Liquid Surface Micro-Nano Particle Directional Manipulation Device and Manipulation Method

Abstract

The present invention provides a device and a method for directionally manipulating micro-nano particles on the liquid surface. The device for directionally manipulating micro-nano particles on the liquid surface includes a spherical curved transparent container and a pump laser. The spherical curved transparent container is used to hold the liquid. The pump laser is located below the spherical curved transparent container and is used to emit pump light. The pump light is incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air to induce protrusions. The protrusions trigger capillary forces at the interface between the liquid and the air. The micro-nano particles are attracted by the capillary forces and move towards the protrusions. When the micro-nano particles have not reached the central position of the protrusions, the capillary forces become repulsive forces, causing the micro-nano particles to stop moving. The present invention can achieve the manipulation and capture of micro-nano particles without invading the micro-nano particles, and has the advantages of simple structure, convenient use and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of micro-nano particle manipulation, and particularly to a non-invasive device and method for directionally manipulating micro-nano particles on the liquid surface. Background Art

[0002] Currently, the capture and manipulation of dielectric or biological particles on the liquid interface or the surface of transparent biofilms have extremely important and broad application prospects in the fields of life science, medicine, genetic engineering, chemistry, physics, materials science, etc. How to manipulate particles under various conditions without damage has a very important need.

[0003] Currently, the manipulation and capture of micro-nano particles are mainly achieved by means such as optical tweezers, acoustic tweezers, electromagnetic tweezers, and micro-nano structures. Although the manipulation and capture technology of micro-nano particles are widely used in basic research, most methods require complex experimental devices and have many limitations for specific applications. For example, the direct interaction between the laser spot and the captured micro-nano particles will significantly cause unnecessary thermal effects; the processing and manufacturing of micro-columns are relatively complex and have low efficiency. Including but not limited to the above factors, the traditional manipulation and capture technology of micro-nano particles is complex, with high usage costs and inconvenient use. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art, and propose a device and method for directionally manipulating micro-nano particles on the liquid surface. By using the optical pressure to cause the liquid surface to bend and generate capillary force, the micro-nano particles are directionally manipulated and captured by the capillary force. Since there is no need to invade the micro-nano particles, non-destructive manipulation and capture of the micro-nano particles can be achieved.

[0005] To achieve the above purpose, the present invention adopts the following specific technical solutions:

[0006] The device for directionally manipulating micro-nano particles on the liquid surface provided by the present invention includes a pump laser and a spherical curved transparent container; wherein, the spherical curved transparent container is used to hold the liquid; the pump laser is located below the spherical curved transparent container, and the pump laser is used to emit pump light. The pump light is incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air to induce a protrusion. The protrusion causes the interface between the liquid and the air to generate capillary force. The micro-nano particles are attracted by the capillary force and move towards the protrusion, and when they do not reach the center position of the protrusion, the capillary force becomes a repulsive force, causing the micro-nano particles to stop moving.

[0007] Preferably, the liquid surface micro-nano particle directional manipulation device further includes N reflectors, where N≥2. Among them, the first reflector is located in the emission direction of the pump laser, and the remaining reflectors are respectively located in the total reflection direction of the liquid-air interface. The pump light is reflected by the first reflector and enters the liquid-air interface from the bottom of the spherical curved transparent container at the total reflection angle, and is successively totally reflected to the remaining reflectors, inducing one or more protrusions at the liquid-air interface.

[0008] Preferably, an annular angular momentum phase plate or a spatial light modulator is provided between the pump laser and the first reflector to change the spot shape of the pump light.

[0009] Preferably, the liquid surface micro-nano particle directional manipulation device further includes a detection laser, a first beam splitter, a third reflector, a photodetector and an oscilloscope. The first beam splitter is located in the emission direction of the detection laser, the third reflector is located in the transmission direction of the first beam splitter, and the photodetector is located in the reflection direction of the first beam splitter. The detection laser is used to detect the interference light. The detection light emitted by the laser is transmitted through the first beam splitter to the third reflector, and is reflected by the third reflector and perpendicularly incident on the liquid. The detection light forms interference light after being reflected by the liquid-air interface and the interface between the liquid and the spherical curved transparent container. The interference light is reflected by the third reflector to the first beam splitter, and is reflected by the first beam splitter to the photodetector. The photodetector converts the received interference light into an interference electrical signal and inputs it to the oscilloscope.

[0010] Preferably, the liquid surface micro-nano particle directional manipulation device further includes a display and a second beam splitter. The second beam splitter is located in the opposite reflection direction of the first beam splitter, the display is located in the reflection direction of the second beam splitter, and the oscilloscope is located in the transmission direction of the second beam splitter. The interference light is reflected by the first beam splitter to the second beam splitter. A part of the interference light is reflected to the display for interference fringe display, and the other part of the interference light is transmitted to the photodetector and converted into an interference electrical signal and input to the oscilloscope.

[0011] Preferably, the pump light is green light and the detection light is red light.

[0012] The liquid surface micro-nano particle directional manipulation method provided by the present invention includes the following steps:

[0013] S1. The pump laser emits pump light, and the pump light enters the liquid-air interface from the bottom of the spherical curved transparent container to induce protrusions, and the protrusions cause capillary force to be generated at the liquid-air interface;

[0014] S2. The micro-nano particles are attracted by the capillary force and move towards the protrusions, and when they do not reach the central position of the protrusions, the capillary force becomes a repulsive force, causing the micro-nano particles to stop moving.

[0015] Preferably, after step S2, the following steps are further included:

[0016] S3. The detection laser emits detection light, and the detection light is transmitted through the first beam splitter to the third mirror, and is perpendicularly incident on the protrusion after being reflected by the third mirror;

[0017] S4. The detection light forms interference light after being reflected by the protrusion and reflected by the interface between the liquid and the spherical curved transparent container;

[0018] S5. The interference light is reflected by the third mirror to the first beam splitter, and then reflected by the first beam splitter to the photodetector. The photodetector converts the received interference light into an interference electrical signal and inputs it to the oscilloscope.

[0019] S6. By analyzing the signal of the oscilloscope, the deformation amount of the protrusion is measured according to the following formula :

[0020]

[0021] wherein, represents the refractive index of the liquid, represents the wavelength of the detection light.

[0022] Preferably, by moving the third mirror, the incident position of the detection light at the interface between the liquid and the air is changed, and interference fringes at different positions on the interface between the liquid and the air are obtained.

[0023] Preferably, the spot shape of the pump light is adjusted by a ring angular momentum phase plate or a spatial light modulator, and the energy of the pump light is adjusted by a pump light laser to change the shape of the protrusion.

[0024] The present invention can achieve the following technical effects:

[0025] 1. The liquid surface is bent by the protrusion to generate a capillary force. This capillary force initially manifests as an attractive force, pushing the micro-nano particles towards the protrusion. However, when approaching the protrusion position, due to the change of the curvature gradient of the liquid surface to the critical position, the capillary force changes from an attractive force to a repulsive force, causing the micro-nano particles to stop moving, realizing the manipulation and capture of the micro-nano particles. Since the micro-nano particles are not directly irradiated by the pump light, damage to the micro-nano particles can be avoided.

[0026] 2. By adjusting the power, spot size, and polarization of the pump light, the deformation of the liquid surface is changed, and the curvature gradient of the liquid surface is adjusted to achieve the directional manipulation and capture of micro-nano particles at different positions and directions;

[0027] 3. By using the detection light and interference measurement technology, the deformation amount of any position on the protrusion and the liquid surface can be realized.

[0028] 4. Compared with the existing micro-nano particle manipulation and capture devices, it is simple in structure, convenient to use, and inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a liquid surface micro-nano particle directional manipulation device according to an embodiment of the present invention;

[0030] Figure 2a is a comparison diagram of protrusions for different liquids according to an embodiment of the present invention;

[0031] Figure 2b is Figure 2a a change diagram of the curvature gradient generated by each protrusion in

[0032] Figure 3a is a comparison diagram of protrusions induced by pump light with different diameters according to an embodiment of the present invention;

[0033] Figure 3b is Figure 3a a change diagram of the curvature gradient generated by each protrusion in

[0034] Figure 4 is a comparison diagram of protrusions induced by double pump light and a change diagram of the curvature gradient generated by each protrusion according to an embodiment of the present invention;

[0035] Figure 5 is a movement trajectory diagram of micro-nano particles according to an embodiment of the present invention;

[0036] Figure 6 is a schematic flow diagram of a liquid surface micro-nano particle directional manipulation method according to an embodiment of the present invention.

[0037] The reference numerals therein include: spherical curved surface transparent container 1, pump laser 2, liquid 3, protrusion 4, micro-nano particle 5, first mirror 6, second mirror 7, detection laser 8, first beam splitter 9, second beam splitter 10, display 11, third mirror 12, photodetector 13, oscilloscope 14, laser shutter 15, annular angular momentum phase plate 16, CMOS camera 17, controller 18. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0040] The specific solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Figure 1 The structure of a liquid surface micro-nano particle directional manipulation device according to an embodiment of the present invention is shown.

[0042] As Figure 1 shown, the liquid surface micro-nano particle directional manipulation device of the embodiment of the present invention includes a spherical curved transparent container 1 and a pump laser 2. The spherical curved transparent container 1 is used to hold a liquid. The pump laser 2 is located below the spherical curved transparent container 1. The pump laser 2 is used to emit pump light, and the pump light is incident on the surface of the liquid from the bottom of the spherical curved transparent container 1.

[0043] The pump light emitted by the pump laser 2 is a Gaussian beam. The focus of the Gaussian beam is the beam waist. The emission of the pump laser 2 is controlled by a laser shutter 15.

[0044] The spherical curved transparent container 1 is a container made of a transparent material, such as a transparent material like glass or an acrylic plate, which facilitates the pump light to pass through the container and irradiate the liquid. The spherical curved surface of the spherical curved transparent container 1 means that the bottom surface of the transparent container is a regular curved surface, rather than an irregular curved surface similar to a wavy line, to avoid scattering when the pump light is incident on the bottom of the spherical curved transparent container 1.

[0045] The spherical curved transparent container 1 is selected with a relatively large radius of curvature to ensure that the container wall of the spherical curved transparent container 1 does not affect the meniscus effect generated by the light emission of the pump laser 2 (the surface tension of the liquid is affected by the surface energy of the container, and the liquid in the container is not vertical but in a meniscus shape). Due to the limited size of the spherical curved transparent container 1, the liquid 3 is actually a liquid droplet, and the central height of the liquid droplet is less than 2 mm, and the diameter is about 20 mm.

[0046] The surface of the liquid 3 is the interface between the liquid 3 and air. When the pump light is incident from the bottom of the spherical curved transparent container 1 onto the surface of the liquid 3, the light pressure of the pump light is utilized to generate optical momentum at the interface between the liquid 3 and air, thereby inducing a protrusion 4 at the interface between the liquid 3 and air. The protrusion 4 and the light pressure will cause the interface between the liquid and air to bend, and finally capillary force is generated at the interface between the liquid 3 and air. The capillary force first acts as an attractive force on the micro-nano particles 5 (micrometer particles or nanometer particles) on the liquid surface, attracting the micro-nano particles to move towards the protrusion 4. However, when the micro-nano particles 5 approach the position of the protrusion 4, due to the change of the curvature gradient of the liquid surface to the critical position, the capillary force changes from an attractive force to a repulsive force, causing the micro-nano particles 5 to be repelled and stop moving. At this time, the micro-nano particles 5 do not reach the center position of the protrusion 4, and the pump light cannot directly irradiate the micro-nano particles 5, thus avoiding damage to the micro-nano particles 5.

[0047] Figure 5 Shows the movement trajectory of the micro-nano particles according to an embodiment of the present invention.

[0048] As Figure 5 shown, the complete trajectory of the micro-nano particles 5 being attracted to the protrusion 4 can be seen. It can be observed that the relative position relationship of the micro-nano particles in time and space conforms to the quarter-power law, indicating that the movement trajectory of the micro-nano particles is non-linear but shows a quarter-power relationship, which is convenient for predicting the movement trajectory of the micro-nano particles.

[0049] The present invention manipulates and captures the micro-nano particles 5 dominated by capillary force, and the capillary force is provided by the surface gradient generated by the protrusion 4 on the liquid surface. That is to say, the protrusion 4 will cause the liquid surface to bend, generating a surface gradient, and finally generating capillary force on the liquid surface. By adjusting the surface gradient of the liquid surface, the capillary energy can be changed to achieve the manipulation of the micro-nano particles 5.

[0050] The method of adjusting the surface gradient of the liquid surface is as follows: The surface gradient is adjusted by changing the spot diameter of the pump light, the optical power of the pump light, and the polarization of the pump light, etc. A steeper curvature gradient will generate greater capillary energy. A 1-μm protrusion can manipulate 2-μm micro-nano particles, and the capillary energy generated by a 1-μm protrusion is equivalent to the capillary energy generated by a 250-μm micro-column on 2-μm micro-nano particles.

[0051] The surface tensions of different liquids 3 are different, and the heights of the induced protrusions are also different. By changing the liquid 3, protrusions of different heights can be generated.

[0052] In the embodiments of the present invention, studies were conducted on the protrusions induced by changing different liquids 10 under the same pump light power and beam waist radius. The research results are as Figure 2a and Figure 2bAs shown, the height of the protrusion caused by a liquid with a surface tension of 0.035 N / m under a pump light power of 4.2 W and an equivalent beam waist radius of 7 μm is different from that of a liquid with a surface tension of 0.075 N / m under a pump light power of 4.2 W and a beam waist radius of 7 μm. From Figure 2a and Figure 2b it can be seen that the greater the surface tension of the liquid, the lower the height of the protrusion. At the center position of the pump light spot, regardless of the change in the surface tension of the liquid, the height of the protrusion is always the largest. In addition, from the change in the curvature gradient of the liquid surface, it can be seen that the lower the surface tension of the liquid, the greater the curvature gradient corresponding to the pump light irradiation area.

[0053] In the embodiment of the present invention, the protrusions induced under the conditions of different beam waist radii of the pump light, the same liquid, and pump light power are also studied. The research results are as Figure 3a and Figure 3b shown. When the liquid is water and the pump light power is 4.2 W, the protrusions induced by pump lights with beam waist radii of 10 μm, 15 μm, and 20 μm are respectively measured by interference. The measurement results show that when the beam waist radius is 10 μm, the limit height of the protrusion is close to 1 μm; when the beam waist radius is 15 μm, the limit height of the protrusion is 800 nm; when the beam waist radius is 20 μm, the limit height of the protrusion is about 750 μm. And it can be seen that when the beam waist radius is 10 μm, the curvature gradient generated by the protrusion is the largest, and as the beam waist radius increases, the curvature gradient generated by the protrusion gradually becomes smaller, and the capture area of the micro-nano particles is given.

[0054] The structure of the micro-nano particle directional manipulation device on the liquid surface provided above can only induce one protrusion on the liquid surface to form a single-peak particle capture region. To facilitate the capture of micro-nano particles, two or more protrusions can also be induced on the liquid surface by adding structures to form particle capture regions of different shapes such as double-peak particle capture regions and triple-peak particle capture regions, thereby realizing precise and effective particle manipulation.

[0055] To form more protrusions, the micro-nano particle directional manipulation device on the liquid surface further includes N reflectors, N≥2. The first reflector is arranged in the outgoing direction of the pump laser 2, and the remaining reflectors are respectively arranged in the total reflection direction of the interface between the liquid 3 and the air. Here, the double-peak particle capture region is taken as an example for illustration, and the same applies to other shaped particle capture regions.

[0056] To induce two protrusions, the liquid surface micro-nano particle directional manipulation device further includes a first mirror 6 and a second mirror 7. The first mirror 6 is located in the emission direction of the pump laser 2, and the second mirror 7 is located in the total reflection direction of the interface between the liquid and the air. The pump light is reflected by the first mirror 6 and then enters the interface between the liquid 3 and the air from the bottom of the spherical curved transparent container 1 at the total reflection angle to induce the generation of the first protrusion, and is totally reflected to the second mirror 7. After being reflected by the second mirror 7, it enters the interface between the liquid 3 and the air again to induce the generation of the second protrusion. The area between the two protrusions forms a double-peak particle capture area for capturing the micro-nano particles 5.

[0057] Figure 4 Shows the comparison of the protrusions induced by the double pump light according to the embodiments of the present invention and the change of the curvature gradient generated by each protrusion.

[0058] As Figure 4 shown, when the liquid is water, the pump light power is 4.2 W, and the beam waist radius is 20 μm, it can be seen that two protrusions are formed at the interface between the liquid and the air. The area between the two protrusions is the double-peak particle capture area, and the micro-nano particles are more likely to be captured in the double-peak particle capture area.

[0059] Due to the existence of reflection, the protrusion induced after the reflection of the pump light is slightly lower than the directly induced protrusion, making the particle capture area form a directional curvature gradient, and this directional curvature gradient can better manipulate the micro-nano particles dominated by the capillary force.

[0060] And by adjusting the angle of the second mirror 7, the distance between the two pump lights can be changed, the range of the particle capture area can be reduced or enlarged, or the shape of the protrusion can be adjusted by the spatio-temporal distribution of multiple pump lights or beam energies, so as to realize the capture and manipulation of micro-nano particles in different regions.

[0061] It is also possible to adjust the angle of the second mirror 7 so that the pump lights reflected by the first mirror 6 and the second mirror 7 act on the same position on the liquid surface. At this time, only one protrusion is formed, and the pump light reflected by the second mirror 7 is used to strengthen this protrusion.

[0062] The present invention can also set multiple mirrors so that the multiple formed protrusions surround together to form an annular particle capture area.

[0063] The N mirrors are all installed on the adjustment mechanism, and the angles and directions of each mirror are adjusted by controlling the adjustment mechanism.

[0064] By changing the beam energy of the pump light, the shape and size of the protrusion 4 can be changed. To change the shape of the protrusion 4, it is necessary to change the spot shape of the pump light. In the example of the present invention, an annular angular momentum phase plate 16 is provided between the pump laser 2 and the first mirror 6. By means of the annular angular momentum phase plate 16, the spot shape of the pump light is changed, thereby changing the shape of the formed protrusion 4. Of course, the annular angular momentum phase plate 16 can be replaced by a modulation device such as a spatial light modulator that can change the spot shape.

[0065] In order to detect any position on the protrusion or the liquid surface, the liquid surface micro-nano particle directional manipulation device provided by the embodiment of the present invention further includes a detection laser 8, a first beam splitter 9, a second beam splitter 10, a display 11, a third mirror 12, a photodetector 13, and an oscilloscope 14. The first beam splitter 9 is located in the emission direction of the detection laser 8. The second beam splitter 10 is located in the reflection direction of the first beam splitter 9. The display 11 is located in the reflection direction of the second beam splitter 10. The third mirror 12 is located in the transmission direction of the first beam splitter 9. The photodetector 13 is located in the reflection direction of the first beam splitter 9. The oscilloscope 14 is located in the transmission direction of the second beam splitter 10. The position signal of the laser shutter 15 is collected by the oscilloscope 2.

[0066] The detection light emitted by the detection laser 8 is transmitted through the first beam splitter 9 to the third mirror 12, and is reflected by the third mirror 12 and vertically incident on the protrusion 4. The detection light forms interference light after being reflected by the interface between the liquid 3 and the air and the interface between the liquid 3 and the spherical curved transparent container 1. The interference light is reflected by the third mirror 12 to the first beam splitter 9, and then reflected by the first beam splitter 9 to the second beam splitter 10. A part of the interference light is reflected to the display 11, and a Newton's ring-shaped fringe pattern is formed on the display screen 11. Another part of the interference light is transmitted to the photodetector 13 and is converted into an interference electrical signal and input to the oscilloscope 14.

[0067] By analyzing the signal of the oscilloscope 14, the deformation amount of the protrusion can be measured :

[0068]

[0069] wherein, represents the refractive index of the liquid, represents the wavelength of the detection light.

[0070] By moving the third mirror 12, the position where the detection light is incident on the interface between the liquid 3 and the air can be adjusted, and interference fringes at different positions on the interface between the liquid 3 and the air can be obtained, that is, the deformation amount at any position on the interface between the liquid 3 and the air can be obtained.

[0071] The liquid 3 is selected as a liquid with high transmittance to the detection light, such as water. Chemical components can be added to the liquid to change the surface tension of the liquid and generate protrusions of different heights. For example, sodium dodecyl sulfate is added to water.

[0072] When the liquid 3 is a water droplet, the pump laser 2 is preferably a green laser. Since water has a high transmittance to the green light emitted by the pump laser 2, the thermal effect during laser irradiation can be greatly reduced, and the influence of the protrusion 4 caused by the thermal effect can be reduced.

[0073] Since the liquid 3 will naturally evaporate in the spherical curved transparent container 1, the height of the liquid 3 gradually decreases, affecting the stability of the interference fringes. To improve the stability of the interference fringes, a transparent container cover is covered on the opening of the spherical curved transparent container 1 to reduce the natural evaporation of the liquid 3 and ensure the stability of the interference fringes.

[0074] Since the radius of curvature of the spherical curved transparent container 1 will directly affect the interference measurement result, the ideal value of the radius of curvature is 100 cm. If a spherical curved transparent container 1 with too large a radius of curvature is used, the interference measurement result will be too small. If a spherical curved transparent container 1 with too small a radius of curvature is used, the measurement result will be too large. Therefore, a spherical curved transparent container 1 with a radius of curvature of about 100 cm is selected.

[0075] To enable closed-loop control of the manipulation of micro-nano particles, the liquid surface micro-nano particle directional manipulation device provided by the embodiment of the present invention further includes a connected CMOS camera 17 and a controller 18. The CMOS camera 17 is arranged above the spherical curved transparent container 1 and is used to collect the movement trajectory of the micro-nano particle 5 and transmit it to the controller 18. The controller 18 is also connected to the adjustment mechanisms of the laser shutter 15, the annular angular momentum phase plate 16, and the first reflector 6, and is used to generate a control signal according to the preset movement trajectory and the actual movement trajectory of the micro-nano particle 5, and transmit the control signal to the adjustment mechanisms of the laser shutter 15, the annular angular momentum phase plate 16, and the first reflector 6 respectively, so as to adjust the energy spatio-temporal distribution of the pump light and precisely manipulate the micro-nano particle 5 to move according to the preset movement trajectory.

[0076] The above content details the liquid surface micro-nano particle directional manipulation device and its working principle provided by the embodiment of the present invention. The embodiment of the present invention also provides a method for directionally manipulating micro-nano particles by using the liquid surface micro-nano particle directional manipulation device.

[0077] Figure 6 The flow of the liquid surface micro-nano particle directional manipulation method according to the embodiment of the present invention is shown.

[0078] As Figure 6As shown in the figure, the method for directionally manipulating micro-nano particles on the liquid surface according to the embodiment of the present invention includes the following steps:

[0079] S1. The pump laser emits pump light, and the pump light is incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air to induce protrusions, and the protrusions trigger capillary force at the interface between the liquid and the air.

[0080] The light pressure of the pump light is used to generate optical momentum at the interface between the liquid and the air, thereby inducing protrusions at the interface between the liquid and the air. The protrusions and the light pressure will cause the interface between the liquid and the air to bend, and finally capillary force is generated at the interface between the liquid and the air.

[0081] S2. The micro-nano particles are attracted by the capillary force and move towards the protrusions. When the micro-nano particles do not reach the central position of the protrusions, the capillary force becomes a repulsive force, causing the micro-nano particles to stop moving.

[0082] The capillary force first shows an attractive force to the micro-nano particles (micrometer particles or nanometer particles) on the liquid surface, attracting the micro-nano particles to move towards the protrusions. However, when the micro-nano particles approach the protrusion position, due to the change of the curvature gradient of the liquid surface to the critical position, the capillary force changes from an attractive force to a repulsive force, causing the micro-nano particles to be repelled and stop moving. At this time, the micro-nano particles do not reach the protrusion position, and the pump light cannot directly irradiate the micro-nano particles, avoiding damage to the micro-nano particles.

[0083] In the embodiment of the present invention, multiple protrusions can also be induced on the interface between the liquid and the air by adding a reflecting mirror to form particle capture regions of different shapes, such as: double-peak particle capture regions, triple-peak particle capture regions, annular particle capture regions, etc. For specific details, please refer to the above description about the N reflecting mirror, which will not be elaborated here.

[0084] Preferably, after step S2, the following steps are further included:

[0085] S3. The detection laser emits detection light, and the detection light is transmitted through the first beam splitter to the third reflecting mirror and is reflected vertically by the third reflecting mirror to the protrusion.

[0086] S4. The detection light forms interference light after being reflected by the protrusion and the interface between the liquid and the spherical curved transparent container.

[0087] S5. The interference light is reflected by the third reflecting mirror to the first beam splitter, and then reflected by the first beam splitter to the photodetector. The photodetector converts the received interference light into an interference electrical signal and inputs it to the oscilloscope.

[0088] S6. By analyzing the signals of the oscilloscope, the height and deformation amount of the protrusion can be measured. :

[0089]

[0090] wherein, represents the refractive index of the liquid, represents the wavelength of the probe light.

[0091] In a specific example of the present invention, by moving the third mirror, the incident position of the probe light at the interface between the liquid and air is changed, and interference fringes at different positions on the interface between the liquid and air are obtained.

[0092] In another specific example of the present invention, the spot shape of the pump light is adjusted by an annular angular momentum phase plate or a spatial light modulator, and the energy of the pump light is adjusted by a pump light laser to change the shape of the protrusion.

[0093] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0094] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0095] The above specific implementation manners of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for directionally manipulating micro-nano particles on the liquid surface, characterized in that, It includes a pump laser and a spherical curved transparent container; wherein, the spherical curved transparent container is used to hold a liquid; the pump laser is located below the spherical curved transparent container. The pump laser is used to emit pump light, and the pump light is incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air to induce protrusions. The protrusions trigger the generation of capillary force at the interface between the liquid and the air. Micro-nano particles are attracted by the capillary force and move towards the protrusions. When the micro-nano particles have not reached the central position of the protrusions, the capillary force becomes a repulsive force, causing the micro-nano particles to stop moving.

2. The liquid surface micro-nano particle directional manipulation device according to claim 1, characterized in that It further includes N mirrors, where N≥2. Among them, the first mirror is located in the emission direction of the pump laser, and the remaining mirrors are respectively located in the total reflection directions of the interface between the liquid and the air. The pump light is reflected by the first mirror and then incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air at the total reflection angle, and is successively totally reflected to the remaining mirrors, inducing one or more protrusions at the interface between the liquid and the air.

3. The liquid surface micro-nano particle directional manipulation device according to claim 2, characterized in that, An annular angular momentum phase plate or a spatial light modulator is arranged between the pump laser and the first mirror to change the spot shape of the pump light.

4. The liquid surface micro-nano particle directional manipulation device according to any one of claims 1 to 3, characterized in that, It further includes a detection laser, a first beam splitter, a third mirror, a photodetector and an oscilloscope. The first beam splitter is located in the emission direction of the detection laser. The third mirror is located in the transmission direction of the first beam splitter. The photodetector is located in the reflection direction of the first beam splitter. The detection laser is used to detect interference light. The detection light emitted by the laser is transmitted through the first beam splitter to the third mirror, and is reflected by the third mirror and perpendicularly incident on the liquid. The detection light forms interference light after being reflected by the interface between the liquid and the air and the interface between the liquid and the spherical curved transparent container. The interference light is reflected by the third mirror to the first beam splitter, and is reflected by the first beam splitter to the photodetector. The photodetector converts the received interference light into an interference electrical signal and inputs it to the oscilloscope.

5. The liquid surface micro-nano particle directional manipulation device according to claim 4, characterized in that, It further includes a display and a second beam splitter. The second beam splitter is located in the opposite reflection direction of the first beam splitter. The display is located in the reflection direction of the second beam splitter. The oscilloscope is located in the transmission direction of the second beam splitter. The interference light is reflected by the first beam splitter to the second beam splitter. A part of the interference light is reflected to the display for displaying interference fringes, and the other part of the interference light is transmitted to the photodetector and is converted into an interference electrical signal and input to the oscilloscope.

6. The liquid surface micro-nano particle directional manipulation device according to claim 4, wherein The pump light is green light, and the detection light is red light.

7. A method for directional manipulation of micro-nano particles on a liquid surface, which uses the liquid surface micro-nano particle directional manipulation device described in claim 4, characterized in that, The method includes the following steps: S1. The pump laser emits pump light, and the pump light is incident from the bottom of the spherical curved transparent container to the interface between the liquid and the air to induce protrusions, and the protrusions trigger the generation of capillary force at the interface between the liquid and the air; S2. The micro-nano particles are attracted by the capillary force and move towards the protrusion. When they do not reach the central position of the protrusion, the capillary force becomes a repulsive force, causing the micro-nano particles to stop moving.

8. The method for directionally manipulating liquid surface micro-nano particles according to claim 7, which uses the device for directionally manipulating liquid surface micro-nano particles according to claim 4, is characterized in that, After step S2, the following steps are further included: S3. The detection laser emits detection light. The detection light is transmitted through the first beam splitter to the third reflector and is vertically incident on the protrusion after being reflected by the third reflector. S4. The detection light forms interference light after being reflected by the protrusion and by the interface between the liquid and the spherical curved transparent container. S5. The interference light is reflected by the third reflector to the first beam splitter, and then reflected by the first beam splitter to the photodetector. The photodetector converts the received interference light into an interference electrical signal and inputs it to the oscilloscope. S6. By analyzing the signals of the oscilloscope, the deformation amount of the protrusion is measured according to the following formula : Wherein, represents the refractive index of the liquid, represents the wavelength of the detection light.

9. The method for directionally manipulating micro-nano particles on the liquid surface according to claim 8, wherein By moving the third reflector, the incident position of the detection light on the interface between the liquid and the air is changed, and interference fringes at different positions on the interface between the liquid and the air are obtained.

10. The method for directionally manipulating micro-nano particles on the liquid surface according to claim 8, wherein The spot shape of the pump light is adjusted by a circular angular momentum phase plate or a spatial light modulator, and the energy of the pump light is adjusted by the pump light laser to change the shape of the protrusion.

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