CN110501892B - Method and device for preparing chiral multi-lobe microstructure - Google Patents

Abstract

The invention provides a preparation method and a device of a chiral multi-petal microstructure, belonging to the technical field of micro-nano manufacturing. The preparation method of the chiral multi-lobe microstructure comprises the following steps: calculating a hologram of the chiral multi-lobed microstructure; processing the photoresist material sample by using a femtosecond holographic processing system according to the hologram to obtain a chiral multi-petal microstructure sample to be developed; placing the chiral multi-petal microstructure sample to be developed into a developing solution for development to obtain a discrete externally-expanded chiral multi-petal microstructure; and after the discrete externally-expanded chiral multi-petal microstructure is taken out from the developing solution, the discrete externally-expanded chiral multi-petal microstructure is drawn inwards under the action of the capillary force of the developing solution remained on the surface, so that the discrete or assembled chiral multi-petal microstructure is obtained. According to the method and the device for preparing the chiral multi-lobe microstructure, provided by the invention, the femtosecond laser holographic high-efficiency processing technology and the capillary force driven self-assembly technology are combined, the preparation of the three-dimensional chiral multi-lobe microstructure can be flexibly and rapidly realized, and the processing efficiency is improved.

Description

Preparation method and device of chiral multi-lobed microstructure

technical field

The invention relates to the technical field of micro-nano manufacturing, in particular to a preparation method and device of a chiral multi-lobed microstructure.

Background technique

Chirality, which represents a symmetrical property of an object. A chiral structure means that the structure cannot be rotated or translated exactly to its mirror image. There are many chiral structures in nature, such as amino acids, DNA molecules, hands, shells, spiral galaxies and so on. Chiral structures are also widely used in daily life, such as screws, coil springs, spiral stairs, spiral blades, spiral shafts, and so on. At the micro-nano scale, chiral structures have unique optical response characteristics, and the rapid preparation of diverse chiral micro-nano structures is the cornerstone of studying their optical properties.

With the development of micro-nano processing methods, chiral micro-nano structures are more and more convenient to prepare. At present, the processing methods of chiral micro-nano structures can be divided into two categories, namely top-down processing technology and bottom-up assembly technology. For top-to-bottom processing technologies, femtosecond laser direct writing, lithography, focused ion beam etching, electron beam lithography, etc. are common. Relatively speaking, femtosecond laser direct writing has the unique advantages of true three-dimensional processing and is an ideal method for processing chiral micro-nano structures. However, femtosecond laser direct writing requires a single-focus scanning strategy, so the processing efficiency is low and needs to be overcome. For bottom-up assembly technology, the main principle is to use chiral materials to induce the formation of chiral micro-nano structures in a liquid environment. The disadvantage of this type of technology is that the prepared chiral structures can only be attached to chiral materials. However, it is difficult to obtain the desired hand-shaped structural monomer, and its morphology cannot be freely controlled.

The preparation of conventional chiral micro-nano structures is generally achieved by using top-down processing technology or bottom-up assembly technology. can not be arbitrarily controlled. Therefore, by combining the above two methods at the same time, an efficient preparation method of multi-lobed, controllable chirality, variable structural size, and variable structural shape of diverse chiral micro-nano structures is realized. features are significant.

SUMMARY OF THE INVENTION

(1) Technical problems to be solved

The present invention provides a method and device for preparing a chiral multi-lobed microstructure to at least partially solve the above technical problems.

(2) Technical solutions

According to one aspect of the present invention, there is provided a method for preparing a chiral multi-lobed microstructure, the method comprising:

Calculate holograms of chiral multi-lobed microstructures;

According to the hologram, use a femtosecond holographic processing system to process the photoresist material sample to obtain a chiral multi-lobed microstructure sample to be developed;

Putting the chiral multi-lobed microstructure sample to be developed into a developing solution for development to obtain a discrete and outwardly expanded chiral multi-lobed microstructure;

After the discrete and outwardly expanding chiral multi-lobed microstructures are taken out from the developing solution, they are closed inward by the capillary force of the developing solution remaining on the surface to obtain discrete or assembled chiral multi-lobed microstructures.

In some embodiments, computing a hologram of a chiral multi-lobed microstructure includes:

Set the pixel size of the square hologram of the chiral multi-lobe microstructure, perform grid division on the square hologram, define the pixel coordinates of each point on the square hologram, and initialize the total phase value of each pixel point ;

According to the pixel size of the square hologram and the circular spot characteristics of the femtosecond laser beam, an outer circular mask with a suitable radius is added to shield the invalid area outside the circular mask to obtain a circular hologram;

Add a central regular polygon mask figure to the circular hologram according to the principle of discrete superposition; calculate the phase value of any point outside the central regular polygon mask figure; convert the phase value into a gray value, and generate all the A hologram of the described chiral multi-lobed microstructure.

In some embodiments, calculating the phase value of any point outside the central regular polygon mask pattern, including:

Select any vertex of the central regular polygon mask graphic as a starting reference point;

Calculate the pixel distance between any point outside the central regular polygon mask graphic and the starting reference point;

Using the pixel distance, calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the starting reference point;

According to the azimuth angle, calculate the phase value of any point outside the central regular polygon mask pattern relative to the starting reference point, and accumulate the phase value to the total phase value;

Update the starting reference point at a preset step to obtain a new reference point, and recalculate the phase value of any point outside the central regular polygon mask graphic relative to the new reference point according to the new reference point , accumulate it to the total phase value; repeat this step until the new reference point returns to the starting reference point, then the total phase value obtained is the outside of the central regular polygon mask figure Phase value at any point.

In some embodiments, according to the azimuth angle, calculating the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point, including:

If any point outside the central regular polygon mask graphic is located on the left side of the reference point, use the first calculation formula to calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point;

If any point outside the central regular polygon mask figure is located on the right side of the reference point, the second calculation formula is used to calculate the azimuth angle of any point outside the central regular polygon mask figure relative to the reference point.

In some embodiments, after the discrete outwardly expanding chiral multi-lobed microstructure is subjected to the capillary force of the developer, a discrete or assembled chiral multi-lobed microstructure is obtained, including:

When the height of the discretely expanded chiral multi-lobed microstructure is higher than a preset height, the discretely expanded chiral multi-lobed microstructure is subjected to the capillary force of the developer to obtain an assembled hand. Sexual multi-lobed microstructure;

When the height of the discretely expanded chiral multi-lobed microstructure is lower than a preset height, the discretely expanded chiral multi-lobed microstructure is still in a discrete state after being acted by the capillary force of the developer. Chiral multi-lobed microstructures.

According to another aspect of the present invention, there is provided a device for preparing a chiral multi-lobed microstructure, the device comprising:

The hologram calculation unit is used to calculate the hologram of the chiral multi-lobed microstructure;

a first acquisition unit, configured to process a photoresist material sample using a femtosecond holographic processing system according to the hologram to obtain a chiral multi-lobe microstructure sample to be developed;

The second acquisition unit is used to put the chiral multi-lobed microstructure sample to be developed into a developing solution for development, and obtain a discrete and outwardly expanded chiral multi-lobed microstructure;

The third acquisition unit, after the discrete and outwardly expanding chiral multi-lobed microstructures are taken out from the developing solution, they are closed inward by the capillary force of the developing solution remaining on the surface to obtain discrete or assembled chirality Multi-lobed microstructure.

In some embodiments, the hologram computing unit includes:

The first setting subunit is used to set the pixel size of the square hologram of the chiral multi-lobe microstructure, perform grid division on the square hologram, define the pixel coordinates of each point on the square hologram, and initialize each point. The total phase value of the pixel point;

The second setting subunit is used for adding an outer circular mask with a preset radius according to the pixel size of the square hologram and the circular spot characteristics of the femtosecond laser beam, and shielding the invalid area outside the circular mask to obtain circular hologram;

a mask pattern acquiring subunit, adding a central regular polygon mask pattern on the circular hologram according to the discrete superposition principle;

a phase value calculation subunit, used to calculate the phase value of any point outside the central regular polygon mask figure;

The hologram acquisition sub-unit is used for converting the phase value into a gray value and generating a hologram of the chiral multi-lobed microstructure.

In some embodiments, the phase value calculation subunit includes: a reference point selection subunit, configured to select any vertex of the central regular polygon mask graph as a starting reference point;

a pixel distance calculation subunit, used to calculate the pixel distance between any point outside the central regular polygon mask figure and the starting reference point;

an azimuth angle calculation subunit, used to calculate the azimuth angle of any point outside the central regular polygon mask figure relative to the starting reference point;

In some embodiments, the azimuth angle calculation subunit includes:

The left side azimuth angle calculation unit is used to calculate, if any point outside the central regular polygon mask figure is located on the left side of the reference point, using the first calculation formula to calculate the relative relationship between any point outside the central regular polygon mask figure relative to the reference point. the azimuth of the reference point;

The right side azimuth angle calculation unit is used to calculate the relative position of any point outside the central regular polygon mask graphic relative to the The azimuth of the reference point.

a phase value calculation subunit, configured to calculate the phase value of any point outside the central regular polygon mask figure relative to the starting reference point according to the azimuth angle, and accumulate the phase value to the total phase value;

The phase value acquisition sub-unit updates the starting reference point at a preset step to obtain a new reference point, and recalculates the relative relationship between any point outside the central regular polygon mask graph according to the new reference point relative to the new reference point. The phase value of the reference point is accumulated to the total phase value; this step is repeated until the new reference point returns to the starting reference point, then the total phase value obtained is the central regular polygon Phase value at any point outside the mask pattern.

In some embodiments, the third obtaining unit includes:

The assembled state acquisition subunit is used for, when the height of the discretely expanded chiral multi-lobed microstructure is higher than a preset height, the discrete and expanded chiral multi-lobed microstructure passes through the capillary force of the developer After the action, an assembled chiral multi-lobed microstructure is obtained;

The discrete state acquisition subunit is used for, when the height of the discretely expanded chiral multi-lobed microstructure is lower than a preset height, the discrete expanded chiral multi-lobed microstructure passes through the capillary force of the developer After the action, it is still a discrete chiral multi-lobed microstructure.

(3) Beneficial effects

As can be seen from the above technical solutions, the preparation method and device of the chiral multi-lobed microstructure of the present invention have at least one or a part of the following beneficial effects:

(1) The method and device for preparing a chiral multi-lobe microstructure provided by the present invention combine the femtosecond laser holography high-efficiency processing technology with the capillary force-driven self-assembly technology, which can flexibly and quickly realize the preparation of a three-dimensional chiral multi-lobe microstructure , improve the processing efficiency.

(2) The preparation method and device of the chiral multi-lobed microstructure provided by the present invention can control the number of petals of the chiral multi-lobed microstructure by changing the shape of the central mask of the hologram; by changing the positive and negative of the topological charge number of the hologram , the left and right chiral structures can be processed; by controlling the number of superpositions of the hologram, that is, the number of topological charges, the lateral size of the chiral structure can be controlled; by controlling the exposure depth, the vertical size of the chiral structure can be controlled.

(3) The preparation method and device of the chiral multi-lobed microstructure provided by the present invention can control the shape of the chiral structure after being driven by capillary force to be discrete or assembled by controlling the longitudinal dimension, that is, the height of the chiral multi-lobed microstructure. state.

Description of drawings

Fig. 1 is the flow chart of the preparation method of the chiral multi-lobed microstructure provided in the embodiment of the present invention;

2A-2F are the hologram generation process of the chiral three-lobed microstructure provided by the embodiment of the present invention;

3A is a hologram of partial topological charge numbers under the mask with different circumscribed circle radii in an equilateral triangle mask (N=3) provided by an embodiment of the present invention;

3B is a hologram of a regular quadrilateral mask (N=4), a regular pentagon mask (N=5), and a regular hexagonal mask (N=6) provided by an embodiment of the present invention;

4 is a schematic diagram of a femtosecond holography processing system provided by an embodiment of the present invention;

5A is a simulation diagram of the light field of the hologram at different positions behind the lens 11 (f=600mm) in the processing system of FIG. 3 when the equilateral triangular mask (N=3) is provided in the embodiment of the present invention;

5B is a light field simulation of a regular quadrilateral mask (N=4), a regular pentagonal mask (N=5), and a regular hexagonal mask (N=6) provided at the focal point of the lens 11 according to the embodiment of the present invention picture;

6A is an electron microscope diagram of a processing structure of an equilateral triangular mask (N=3) provided by an embodiment of the present invention, including different sizes and shapes;

6B is an electron microscope diagram of a processing structure of a regular quadrilateral mask (N=4), a regular pentagon mask (N=5), and a regular hexagonal mask (N=6) provided by an embodiment of the present invention;

FIG. 7 is a structural diagram of a device for preparing a chiral multi-lobed microstructure according to an embodiment of the present invention.

In the above drawings, the meanings of the reference numerals are as follows:

1-laser; 2-half-wave plate; 3-polarization beam splitter prism; 4,5-lens; 6-shutter; 7-attenuator; 8-high reflection lens; 9-spatial light modulator; 10,12-lens ; 11-diaphragm; 13-reflector; 14-oil mirror; 15-voltage station; 16-photoresist sample; 17-halogen lamp; 18-CCD; 19-computer.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

According to one aspect of the present invention, there is provided a method for preparing a chiral multi-lobed microstructure, as shown in FIG. 1 , the method includes:

S11, calculate the hologram of the chiral multi-lobed microstructure;

S12, according to the hologram, use a femtosecond holographic processing system to process the photoresist material sample according to the hologram to obtain a chiral multi-lobed microstructure sample to be developed;

S13, putting the chiral multi-lobed microstructure sample to be developed into a liquid developing solution for development to obtain a discrete and outwardly expanded chiral multi-lobed microstructure;

S14 , after the discrete and outwardly expanded chiral multi-lobed microstructures are taken out from the developing solution, the chiral multi-lobed microstructures in a discrete state or an assembled state are obtained after the capillary force of the remaining developing solution on the surface is applied.

The preparation method of the chiral multi-lobed microstructure provided by the present invention combines the femtosecond laser holography high-efficiency processing technology and the capillary force-driven self-assembly technology, which can flexibly and quickly realize the preparation of the three-dimensional chiral multi-lobed microstructure, and improves the processing speed. efficiency.

In this embodiment, step S11 specifically includes the following sub-steps:

Set the pixel size of the square hologram of the chiral multi-lobe microstructure, divide the square hologram into grids, define the pixel coordinates of each point on the square hologram, and initialize the total phase value of each pixel point;

According to the pixel size of the square hologram and the circular spot characteristics of the femtosecond laser beam, an outer circular mask with a preset radius is added to shield the invalid area outside the circular mask to obtain a circular hologram;

Add a central regular polygon mask pattern on the circular hologram according to the principle of discrete superposition; wherein, the size of the central regular polygon mask is controlled by its circumscribed circle radius, and the coverage area of the central regular polygon mask is also shielded;

Calculate the phase value of any point outside the central regular polygon mask figure;

Convert phase values to grayscale values and generate holograms of chiral multilobed microstructures.

Among them, the phase value of any point outside the mask pattern is calculated, including:

利用像素距离，计算中心正多边形掩膜图形外部任一点相对于起始参考点的方位角：若中心正多边形掩膜图形任一点位于起始参考点的左侧，采用第一计算公式theta＝arccos(j-y0)/r]计算掩膜图形外部任一点相对于起始参考点的方位角；若中心正多边形掩膜图形外部任一点位于起始参考点的右侧，采用第二计算公式theta＝2冗-arccos[(j-y0)/r]计算掩膜图形外部任一点相对于所述参考点的方位角，其中，j为所述中心正多边形掩膜图形外部任一点的纵坐标，y0为所述起始参考点的纵坐标，r为所述中心正多边形掩膜图形外部任一点与起始参考点的像素距离；按预设步距更新起始参考点得到新的参考点，并根据新的参考点重新计算中心正多边形掩膜图形外部任一点相对于新的参考点的相位值，将其累计到总相位值；循环此步骤，直到新的参考点返回到起始参考点，则得到的总相位值即为中心正多边形掩膜图形外部任一点的相位值。Select any vertex of the central regular polygon mask graphic as the starting reference point; calculate the pixel distance between any point outside the central regular polygon mask graphic and the starting reference point

Using the pixel distance, calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the starting reference point: if any point on the central regular polygon mask graphic is located on the left side of the starting reference point, the first calculation formula theta=arccos is used. (j-y0)/r] Calculate the azimuth angle of any point outside the mask graphic relative to the starting reference point; if any point outside the central regular polygon mask graphic is located on the right side of the starting reference point, the second calculation formula theta is used =2×-arccos[(j-y0)/r] Calculate the azimuth angle of any point outside the mask figure relative to the reference point, where j is the ordinate of any point outside the central regular polygon mask figure, y0 is the ordinate of the starting reference point, r is the pixel distance between any point outside the central regular polygon mask graphic and the starting reference point; update the starting reference point by the preset step distance to obtain a new reference point, And recalculate the phase value of any point outside the central regular polygon mask graph relative to the new reference point according to the new reference point, and accumulate it to the total phase value; this step is repeated until the new reference point returns to the starting reference point , then the total phase value obtained is the phase value of any point outside the central regular polygon mask figure.

In the preparation method of the chiral multi-lobed microstructure provided by the present invention, the number of petals of the chiral multi-lobed microstructure is controlled by changing the shape of the central mask of the hologram; by changing the positive and negative of the topological charge number of the hologram, left, Processing of the right chiral structure; by controlling the number of superpositions of the hologram, that is, the number of topological charges, the lateral size of the chiral structure can be controlled; by controlling the exposure depth, the vertical size of the chiral structure can be controlled.

In this embodiment, step S14 specifically includes:

When the height of the discretely expanded chiral multi-lobed microstructure is higher than the preset height, the assembled chiral multi-lobed microstructure is obtained after the capillary force of the developing solution is applied to the discretely expanded chiral multi-lobed microstructure;

When the height of the discretely expanded chiral multi-lobed microstructure is lower than the preset height, the discretely expanded chiral multi-lobed microstructure is still a discrete chiral multi-lobed microstructure after the capillary force of the developer. .

The preparation method of the chiral multi-lobed microstructure provided by the present invention can control the shape of the chiral structure driven by capillary force to be discrete or assembled by controlling the longitudinal dimension, that is, the height of the chiral multi-lobed microstructure.

In a specific embodiment, the generation diagram of the calculation process of the central equilateral triangle mask hologram of the three-lobed chiral microstructure is shown in Figures 2A-2F, and the calculation process is:

1) Set the size of the hologram to 1080*1080 (unit: pixel), that is, the horizontal size column=1080, the vertical size row=1080, and the grid is divided by the built-in function meshgrid of Matlab, with the lower left corner as the starting point, and the coordinates are (0, 0), the upper right corner is the end point, the coordinates are (1080, 1080), the center coordinates are (540, 540), and the coordinates of the mesh vertices are marked as (i, j), i, j ∈ (0, 1080), and then use phase1(i, j)=0, i, j∈(0, 1080) zeros the initial phase position of each point of the hologram, thereby generating the background grid of the hologram, as shown in Figure 2A;

2) Since the light spot of the femtosecond laser is a circular Gaussian light spot, the effective use part of the hologram background in Figure 2A is the inner part of the circle with the center coordinate as (540, 540) and the radius R=540, and the outer part of the circle passes through. The mask mask1(i, j)=0 shields the phase and displays it in black, as shown in Figure 2B;

然后通过掩膜mask2(i，j)＝0屏蔽三角形内部区域相位，显示为黑色；3) Set the coordinate value of the center pixel of the mask pattern to (540, 540), corresponding to the center pixel coordinate of the spatial light modulator (1080*1080), and the radius of the circumcircle of the mask pattern to be r ₀ . Combined with the size of the hologram, select r ₀ ∈ (200, 500) is more suitable, and the shape of the mask can be regular triangle, regular quadrilateral, regular pentagon, regular hexagon, corresponding to the processing of 3-lobed, 4-lobed, 5-lobed, and 6-lobed chiral structures, respectively. As shown in Figure 2C, taking the equilateral triangle mask as an example, for a given circumcircle radius r ₀ , the coordinates of the three vertices are

Then, the phase of the inner area of the triangle is shielded by the mask mask2(i, j)=0, which is displayed as black;

如图2E所示；4) Phase writing: The black area in the figure is shielded, and the phase is no longer written; starting from a vertex of the mask pattern, the phase is written outside the mask pattern, starting from any vertex of the mask pattern as a reference point, along the Clockwise, the coordinates of the reference point are obtained according to the step distance dxy=l/ntuopuhe. As shown in Figure 2D, the position and number of the reference point on each boundary of the mask triangle are marked, where ntuopuhe ∈ (1, 20), representing each The number of reference points on the edge, l is the side length of the mask graphic, the coordinates of the current reference point are (x ₀ , y ₀ ), and the pixel coordinates of any point outside the masked area are (i, j)(i , j∈(1, 1080)), then the pixel distance between these two points is r:

As shown in Figure 2E;

a) When any point (i, j) is on the left side of the current reference point (x ₀ , y ₀ ), i.e. i≤x ₀ , as shown in Figure 2E, the azimuth of the point relative to the reference point is theta= arccos[(jy ₀ )/r), the phase value is phase(i, j)=(theta)*q;

b) When any point (i, j) is on the right side of the current reference point (x ₀ , y ₀ ), i.e. i>x ₀ , as shown in Figure 2F, the azimuth of the point relative to the reference point is theta= arccos[(jy ₀ )/r], the phase value is phase(i, j)=(theta)*q.

5) After completing the above operations, the number of topological charges is automatically increased by 1, so that the phase value of any point (i, j) is updated according to phase1(i,j)=phase1(i,j)+phase(i,j); Update the reference point with a fixed step distance dxy, and then repeat the process of 4) until the updated reference point returns to the starting reference point;

6) Convert the phase value phase1(i,j) of any point (i,j) into gray value ho log rams tan dard(i, j), ho log rams tan dard(i, j) and phase1(i, The numerical correspondence of j) is: ho log rams tandard(i, j)=mod(phase1(i, j)*255/(2*pi), 255), and then save the hologram, as shown in Figure 3A hologram.

According to the above method, a hologram whose mask shape is a regular triangle, a regular quadrilateral, a regular pentagon and a regular hexagon can be obtained. As shown in FIG. 3B , the number of sides of the mask graphic corresponds to the number of lobes for subsequent processing; the hologram The positive or negative topological charge number determines the chirality direction of the processed structure; the absolute value of the topological charge number determines the size of the processed structure.

In a specific embodiment, using the femtosecond holographic processing system as shown in FIG. 4 , according to the hologram in FIG. 3A , the process of processing the chiral three-lobed microstructure is:

1) Prepare the sample to be processed: use SU2080 liquid photoresist as the processing material, the initial form of which is liquid, use a pipette to drop 10uL of liquid photoresist on a universal glass slide, and then place it on a hot plate to heat, control The temperature is 100°C and the heating time is 45min to completely cure the photoresist;

2) Process the sample to be processed: the laser 1 generates a femtosecond laser, controls the polarization direction of the laser through the half-wave plate 2 and the polarization beam splitter prism 3, and obtains linearly polarized Gaussian light; then the beam is expanded through the lens groups 4 and 5, In order to match the panel size of the spatial light modulator 9; the shutter 6 is controlled by the computer 19 to realize the on-off of the optical path, and the energy of the beam is controlled by the attenuator 7, and the femtosecond laser beam with adjusted energy is reflected by the high-reflection lens 8. It is irradiated on the spatial light modulator 9; the spatial light modulator 9 is connected to the computer 19, and the hologram played by the computer 19 can be loaded on the spatial light modulator 9, and the beam is phase-modulated according to the phase information of the hologram, thereby converting the linearly polarized Gaussian The light modulation generates the required chiral discrete light field, and the light field is reduced by the lens groups 10 and 12 (the focal lengths of the lenses 10 and 12 are 600mm and 200mm respectively), and the aperture 11 makes only the first part of the chiral discrete light field. The first-order light enters the microscope system, while the other-order light is blocked. The first-order light enters the entrance pupil of the 60x oil mirror 14 through the reflecting mirror 13, and is vertically incident on the inside of the photoresist sample 16 through its focusing; the photoresist sample 16 is upright fixed on the piezoelectric table 15, the computer 19 can control the movement of the piezoelectric table 15, thereby adjusting the spatial position of the beam focus in the photoresist sample 16; the photoresist sample 16 emits fluorescence under the illumination of the halogen lamp 17, The CCD 18 receives, and then transmits it to the computer 19, and the received image is displayed through the CCD driver installed on the computer 19, which can realize the monitoring of the processing process. Among them, the size of the beam power is detected by a power meter at 5 cm behind the diaphragm 11, and the power can be adjusted to an appropriate value through the attenuator 7; the exposure time is 0.5s, and the shutter 6 is controlled by the computer 19, as shown in Figure 5A, The equilateral triangular mask (N=3), the hologram in the processing system of Fig. 3 shows the light field simulation diagram at different positions behind the lens 11 (f=600mm), while Fig. 5B shows the regular quadrilateral mask (N=4), the regular five The simulation diagram of the light field at the focal point of the lens 11 with the polygonal mask (N=5) and the regular hexagonal mask (N=6);

3) Finish processing: fix the pre-baked photoresist sample 16 on the piezoelectric table 15, find the focal plane under the 60 times oil lens 14, open the shutter 6, and the photoresist sample 16 is chirality by femtosecond laser. The area illuminated by the discrete light field undergoes two-photon polymerization, resulting in a discretely expanded chiral multi-lobed microstructure, and the unirradiated area remains as it is.

In a specific embodiment, the photoresist sample 16 that has been processed above is placed in n-propanol for development for 30 minutes, the unpolymerized area is completely dissolved, and the polymerized area is left; take out to obtain a discrete and expanded chiral microstructure. , and then place the photoresist sample 16 horizontally to make the residual n-propanol on the surface volatilize rapidly. Before the liquid volatilization is complete, the photoresist sample 16 is subjected to the liquid capillary force. Under the capillary force, when the photoresist sample is When the height of the photoresist sample 16 is low, the chiral microstructure is still discrete; when the height of the photoresist sample 16 is high, the chiral microstructure self-assembles into an overall structure; as shown in FIG. The electron microscope image of the processed structure of the triangular mask (N=3, q=±15, r0=350) includes both discrete and assembled forms; Electron microscope images of the assembled structure of pentagonal mask (N=5) and regular hexagonal mask (N=6).

The preparation method of the chiral multi-lobed microstructure provided by the invention can control the height of the chiral multi-lobed microstructure and adjust the shape of the chiral multi-lobed microstructure after the action of capillary force, and can present a discrete state and an assembled state.

According to another aspect of the present invention, a preparation device for a chiral multi-lobed microstructure is provided, as shown in FIG. 7 , the device includes:

The hologram calculation unit 71 is used to calculate the hologram of the chiral multi-lobed microstructure;

The first acquisition unit 72 is configured to process the photoresist material sample by using the femtosecond holographic processing system according to the hologram to obtain the chiral multi-lobe microstructure sample to be developed;

The second acquisition unit 73 is used to put the chiral multi-lobed microstructure sample to be developed into a developing solution for development, and obtain a discrete and outwardly expanded chiral multi-lobed microstructure;

The third acquisition unit 74 is used for, after the discrete and outwardly expanded chiral multi-lobe microstructures are taken out from the developer, the chiral multi-lobe microstructures in a discrete state or an assembled state are obtained after the capillary force of the developer solution remaining on the surface is acted upon and closed inward. microstructure.

The preparation device of the chiral multi-lobe microstructure provided by the invention combines the femtosecond laser holography high-efficiency processing technology and the capillary force-driven self-assembly technology, can flexibly and quickly realize the preparation of the three-dimensional chiral multi-lobe microstructure, and improves the processing speed. efficiency.

In this embodiment, the hologram calculation unit 71 includes the following subunits:

The first setting subunit is to set the pixel size of the square hologram of the chiral multi-lobe microstructure, divide the square hologram into grids, define the pixel coordinates of each point on the square hologram, and initialize the total phase value of each pixel point. ;

The second setting subunit is used to add an outer circular mask with a suitable radius according to the pixel size of the square hologram and the circular spot feature of the femtosecond laser beam, and shield the invalid area outside the circular mask to obtain a circular hologram;

The mask pattern acquisition sub-unit adds a central regular polygon mask pattern to the circular hologram according to the principle of discrete superposition;

The phase value calculation subunit is used to calculate the phase value of any point outside the central regular polygon mask figure;

The hologram acquisition subunit is used to convert phase values to grayscale values and generate holograms of chiral multi-lobed microstructures. Wherein, the phase value calculation subunit also includes: a reference point selection subunit, and any vertex of the central regular polygon mask figure is selected as a starting reference point;

The pixel distance calculation subunit is used to calculate the pixel distance between any point outside the central regular polygon mask graphic and the starting reference point;

The azimuth angle calculation subunit is used to calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the starting reference point;

The phase value calculation subunit is used to calculate the phase value of any point outside the central regular polygon mask figure relative to the starting reference point according to the azimuth angle, and accumulate the phase value to the total phase value;

The phase value acquisition sub-unit updates the starting reference point according to the preset step distance to obtain a new reference point, and recalculates the phase value of any point outside the central regular polygon mask graph relative to the new reference point according to the new reference point. It is accumulated to the total phase value; this step is repeated until the new reference point returns to the starting reference point, then the total phase value obtained is the phase value of any point outside the central regular polygon mask graphic. The azimuth calculation subunit also includes:

The left side azimuth angle calculation unit is used to calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point by adopting the first calculation formula if any point outside the central regular polygon mask graphic is located on the left side of the reference point;

The right side azimuth angle calculation unit is used to calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point by using the second calculation formula if any point outside the central regular polygon mask graphic is located on the right side of the reference point. The device for preparing a chiral multi-lobed microstructure provided by the invention controls the number of petals of the chiral multi-lobed microstructure by changing the shape of the central mask of the hologram; Processing of the right chiral structure; by controlling the number of superpositions of the hologram, that is, the number of topological charges, the lateral size of the chiral structure can be controlled; by controlling the exposure depth, the vertical size of the chiral structure can be controlled.

In this embodiment, the third obtaining unit 74 includes the following subunits:

The assembled state acquisition subunit is used to obtain the assembled state after the discretely expanded chiral multilobe microstructure is subjected to the capillary force of the developer when the height of the discretely expanded chiral multilobe microstructure is higher than the preset height. The chiral multi-lobed microstructure of ;

The discrete state acquisition subunit is used for when the height of the discretely expanded chiral multi-lobed microstructure is lower than the preset height, the discretely expanded chiral multi-lobed microstructure is still discrete after the capillary force of the developer. The chiral multilobed microstructure of the state.

The preparation device of the chiral multi-lobed microstructure provided by the present invention can control the shape of the chiral structure driven by capillary force into two states of discrete and assembled by controlling the longitudinal dimension, that is, the height of the chiral multi-lobed microstructure.

So far, the present embodiment has been described in detail with reference to the accompanying drawings. From the above description, those skilled in the art should have a clear understanding of the present invention.

It should be noted that, in the accompanying drawings or the text of the description, the implementations that are not shown or described are in the form known to those of ordinary skill in the technical field, and are not described in detail.

It should also be noted that demonstrations of parameters including specific values may be provided herein, but these parameters need not be exactly equal to the corresponding values, but may be approximated within acceptable error tolerances or design constraints. The direction terms mentioned in the embodiments are only for referring to the directions of the drawings, and are not used to limit the protection scope of the present invention. Furthermore, unless the steps are specifically described or must occur sequentially, the order of the above steps is not limited to those listed above, and may be varied or rearranged according to the desired design. And the above embodiments can be mixed and matched with each other or with other embodiments based on the consideration of design and reliability, that is, the technical features in different embodiments can be freely combined to form more embodiments.

It should be noted that throughout the drawings, the same elements are denoted by the same or similar reference numerals. In the above description, some specific embodiments are only for the purpose of description, and should not be construed as any limitation to the present invention, but are only examples of embodiments of the present invention. Conventional structures or constructions will be omitted when it may lead to obscuring the understanding of the present invention. It should be noted that the shapes and sizes of the components in the figures do not reflect the actual size and proportion, but merely illustrate the contents of the embodiments of the present invention.

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

Claims (8)

1. a preparation method of chiral multi-valve microstructure, is characterized in that, described method comprises: Calculate holograms of chiral multi-lobed microstructures; According to the hologram, use a femtosecond holographic processing system to process the photoresist material sample to obtain a chiral multi-lobed microstructure sample to be developed; Putting the chiral multi-lobed microstructure sample to be developed into a developing solution for development to obtain a discrete and outwardly expanded chiral multi-lobed microstructure; After the discrete and outwardly expanding chiral multi-lobed microstructures are taken out from the developing solution, the chiral multi-lobed microstructures in a discrete state or an assembled state are obtained after the capillary force of the developing solution remaining on the surface is acted upon and closed inward; Among them, the hologram of the chiral multi-lobe microstructure is calculated by the following steps, including: Set the pixel size of the square hologram of the chiral multi-lobe microstructure, perform grid division on the square hologram, define the pixel coordinates of each point on the square hologram, and initialize the total phase value of each pixel point ; According to the pixel size of the square hologram and the circular spot characteristics of the femtosecond laser beam, an outer circular mask with a preset radius is added to shield the invalid area outside the circular mask to obtain a circular hologram; adding a central regular polygon mask figure on the circular hologram according to the discrete superposition principle; Calculate the phase value of any point outside the central regular polygon mask figure; The phase values are converted to grayscale values and a hologram of the chiral multilobed microstructure is generated. 2. The method according to claim 1, wherein calculating the phase value of any point outside the central regular polygon mask figure, comprising: Select any vertex of the central regular polygon mask graphic as a starting reference point; Calculate the pixel distance between any point outside the central regular polygon mask graphic and the starting reference point; Using the pixel distance, calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the starting reference point; According to the azimuth angle, calculate the phase value of any point outside the central regular polygon mask pattern relative to the starting reference point, and accumulate the phase value to a total phase value; Update the starting reference point at a preset step to obtain a new reference point, and recalculate the phase value of any point outside the central regular polygon mask graphic relative to the new reference point according to the new reference point , accumulate it to the total phase value; repeat this step until the new reference point returns to the starting reference point, then the total phase value obtained is the outside of the central regular polygon mask figure Phase value at any point. 3. The method according to claim 2, wherein, according to the azimuth angle, calculating the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point, comprising: If any point outside the central regular polygon mask graphic is located on the left side of the reference point, use the first calculation formula to calculate the azimuth angle of any point outside the central regular polygon mask graphic relative to the reference point; If any point outside the central regular polygon mask figure is located on the right side of the reference point, the second calculation formula is used to calculate the azimuth angle of any point outside the central regular polygon mask figure relative to the reference point. 4. method according to claim 1, is characterized in that, after the capillary force of described developing solution, the chiral multi-lobe microstructure of the discrete outward expansion is obtained, and the chiral multi-lobe microstructure of discrete state or assembled state is obtained. structure, including: When the height of the discretely expanded chiral multi-lobed microstructure is higher than a preset height, the discretely expanded chiral multi-lobed microstructure is subjected to the capillary force of the developer to obtain an assembled hand. Sexual multi-lobed microstructure; When the height of the discretely expanded chiral multi-lobed microstructure is lower than a preset height, the discretely expanded chiral multi-lobed microstructure is still in a discrete state after being acted by the capillary force of the developer. Chiral multi-lobed microstructures. 5. a preparation device of chiral multi-lobed microstructure, is characterized in that, described device comprises: The hologram calculation unit is used to calculate the hologram of the chiral multi-lobed microstructure; a first acquisition unit, configured to process a photoresist material sample using a femtosecond holographic processing system according to the hologram to obtain a chiral multi-lobe microstructure sample to be developed; The second acquisition unit is used to put the chiral multi-lobed microstructure sample to be developed into a developing solution for development, and obtain a discrete and outwardly expanded chiral multi-lobed microstructure; The third acquisition unit, after the discrete and outwardly expanding chiral multi-lobed microstructures are taken out from the developing solution, they are closed inward by the capillary force of the developing solution remaining on the surface to obtain discrete or assembled chirality Multi-lobed microstructure; Wherein, the hologram calculation unit includes: The first setting subunit is used to set the pixel size of the square hologram of the chiral multi-lobe microstructure, perform grid division on the square hologram, define the pixel coordinates of each point on the square hologram, and initialize each point. The total phase value of the pixel point; The second setting subunit is used for adding an outer circular mask with a preset radius according to the pixel size of the square hologram and the circular spot characteristics of the femtosecond laser beam, and shielding the invalid area outside the circular mask to obtain circular hologram; a mask pattern acquiring subunit, used for adding a central regular polygon mask pattern on the circular hologram according to the discrete superposition principle; a phase value calculation subunit, used to calculate the phase value of any point outside the central regular polygon mask figure; The hologram acquisition sub-unit is used for converting the phase value into a gray value and generating a hologram of the chiral multi-lobed microstructure. 6. The apparatus according to claim 5, wherein the phase value calculation subunit comprises: The reference point selection subunit is used to select any vertex of the central regular polygon mask figure as a starting reference point; a pixel distance calculation subunit, used to calculate the pixel distance between any point outside the central regular polygon mask figure and the starting reference point; an azimuth angle calculation subunit, used to calculate the azimuth angle of any point outside the central regular polygon mask figure relative to the starting reference point; a phase value calculation subunit, configured to calculate the phase value of any point outside the central regular polygon mask figure relative to the starting reference point according to the azimuth angle, and accumulate the phase value to the total phase value; The phase value acquisition sub-unit updates the starting reference point at a preset step to obtain a new reference point, and recalculates the relative relationship between any point outside the central regular polygon mask graph according to the new reference point relative to the new reference point. The phase value of the reference point is accumulated to the total phase value; this step is repeated until the new reference point returns to the starting reference point, then the total phase value obtained is the central regular polygon Phase value at any point outside the mask pattern. 7. The apparatus according to claim 6, wherein the azimuth angle calculation subunit comprises: The left side azimuth angle calculation unit is used to calculate, if any point outside the central regular polygon mask figure is located on the left side of the reference point, using the first calculation formula to calculate the relative relationship between any point outside the central regular polygon mask figure relative to the reference point. the azimuth of the reference point; The right side azimuth angle calculation unit is used to calculate the relative position of any point outside the central regular polygon mask graphic relative to the The azimuth of the reference point. 8. The apparatus according to claim 5, wherein the third acquiring unit comprises: The assembled state acquisition subunit is used for, when the height of the discretely expanded chiral multi-lobed microstructure is higher than a preset height, the discrete and expanded chiral multi-lobed microstructure passes through the capillary force of the developer After the action, an assembled chiral multi-lobed microstructure is obtained; The discrete state acquisition subunit is used for, when the height of the discretely expanded chiral multi-lobed microstructure is lower than a preset height, the discrete expanded chiral multi-lobed microstructure passes through the capillary force of the developer After the action, it is still a discrete chiral multi-lobed microstructure.

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