation is carried out by utilizing the excited surface plasmon polariton wave, the size of the prepared nano array is in a sub-wavelength level, and the preparation process is not influenced by diffraction limit and focusing light spots. By regulating and controlling the overlapping rate of the irradiation area of the laser spot, the self-aligned growth of the nano array is realized by utilizing the grating coupling effect and the periodic interference enhancement of the surface wave excited in the preparation process, and the efficient large-area preparation of the nano array is realized without additional complicated splicing and aligning steps when the large-area nano array is prepared.

In some embodiments, the nanoarray production system further comprises: the imaging device is connected with the laser and is used for acquiring an image 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 according to any one of the above embodiments, the method for preparing a nano array comprising:

controlling the laser to generate laser light;

irradiating the first path of the substrate according to the laser to generate a first nano array;

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; and the adjacent first nano-subarrays are spaced by a first spacing, the second nano-subarrays are spaced by a second spacing from the corresponding first nano-subarrays in the vertical direction of the second path, and the second spacing is half of the first spacing.

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, a spot of the laser light irradiating along the second path at least partially overlaps the first nanoarray.

In some embodiments, the first nanoarray and the corresponding second nanoarray form a set of nanoarrays; the set of nanoarrays comprises a plurality of the first array of nanoarrays and a plurality of the second array of nanoarrays; the method for preparing the nano array 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 that the laser irradiates 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 following figures and examples, in which:

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

FIG. 2 is a schematic diagram of a nano-array of the nano-array fabrication system of the present invention;

FIG. 3 is a scanning electron micrograph of a nano-lattice in a nano-array preparation system according to the present invention;

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

FIG. 5 is a flow chart of a method for fabricating 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 conditioning module; 1121. a half-wave plate; 1122. a Glan prism; 113. a beam expanding and collimating module; 1131. a first convex lens; 1132. a first concave lens; 114. a beam shaping module; 1141. a first reflector; 1142. a second reflector; 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 reflector; 123. a beam splitter; 124. a CMOS camera; 130. a substrate; 140. a displacement table; 150. and a controller.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present numbers, and the above, below, within, etc. are understood as including the present numbers. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood 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 otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means 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, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

It should be noted that 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. Among them, the two-dimensional nanoarray is a surface periodic structure constructed of a large number of nano-array units (nano-subarrays) of equal size and equal pitch. However, according to the conventional technology, the induced nano-array structure has difficulty in realizing long-range order characteristics, and the type and uniformity of the nano-structure generated by laser induction have certain limitations. And the nano array generated by laser irradiation is a one-dimensional nano array with limited upper length and size in a light spot irradiation area, namely the nano array generated by laser irradiation has limited area. Meanwhile, the method for inducing the periodic surface structure by the laser depends on periodic ablation caused by interference of surface plasmon waves and incident light, the nano structure obtained by the method is essentially a one-dimensional grating structure, 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 or multi-effect coupling.

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

It is understood that ultrafast laser can irradiate on the surface of the material to generate periodic structure. When the energy density of the incident laser is near or higher than the material damage threshold, the incident laser generates 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 the substrate 130 is irradiated with ultrashort pulse laser energy close to 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 the substrate 130, will cause periodic ablation of the material and generate a stable surface periodic structure. Furthermore, the characteristic size of the local enhanced 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-limited.

Specifically, the laser 110 is used to generate the femtosecond pulsed laser required for the nano-array fabrication of the substrate 130. The laser 110 includes an ultrafast light source 111, an energy adjusting module 112, a beam expanding and collimating module 113, a beam shaping module 114, and a focusing module 116. The ultrafast light source 111 is configured to emit femtosecond linearly polarized pulsed laser with adjustable laser repetition frequency. The energy adjusting module 112 is configured to perform single pulse energy adjustment and control on the femtosecond gaussian linearly polarized pulse laser emitted by the ultrafast light source 111, so as to obtain a gaussian beam with adjustable energy. The gaussian beam is an electromagnetic wave 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 glan prism 1122. Because a large number of photons of the pulse laser are emitted in a very small time range in a concentrated manner, the energy density is very high, and the output power is high; by calculating the average power P (i.e. the amount of energy consumed per unit time) of the pulsed laser during a period of operation, and the repetition frequency f (i.e. the number of laser pulses emitted per unit time) of the pulsed laser, the energy per pulse J can be obtained by the following calculation formula:

the gaussian beam spot after energy modulation is expanded and collimated by the beam expanding and collimating module 113, and an expanded and collimated spot is obtained. The beam expanding and collimating module 113 includes a first concave lens 1132 and a first convex lens 1131. The beam expanding and collimating module 113 can change the diameter and the 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 a gaussian beam is changed into 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 expanding and collimating module 113 can improve the beam collimation characteristics and the spot focusing degree. The expanded beam collimated light spot is emitted from the beam expanding and 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 polarizing plate 1146. The beam shaping module 114 can obtain a flat-topped light spot with uniform energy distribution, steep boundary and a specific shape. After the expanded collimated light spots are homogenized by the beam shaping module 114, the energy distribution of the light spots is uniform, and the incident Gaussian beam is shaped into a flat-top beam. The flat-topped beam has almost uniform energy density over a certain area within its propagation cross-section. After passing through the polarizer 1146 in the beam shaping module 114, the linearly polarized flat-top beam is modulated in polarization, and the polarization angle of the linearly polarized flat-top beam can be obtained by adjusting the angle of the polarizer 1146 according to actual needs. The expanded and collimated gaussian beam can obtain a linearly polarized flat-topped beam in a specific polarization state after passing through the beam shaping module 114.

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

As can be understood, the ultrafast light source 111 emits femtosecond gaussian linearly polarized pulse laser, the gaussian beam sequentially passes through the energy adjustment module 112 composed of the half-wave plate 1121 and the glan prism 1122 to perform laser energy adjustment, and further performs laser beam expansion through the beam expansion collimation module 113 composed of the first convex lens 1131 and the first concave lens 1132; the expanded beam 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 polarizing film 1146 through a first reflecting mirror 1141, so that generation of linear polarization flat-top beams is realized; and then reflected by the dichroic mirror 115 to enter the lenticular lens 1161. The modulated flat-top light beam enters the cylindrical convex lens 1161 focusing module 116 to obtain a uniform flat-top light source with a specific polarization state. Finally, the laser 110 outputs a uniform flat-top line light source with specific energy, polarization state and wavelength. 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 from the lenticular lens 1161 to 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 the preparation of the nano array on the surface of the substrate 130 by the uniform flat-top line light source.

It can be understood that the nano-array structure is prepared on the substrate 130 in the present embodiment by the method of generating the laser-induced surface periodic structure by the uniform flat-top line light source irradiation generated by the laser 110. Specifically, the light spots 3 (i.e., the shaded portions in fig. 2) of the uniform flat top line light source are focused on a first path of the substrate 130, and meanwhile, the polarization of incident light is parallel to the long axis direction of the light spots, so that the laser light spots 3 of the uniform flat top line light source generate first nano arrays 1 which are uniformly arranged on the first path of the substrate 130, and the first nano arrays 1 are generated along the long axis direction of the light spots 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. Then, the pulse repetition frequency of the laser generated by the laser 110 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 laser spot 3 on the second path is indirectly controlled, after the substrate 130 moves a preset distance along the short axis direction of the uniform flat-top line light source, the laser spot 3 is focused on the second path of the substrate 130, and the second nano array 2 is generated by irradiation. Subarrays in the irradiation areas of the laser spots 3 on different paths are independently generated, namely the subarrays among different scanning paths lack an effective coupling mechanism to cause random generation positions, so that the nanoarrays generated on the first path and the second path irradiated by different lasers are generated in a non-aligned mode, namely the first nanoarray 1 and the second nanoarray 2 are not uniformly arranged, and therefore the structure prepared by the method is disordered in a long-range mode. In the embodiment, the substrate 130 is controlled to move for a preset distance, so that the light spots 3 of the uniform flat-top line light source are focused on the second path of the substrate 130, meanwhile, the uniform flat-top line light source light spots 3 on the second path cover part of the generated first nano array 1 on the first path, the formed first nano array is used as a uniform nano scatterer, and then interference of exciting surface plasmon waves is generated between adjacent sub arrays of the first nano array, and energy redistribution of surface-propagated electromagnetic waves can be realized in subsequent irradiation of the second path. Since the first nano-array 1 is an existing structure on the surface of the substrate 130, under the radiation of the incident laser, the first nano-array 1 enables the uniform periodic directional distribution of the energy for generating the second nano-array 2. In the position of the first nano array 1 with half-period dislocation, because the surface plasmon wave is excited to cause the concentration of optical field energy distribution, a second nano array which presents half-period dislocation with the first nano array 1 is formed by ablation, so that the nano array grows in a self-alignment way. The preset distance is the distance between a first path of the uniform flat top line light source generating first nano array 1 and a second path of the uniform flat top line light source generating second nano array 2.

It will be appreciated that due to the energy redistribution 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 the second nanoarray 2 will be ablated. Specifically, the second nano-subarray generated by self-alignment is misaligned with the corresponding first nano-subarray by a half period, that is, the subsequently generated second nano-subarray is generated by self-alignment on the second path of laser irradiation on the extension line of the distance central line of the adjacent first nano-subarray.

It can be understood that, in the self-aligned growth process of the two-dimensional array, due to the grating coupling effect and the interference enhancement of the surface plasmon waves, the self-aligned characteristic of the grown nano-unit array has robustness, that is, the local structural disorder caused by the chip or the surface defect of the substrate in the processing process can be gradually corrected in the self-aligned growth process 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, the wavelength, the single pulse energy of the laser emitted by the ultrafast light source 111, and the moving speed of the displacement stage 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 arrays, and the transverse arrangement direction (the direction of the first path) of the plurality of first nano arrays is parallel to the uniform flat-top line light source. Wherein, the plurality of first nano-array and the adjacent first nano-array are all equal in the first path direction, and the pitch 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-arrays uniformly arranged at intervals of the period 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. By regulating and controlling the wavelength of the emergent laser, namely the wavelength of the light of the uniform flat-top line light source, the nano arrays with different spacing distributions (different periods) can be obtained. In addition, the period for preparing the nano array can be further regulated and controlled by changing the incident angle between the incident light and the surface of the substrate 130 and the processing environment medium, such as preparation in liquid. Specifically, the structure type of the nano-array formed by ablation can be controlled by controlling the single-pulse energy J of the processing laser through controlling the energy adjusting module 112 in the laser 110. In the process of preparing the nano array, different energy excitation can cause different energy distribution, and finally the nano lattice array or the nano hole array is formed. As shown in fig. 3 and 4, the substrate 130 in fig. 3 has a convex nano-lattice, and the substrate 130 in fig. 4 has a concave nano-pore lattice. For example, when the laser pulse repetition frequency is 1kHz and the laser single pulse energy is 2.37 μ J, i.e., low energy excitation, the surface plasmon excitation is weak, and thus the incident light energy (the long axis direction of the spot 3) and the surface plasmon wave (the short axis direction of the spot 3) will cause ablation together, thereby producing the nano-lattice array. When the laser single pulse energy is 2.66 muj, i.e. high energy excitation, the surface plasmon wave excitation is extremely strong, and the incident light field energy is concentrated to the position in the circle in fig. 2, finally resulting in the generation of the nanopore array.

Specifically, the polarization direction of the generated uniform flat-top line light source is changed by adjusting the direction of the polarizer 1146 of the beam shaping module 114 in the laser 110, and the direction of the uniform flat-top line light source scanning on the substrate 130 (the long axis direction of the uniform flat-top line light source) is combined. The orientation of the nano-subarray in the nano-array structure can be regulated and controlled by controlling the change of an 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 from 0 degree to 90 degrees.

Specifically, by regulating and controlling the movement speed of the displacement stage 140, i.e., the scanning speed of the uniform flat-top line light source scanning substrate 130, the pulse separation distance of the light spot 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, i.e., control the morphology of the nano-subarray, for example, prepare a circular, quasi-circular or elongated nano-subarray, or even a mixed structure of circular, quasi-circular and elongated.

Specifically, the control substrate 130 is moved by a predetermined distance by controlling the repetition frequency f of the pulsed laser emitted from the laser 110 and the movement speed of the displacement stage 140. The displacement stage 140 is controlled by the controller 150 to move at a constant speed, 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 repetition rate of laser pulses is 1kHz, the energy of a single laser pulse is 2.1 muJ to 3.1 muJ, and the moving speed of the stage 140, i.e., the moving speed of the substrate 130, is 0.4mm/s to 1mm/s, thereby controlling the overlap rate N of the laser pulses. The overlapping rate of the laser pulses represents the preset distance between different paths of the substrate 130, and the overlapping rate of the laser pulses can be obtained by the following calculation formula:

where d is the size of the spot 3 of the processing laser (i.e., the uniform flat-top line light source in this embodiment), and v is the moving speed of the stage 140. In the embodiment, by controlling the pulse overlapping rate 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 can redistribute and regulate the electromagnetic field of the subsequent incident laser on the surface of the material, and an optical enhancement effect of half-cycle dislocation relative to the formed nano array structure is generated. Thereby causing ablation of the half-cycle misalignment relative to the generated structure, i.e., the second nanoarray is generated in a half-cycle misaligned alignment with the corresponding generated first nanoarray on the second path. Thereby producing a honeycomb-like distribution of nano-array structures as described in fig. 2 to 4. For different nano-array preparation requirements, different sizes of the light spots 3, different laser wavelengths, different laser single pulse energy sizes and different scanning speeds (the movement speed of the substrate 130) need to be adopted, and the pulse overlapping rate N also needs to be adjusted correspondingly. For this reason, the present embodiment is not described in detail herein.

It can be understood that, in the embodiment, when the uniform flat-top line light source generated by the laser 110 is irradiated on the first path or other paths, the nano-subarrays uniformly arranged on the paths can be prepared through a single irradiation. And the pulse overlapping rate of the emergent laser is controlled, namely the distance (preset distance) between the irradiation paths of the uniform flat-top line light source is regulated and controlled, so that the light field energy enhancement can be generated on the irradiation paths irradiated by the laser at the corresponding positions of the adjacent generated nano arrays, the nano arrays with staggered half cycles can be generated on the laser irradiation paths in a self-aligning manner, and the large-area uniform preparation of the two-dimensional nano arrays can be realized. The nano array can be prepared by combining the uniform flat-top line light source with single scanning, and the efficient large-area preparation of the uniform nano array can be realized.

According to the embodiment of the application, by 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 matrixes or hole matrixes), different orientations and different unit lengths can be generated on the substrate 130 in a scanning manner, and the controllability is realized on the structural characteristics of the prepared nano array units, such as the appearance, the length and the orientation. Meanwhile, the uniform flat-top line light source is used for scanning, so that the preparation efficiency and the uniformity of the nano-subarray are improved. Because the size of the prepared nano array is in a sub-wavelength level, the preparation process is not influenced by diffraction limit and focusing light spots. By regulating and controlling the overlapping rate of laser spots and utilizing the grating coupling effect and the surface wave periodic interference enhancement of the uniform linear light source excited on the surface of the uniform nano array in the preparation process, the uniform periodic uniform light field on the surface of the substrate is enhanced, the self-aligned growth of the nano array is further realized, no additional complex splicing alignment step is needed when the large-area nano array is prepared, and the high-efficiency large-area preparation of the nano array is realized.

Referring again to fig. 1, in some embodiments, the nano-array fabrication system 100 further includes: the imaging device 120 is connected with the laser 110 and is used for acquiring 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 acquire an image of the substrate 130 processed by the laser. 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 substrate 130 in the processing process, the relative position of the cylindrical convex lens 1161 and the surface of the substrate 130 can be further adjusted through the image information, so that the focal point of the light spot 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, configured to irradiate the monochromatic light onto the substrate 130, and collect reflected light; and the CMOS camera 124 is connected with the imaging lens group and is used 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, monochromatic light emitted by the LED light source 121 is reflected by the beam splitter 123, sequentially passes through the dichroic mirror 115 and the focusing objective lens to reach the surface area of the substrate 130, then is transmitted along an incident path, sequentially passes through the focusing objective lens, the dichroic mirror 115 and the beam splitter 123, and finally enters the CMOS camera 124 through the third reflector 122 for imaging, so that the real-time observation of the condition of preparing the nano array by using 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 invention provides a method for fabricating a nano-array, which is applied to the nano-array fabrication system 100 according to any one of the above embodiments, including:

s101, controlling a laser to generate laser;

and S102, controlling the displacement table to move for a preset distance.

The laser is used for irradiating on the first path of the substrate 130 to generate a first nano array 1; 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; and the adjacent first nano-subarrays are separated by a first spacing, the second nano-subarrays are separated from the corresponding first nano-subarrays by a second spacing in the direction of the second path, and the second spacing is half of the first spacing.

It is understood that the laser 110 generates a uniform flat-top line light source with adjustable laser parameters, which is irradiated on the processed substrate 130 to scan to generate the nano-array. By regulating and controlling the movement speed of the displacement table 140 and the laser repetition frequency of the laser 110, the size of the interval between the adjacent irradiation paths of the uniform flat-top line light source, that is, the size of the preset distance, can be changed, so that the energy of the incident laser and the surface plasmon excited by the surface of the substrate 130 is redistributed, and the light field enhancement is generated on the generated second path with the 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 nanoarrays is achieved.

Specifically, the corresponding moving speed of the stage 140 may be set according to different laser parameters and the type of the nano-array structure to be generated. 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 muJ, the minor axis size of a light spot 3 is 2.1μm, the laser pulse repetition frequency is 1kHz, the substrate movement speed is 0.4-1mm/s, namely when the pulse overlapping rate is not less than 2.1 and not more than 5.25, the uniform nanopore array is generated.

It is understood that, as shown in fig. 2, a uniform flat-top line light source is irradiated on the substrate 130 and the first nano-array 1 is generated, 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 range, the incident laser can support excitation of sufficient carrier concentration to generate surface plasmon waves to achieve 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 a part of the first nano array 1 in the first path, and 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 incident light energy, that is, through surface plasmon interference of adjacent structures, energy generation enhancement is generated in the middle of the adjacent nano array of the first nano array 1 and causes ablation of the substrate 130 in the area, that is, periodic structure ablation is generated at a position staggered with a half period of the first nano array 1, so as to generate the second nano array 2. Furthermore, under the irradiation of subsequent incident light, the periodic ablation process of the dislocation position is continuously repeated, so that the half-period dislocation self-alignment growth of the nano array is realized.

It can be understood that, within the above specific range of pulse overlapping rate, the movement speed of the displacement stage 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 size degrees, that is, when the middle substrate moves for 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-structure units.

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

Specifically, the pulse overlapping rate of the uniform flat-top line light source on the substrate 130 can be changed by adjusting the pulse repetition frequency of the laser generated by the laser 110 and the movement speed of the displacement table 140, so as to adjust the interval between adjacent irradiation paths of the laser, i.e., the preset distance. By regulating and controlling the size of the preset distance, when the preset distance is smaller than or equal to the preset threshold, 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 subsequently generated second nano array 2 is generated in a self-aligning manner 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 no longer exists. 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 whose spot focuses a beam whose long axis is much larger than its short axis. Meanwhile, other linear light sources such as Gaussian linear light sources can achieve similar effects of uniform preparation of 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 once, so that the preparation efficiency of the nano array is improved, and the efficient preparation of the nano array is realized.

Referring to fig. 2, in some embodiments, the laser irradiates a spot 3 along the second path to at least partially overlap with the first nano-array 1.

Specifically, as shown by a shaded portion in fig. 2, a light spot 3 of the uniform flat-top line light source is overlapped with the first nano array 1, and the generated first nano array 1 redistributes energy of the incident laser and the surface plasmon wave, and generates the automatically aligned second nano array 2. Therefore, by controlling the overlapping degree of the laser spot 3 and the generated nano array, the self-aligned growth of the nano array of the adjacent irradiation paths can be realized.

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

It is understood that the second nano-array 2 is self-aligned with the first nano-array 1 after the control substrate 130 moves a predetermined distance. And moving the substrate 130 by a preset distance with the second nano array 2 as the generated nano array, irradiating the substrate 130 by the laser spot 3 along a third path, and enabling the second nano array 2 to interact with incident laser at the moment, so that energy on the substrate 130 is redistributed, an optical field enhancement is generated at a position corresponding to the second nano array 2, and a third nano array is generated. By moving the substrate 130 according to the predetermined distance, a plurality of newly generated nano-arrays corresponding to the generated nano-arrays of the adjacent paths can be generated on the substrate 130, and the generated nano-arrays and the newly generated nano-arrays form a nano-array group. The nano arrays in the nano array groups are generated in a self-aligning mode by controlling a preset distance, and meanwhile, the nano arrays among the nano array groups can also be generated in a self-aligning mode. Then, by using the present embodiment to automatically align and generate a plurality of nano-array groups, the uniform flat-top line light source can produce a large-area uniform nano-array structure on the substrate 130.

By the method for preparing the nano array, the efficient large-area preparation of the nano array can be realized.

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 those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the 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 laser is used for generating laser and irradiating on the first path of the substrate to generate a first nano array;

a controller 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 further 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;

and the adjacent first nano-subarrays are spaced by a first spacing, the second nano-subarrays are spaced by a second spacing from the corresponding first nano-subarrays in the vertical direction of the second path, and the second spacing is half of the first spacing.

2. The system for fabricating nanoarrays according to claim 1, further comprising:

the imaging device is connected with the laser and is used for acquiring an image 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 production 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 for preparing a nano array, applied to the nano array preparation system according to any one of claims 1 to 3, wherein the method for preparing a nano array comprises:

controlling the laser to generate laser light;

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

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 light source.

7. The method of claim 4, wherein the laser irradiates a spot along the second path that at least partially overlaps the first nano-array.

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