Photoelectric tweezers device for dielectric particle control

Abstract

The invention discloses a photoelectric tweezers device for dielectric particle control, which relates to the technical field of photoelectric tweezers and comprises an ultraviolet laser microscope light path, an ultraviolet laser sheet illumination light path, an imaging light path and a dielectric particle control chip module. The dielectric particle control chip module comprises a first lithium niobate wafer, a second lithium niobate wafer and a motion control device; the ultraviolet laser microscope light path irradiates the first lithium niobate wafer, and the ultraviolet laser sheet-shaped illumination light path irradiates the second lithium niobate wafer; the first lithium niobate wafer and the second lithium niobate wafer respectively generate light-excited electrons after being irradiated; the light-excited electrons generate laser converging light spots; a laser convergence light spot generated by the first lithium niobate wafer is smaller than a laser convergence light spot generated by the second lithium niobate wafer; a non-uniform electric field is generated in the dielectric particle control chip; and the imaging light path is used for displaying particle information generated in the dielectric particle control chip module. The device is simple in structure, and the dielectric particles can be flexibly, efficiently and accurately controlled.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric tweezers, and more particularly to a photoelectric tweezers device for dielectric particle manipulation. Background Art

[0002] Optoelectronic tweezers (OET) is an emerging technology that uses the photoelectric effect to manipulate tiny objects (such as microspheres, particles, etc.). It is developed on the basis of traditional optical tweezers technology, combining the principles of optics and electrodynamics, and through the precise control of light beams and electric fields, it can achieve operations such as capturing, moving, rotating and sorting tiny objects. Relying on this light-induced electrodynamic effect, OET has great advantages in micromanipulation, such as programmability, flexibility, versatility, high throughput and easy integration with other characterization systems, so it has broad application prospects.

[0003] When optoelectronic materials (such as lithium niobate, lithium tantalate, etc.) are used as substrates, the virtual electrodes of the photoelectric tweezers can be preserved for a long time in the dark area, and they can also be erased and reused by heating and uniform illumination. Therefore, in recent years, photoelectric tweezers based on lithium niobate have become a research hotspot at home and abroad. In 2001, Sarkisov captured polystyrene particles on x-cut iron-doped lithium niobate wafers. In 2011, Javier V et al. captured micron-sized calcium carbonate particles on the surface of y-cut lithium niobate crystals. In 2013, Esseling et al. successfully captured charged particles (hydrofluoroether and GC particles) on c-cut lithium niobate wafers to achieve high-quality two-dimensional particle capture patterns. In 2015, Munoz-Martinez et al. immersed the laser-irradiated c-cut lithium niobate wafer into dielectric particles (Ca 2 CO 3 ) solution, and successfully obtained a two-dimensional particle capture pattern. In 2017, Chen et al. used a single laser beam to study the dynamic dielectrophoresis behavior of insulating oil microdroplets on a double C-cut lithium niobate device. At present, the research on photoelectric tweezers is relatively in-depth and extensive, but there is still little research on flexible and efficient manipulation of dielectric particles. The existing two-dimensional manipulation of dielectric particles mostly involves only a single capture pattern, and flexible manipulation cannot be achieved. In addition, current research is mainly based on a single lithium niobate wafer and a single laser beam. Since the electric field of a single piece of lithium niobate is divergent, this greatly affects the manipulation efficiency and manipulation accuracy of the particles. Therefore, designing an optoelectronic tweezer device for dielectric particle manipulation to achieve flexible, efficient and precise manipulation of dielectric particles is a problem that technicians in this field urgently need to solve. Summary of the invention

[0004] In view of this, the present invention provides a photoelectric tweezers device for dielectric particle manipulation, which can achieve flexible, efficient and precise manipulation of dielectric particles.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] An optoelectronic tweezers device for dielectric particle manipulation, comprising: an ultraviolet laser microscope optical path, an ultraviolet laser sheet illumination optical path, an imaging optical path, and a dielectric particle manipulation chip module;

[0007] The dielectric particle manipulation chip module includes a first lithium niobate chip, a second lithium niobate chip and a three-dimensional motion control device;

[0008] The ultraviolet laser microscope light path illuminates the first lithium niobate wafer, and the ultraviolet laser sheet illumination light path illuminates the second lithium niobate wafer; the first lithium niobate wafer and the second lithium niobate wafer respectively generate photoexcited electrons after being irradiated; the photoexcited electrons generate a laser convergence spot;

[0009] The laser convergence spot generated by the first lithium niobate wafer is smaller than the laser convergence spot in the second lithium niobate wafer; an inhomogeneous electric field is generated in the dielectric particle manipulation chip module;

[0010] The imaging optical path is used to display the particle information generated in the dielectric particle manipulation chip module.

[0011] Preferably, the ultraviolet laser microscope optical path includes:

[0012] a first laser, a first beam expansion system, a dichroic mirror, and a microscope objective;

[0013] The laser emitted by the first laser generates a first incident laser through a first beam expansion system;

[0014] The first incident laser is totally reflected by the dichroic mirror to the microscope objective lens;

[0015] The microscope objective lens focuses the first incident laser onto the upper surface of the first lithium niobate wafer.

[0016] Preferably, the ultraviolet laser sheet illumination light path includes:

[0017] A second laser, a second beam expansion system, an adjustable slit, and a converging lens;

[0018] The second laser emitted by the second laser generates a second incident laser through a second beam expansion system;

[0019] The center point of the adjustable slit coincides with the main optical axis of the second laser, so as to control the irradiation power of the second incident laser;

[0020] The converging lens always converges the second incident laser inside the second lithium niobate wafer, and the converging point is located right above the laser focus generated by the microscope objective lens.

[0021] Preferably, the imaging light path includes an illuminator, a filter and a CMOS camera;

[0022] The illuminator is used to provide light source for the imaging light path;

[0023] The filter is used to filter out laser light and provide high transmission of the light from the lighting lamp;

[0024] The CMOS camera can image the image on the focal plane collected by the microscope objective lens onto the detection surface of the CMOS camera.

[0025] Preferably, the first incident laser is used to fill the microscope objective; the dichroic mirror is placed at a 45° angle to the first incident laser, and is used to totally reflect the first incident laser band and highly transmit the light of the illumination lamp; the optical axis of the microscope objective coincides with the main optical axis of the first incident laser, and the laser is converged on the upper surface of the first lithium niobate wafer.

[0026] Preferably, the incident light beam is used to fill an adjustable slit, the long side of the adjustable slit is parallel to the upper / lower surface of the second lithium niobate wafer, and the adjustable slit controls the irradiation power of the second laser by adjusting the width.

[0027] Preferably, in the dielectric particle manipulation chip module, the focal plane of the microscope objective lens coincides with the upper surface of the first lithium niobate wafer;

[0028] The laser convergence spot area obtained by focusing the microscope objective lens is always smaller than the laser convergence spot area in the second lithium niobate wafer.

[0029] The three-dimensional motion device is used to quasi-control the interlayer spacing and relative position of the dielectric particle manipulation chip module;

[0030] The first lithium niobate wafer and the second lithium niobate wafer are both c-cut iron-doped lithium niobate wafers. The two lithium niobate wafers are placed in parallel and have the same polarization axis direction.

[0031] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a photoelectric tweezers device for dielectric particle manipulation, and the beneficial technical effects are:

[0032] (1) The photoelectric tweezers device proposed in the present invention includes two layers of c-cut iron-doped lithium niobate wafers and two induced laser beams. The lithium niobate crystals are all iron-doped lithium niobate. The addition of iron impurities will introduce additional energy levels in the lithium niobate lattice, increase the concentration of photogenerated carriers and the intensity of the built-in electric field, thereby improving the efficiency of photovoltaics; and the lithium niobate wafers are all placed in parallel and have the same polarization axis direction. When the two laser beams are focused on the upper and lower lithium niobate wafers respectively, the -c surface of the wafer is positively charged and the +c surface is negatively charged, thereby forming two electric field sources distributed up and down and with opposite positive and negative directions in the chip. Compared with the common single-piece c-cut lithium niobate that generates a surface divergent electric field, this control device converges the electric field into a beam, which can effectively improve the efficiency of optical control. In addition, compared with the optical path device induced by a single laser beam, this control device can focus the laser on two lithium niobate wafers respectively, fully inducing them to generate photoexcited electrons, significantly shortening the optical control response time.

[0033] (2) The present invention proposes to use two laser beams to ultimately produce two light spots of different sizes. The upper laser beam is converged by a slit and a converging lens, and the lower laser beam is converged by a microscope objective. Since a microscope objective can converge lasers more effectively than an ordinary convex lens in general, the excitation range of the upper lithium niobate crystals is more dispersed, and the charge density generated is also lower. The excitation range of the lower lithium niobate crystals is more concentrated, and the charge density generated is also higher, thereby forming an inhomogeneous electric field in the chip interlayer. Dielectric particles will be affected by the dielectrophoretic force in the inhomogeneous electric field, thereby achieving efficient particle manipulation, and the excitation range of the lower lithium niobate is smaller, which can effectively improve the accuracy of light manipulation.

[0034] (3) The present invention proposes to use a three-dimensional motion control device to accurately control the interlayer spacing and spatial position of the lithium niobate chip. During the control process, the laser is fixed, and the chip can move along the planned path in the x-axis and y-axis directions. The particles respond faster at the laser irradiation point, and the charge here does not disappear immediately after the laser leaves. The particles can be captured on the lower surface of the chip along the path where the laser irradiates, thereby achieving flexible particle control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the structure of the photoelectric tweezers device provided by the present invention;

[0037] Figure 2 A schematic diagram of the electric field generated by two horizontally placed c-cut iron-doped lithium niobate sheets (+c face upward) under laser irradiation provided by an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of a polystyrene microsphere particle provided in an embodiment of the present invention being polarized in a non-uniform electric field and subjected to dielectrophoretic force.

[0039] In the figure: 1-1 the first ultraviolet laser, 1-2 the first lens, 1-3 the second lens, 1-4 the dichroic mirror, 1-5 the microscope objective lens, 1-6 the lighting lamp, 1-7 the filter, 1-8 the CMOS camera, 2-1 the second ultraviolet laser, 2-2 the third lens, 2-3 the fourth lens, 2-4 the adjustable slit, 2-5 the converging lens, 3-1 the first iron-doped lithium niobate wafer, 3-2 the second iron-doped lithium niobate wafer, 3-3 the three-dimensional motion control device. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 As shown, an embodiment of the present invention discloses an optoelectronic tweezers device for dielectric particle manipulation, comprising: an ultraviolet laser microscope optical path, an ultraviolet laser sheet illumination optical path, an imaging optical path, and a dielectric particle manipulation chip module;

[0042] The dielectric particle manipulation chip module includes a first lithium niobate chip 3-1, a second lithium niobate chip 3-2 and a three-dimensional motion control device 3-3;

[0043] The ultraviolet laser microscope light path illuminates the first lithium niobate wafer 3-1, and the ultraviolet laser sheet illumination light path illuminates the second lithium niobate wafer 3-2; the first lithium niobate wafer 3-1 and the second lithium niobate wafer 3-2 generate photoexcited electrons after being irradiated; the photoexcited electrons generate laser convergence spots;

[0044] The laser convergence spot generated by the first lithium niobate wafer 3-1 is smaller than the laser convergence spot generated by the second lithium niobate wafer 3-2; an uneven electric field is generated in the dielectric particle manipulation chip module;

[0045] The imaging optical path is used to display the particle information generated in the dielectric particle manipulation chip module.

[0046] Furthermore, in an embodiment of the present invention, ultraviolet lasers are used in the ultraviolet laser microscope optical path and the ultraviolet laser sheet illumination optical path. When the lithium niobate wafer is irradiated by two beams of ultraviolet lasers, photoexcited electrons are generated due to the photovoltaic effect. Moreover, the laser convergence spot in the first lithium niobate wafer 3-1 is smaller than the laser convergence spot in the second lithium niobate wafer 3-2. Therefore, an uneven electric field is generated in the control chip, thereby realizing directional control of dielectric particles.

[0047] Specifically, the ultraviolet laser microscope optical path includes:

[0048] A first laser 1-1, a first beam expansion system, a dichroic mirror 1-4 and a microscope objective 1-5;

[0049] The laser emitted by the first laser 1-1 generates a first incident laser through a first beam expansion system;

[0050] The first incident laser is totally reflected by the dichroic mirror 1-4 to the microscope objective 1-5;

[0051] The microscope objective lens 1-5 focuses the first incident laser onto the upper surface of the first lithium niobate wafer 3-1.

[0052] Specifically, the ultraviolet laser sheet illumination light path includes:

[0053] A second laser 2-1, a second beam expansion system, an adjustable slit 2-4, and a converging lens 2-5;

[0054] The second laser emitted by the second laser 2-1 generates a second incident laser through a second beam expansion system;

[0055] The center point of the adjustable slit 2-4 coincides with the main optical axis of the second laser, so as to control the irradiation power of the second incident laser;

[0056] The converging lens 2-5 always converges the second incident laser inside the second lithium niobate wafer 3-2, and the convergence point is located directly above the laser focus generated by the microscope objective lens 1-5.

[0057] Furthermore, the first beam expansion system selected in the embodiment of the present invention includes a convex lens 1-2 and a convex lens 1-3; the second beam expansion system includes a convex lens 2-2 and a convex lens 2-3.

[0058] Specifically, the imaging light path includes an illuminator 1-6, a filter 1-7 and a CMOS camera 1-8;

[0059] Illumination lamps 1-6 are used to provide light sources for the imaging light path;

[0060] The filter 1-7 is used to filter out laser light and provide high transmission for the light of the lighting lamp 1-6;

[0061] The CMOS camera 1-8 can image the image on the focal plane collected by the microscope objective lens 1-5 onto the detection surface of the CMOS camera 1-8.

[0062] Furthermore, the CMOS camera 1-8 in the embodiment of the present invention is an infinite imaging camera, and the image on the focal plane collected by the microscope objective lens 1-5 can be imaged onto the camera detection surface, thereby realizing simultaneous particle manipulation and observation.

[0063] Specifically, the first incident laser is used to fill the microscope objective 1-5; the dichroic mirror 1-4 is placed at a 45° angle to the first incident laser, and is used to totally reflect the first incident laser band and highly transmit the light of the illumination lamp 1-6; the optical axis of the microscope objective 1-5 coincides with the main optical axis of the first incident laser, and converges the laser on the upper surface of the first lithium niobate wafer 3-1.

[0064] Specifically, the second incident laser is used to fill the adjustable slit 2-4, the long side of the adjustable slit 2-4 is parallel to the upper / lower surface of the second lithium niobate wafer 3-2, and the adjustable slit 2-4 controls the irradiation power of the second laser 2-1 by adjusting the width.

[0065] Specifically, in the dielectric particle manipulation chip module, the focal plane of the microscope objective lens 1-5 coincides with the upper surface of the first lithium niobate crystal 3-1;

[0066] The laser convergence spot area obtained by focusing the microscope objective lens 1-5 is always smaller than the laser convergence spot area in the second lithium niobate wafer 3-2.

[0067] The three-dimensional motion device 3-3 is used to quasi-control the interlayer spacing and relative position of the dielectric particle manipulation chip module;

[0068] The first lithium niobate wafer 3 - 1 and the second lithium niobate wafer 3 - 2 are both c-cut iron-doped lithium niobate wafers. The two lithium niobate wafers are placed in parallel with the same polarization axis direction.

[0069] Furthermore, in the embodiment of the present invention, the focal plane of the microscope objective 1-5 coincides with the upper surface of the first lithium niobate wafer 3-1; the laser convergence spot area obtained by focusing the microscope objective 1-5 is always smaller than the laser convergence spot area in the second lithium niobate wafer 3-2. When the ultraviolet laser irradiates the c-cut iron-doped lithium niobate wafer, a large number of photoexcited electrons moving along the c-axis are generated inside the wafer, making the -c surface of the lithium niobate wafer positively charged and the +c surface negatively charged, thereby generating two electric field sources distributed up and down and with opposite positive and negative in the control chip. Since the illumination area on the first lithium niobate wafer 3-1 is small and the illumination area on the second lithium niobate wafer 3-2 is large, an inhomogeneous electric field is generated between the first lithium niobate wafer 3-1 and the second lithium niobate wafer 3-2. The dielectric particles are driven by the dielectrophoretic force generated by the inhomogeneous electric field to achieve directional motion, thereby achieving the purpose of precise particle control.

[0070] The expression of the dielectrophoretic force on dielectric particles in the non-uniform electric field is:

[0071]

[0072] Where r is the particle radius, ε m is the dielectric constant of the medium, α(ω) is the Klausius-Mossotti factor, is the gradient of the square of the electric field intensity, reflecting the degree of non-uniformity of the electric field;

[0073] The expression of α(ω) is:

[0074]

[0075] Here the formula ε * is a unified expression for the complex dielectric constant, where j is an imaginary unit, σ is the conductivity, and ω is the angular frequency of the electric field. They refer to the complex dielectric constants of particles and media, respectively, and their expressions are similar to ε * The form is the same; for easier understanding, it can also be written directly as In the present invention, a laser is used to irradiate a lithium niobate substrate, with an angular frequency of ω→0, ε * The imaginary part of approaches infinity, so the expression of dielectrophoretic force is:

[0076]

[0077] In the formula, σ p and σ m represent the electrical conductivity of particles and medium respectively.

[0078] It can be seen that the positive and negative of Re[α(ω)] is determined by σ p and σm The difference between p Greater than σ m When Re[α(ω)] is positive, F EDP is positive, the particle is attracted; on the contrary, when σ p Less than σ m When Re[α(ω)] is negative, F EDP is negative, the particles experience a repulsive force.

[0079] In another embodiment of the present invention, taking polystyrene microspheres as manipulation particles and insulating oil as a buffer as an example, the working process of the particle manipulation photoelectric tweezers device of the present invention specifically includes the following steps:

[0080] Step 1: Fix two lithium niobate wafers horizontally on a three-dimensional motion control device, and make them both face up with +c (the conductivity of polystyrene microspheres is greater than that of insulating oil), take a proper amount of liquid medium containing uniform polystyrene particles, drop it on the surface of the first lithium niobate wafer 3-1, and adjust the spacing of the chip interlayer through the three-dimensional motion device 3-3;

[0081] Step 2: Start the ultraviolet laser 1-1, the incident laser is expanded by the beam expansion system composed of lenses 1-2 and 1-3, and then reflected by the dichroic mirror 1-4 to the microscope objective lens 1-5 to generate a convergent solid Gaussian spot, and focused on the upper surface of the first lithium niobate wafer 3-1;

[0082] Step 3: Start the ultraviolet laser 2-1, and the incident laser is expanded by the beam expansion system composed of lenses 2-2 and 2-3, and then converted into sheet illumination by the adjustable slit 2-4, and the power is adjusted. Then, the laser is focused on the second lithium niobate wafer 3-2 by the converging lens 2-5, and the position of the converging lens is adjusted so that the focus of the light spot on the second lithium niobate wafer is located directly above the focus of the light spot in the first lithium niobate wafer;

[0083] Step 4: If Figure 2 As shown in the figure, when the laser shines on the iron-doped lithium niobate wafers 3-1 and 3-2, the electrons inside them can easily move from the Fe 2+ / 3+ The excited electrons move along the positive direction (+c) of the polarization axis of lithium niobate, resulting in a large number of excited electrons gathering on the +c surface of the c-cut lithium niobate, while a large number of positive charges remain on the -c surface. In addition, due to the different spot sizes of the two induced lasers, a structure such as Figure 2 The inhomogeneous electric field shown;

[0084] Step 5: If Figure 3As shown, the polystyrene microspheres are polarized in the non-uniform electric field, resulting in the separation of positive and negative charges. The field strength where the positive charge is located is stronger, and the field strength where the negative charge is located is weaker. The forces at both ends of the polarization are not equal, and the resultant force is the dielectrophoretic force. In addition, the conductivity of the polystyrene microspheres is greater than the conductivity of the insulating oil. The polystyrene microspheres are captured at the first lithium niobate light spot under the action of the positive dielectrophoretic force.

[0085] Step 6: Adjust CMOS camera 1-8 to infinity imaging, image the image on the focal plane collected by the microscope objective lens onto the detection surface of CMOS camera 1-8, and clearly see the particle manipulation state in real time;

[0086] Step 7: Adjust the three-dimensional motion control device 3-3 to control the lithium niobate chip to move slowly along the set path, repeat steps 4 and 5, and the particles are continuously captured by the dielectrophoretic force to the laser irradiation point of the first lithium niobate chip, thereby showing a flexible form of particle manipulation.

[0087] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0088] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An optoelectronic tweezers device for dielectric particle manipulation, characterized in that: include: UV laser microscope optical path, UV laser sheet illumination optical path, imaging optical path and dielectric particle manipulation chip module; The dielectric particle manipulation chip module includes a first lithium niobate chip, a second lithium niobate chip and a three-dimensional motion control device; The ultraviolet laser microscope light path illuminates the first lithium niobate wafer, and the ultraviolet laser sheet illumination light path illuminates the second lithium niobate wafer; the first lithium niobate wafer and the second lithium niobate wafer respectively generate photoexcited electrons after being irradiated; the photoexcited electrons generate a laser convergence spot; The laser convergence spot generated by the first lithium niobate wafer is smaller than the laser convergence spot in the second lithium niobate wafer; an inhomogeneous electric field is generated in the dielectric particle manipulation chip module; The imaging optical path is used to display the particle information generated by the dielectric particle manipulation chip module.

2. The photoelectric tweezers device for dielectric particle manipulation according to claim 1, characterized in that: The ultraviolet laser microscope optical path includes: a first laser, a first beam expansion system, a dichroic mirror, and a microscope objective; The laser emitted by the first laser generates a first incident laser through a first beam expansion system; The first incident laser is totally reflected by the dichroic mirror to the microscope objective lens; The microscope objective lens focuses the first incident laser onto the upper surface of the first lithium niobate wafer.

3. The photoelectric tweezers device for dielectric particle manipulation according to claim 1, characterized in that: The ultraviolet laser sheet illumination optical path comprises: A second laser, a second beam expansion system, an adjustable slit, and a converging lens; The second laser emitted by the second laser generates a second incident laser through a second beam expansion system; The center point of the adjustable slit coincides with the main optical axis of the second laser, so as to control the irradiation power of the second incident laser; The converging lens always converges the second incident laser inside the second lithium niobate wafer, and the converging point is located right above the laser focus generated by the microscope objective lens.

4. The photoelectric tweezers device for dielectric particle manipulation according to claim 2, characterized in that: The imaging optical path includes an illuminator, a filter and a CMOS camera; The illuminator is used to provide a light source for the imaging light path; The filter is used to filter out laser light and provide high transmission for the illumination light wavelength band; The CMOS camera images the image on the focal plane collected by the microscope objective lens onto the detection surface of the CMOS camera.

5. The photoelectric tweezers device for dielectric particle manipulation according to claim 4, characterized in that: The first incident laser is used to fill the microscope objective lens; the dichroic mirror is placed at a 45° angle to the first incident laser, and is used to totally reflect the first incident laser and highly transmit the light of the illumination lamp; the optical axis of the microscope objective lens coincides with the main optical axis of the first incident laser, and the laser is converged on the upper surface of the first lithium niobate wafer.

6. The photoelectric tweezers device for dielectric particle manipulation according to claim 3, characterized in that: The second incident laser is used to fill the adjustable slit, the long side of the adjustable slit is parallel to the upper / lower surface of the second lithium niobate wafer, and the adjustable slit controls the irradiation power of the second incident laser by adjusting the width.

7. The photoelectric tweezers device for dielectric particle manipulation according to claim 2, characterized in that: In the dielectric particle manipulation chip module, the focal plane of the microscope objective lens coincides with the upper surface of the first lithium niobate wafer; The laser convergence spot area obtained by focusing the microscope objective lens is always smaller than the laser convergence spot area in the second lithium niobate wafer. The three-dimensional motion device is used to quasi-control the interlayer spacing and relative position of the dielectric particle manipulation chip module; The first lithium niobate wafer and the second lithium niobate wafer are both c-cut iron-doped lithium niobate wafers. The two lithium niobate wafers are placed in parallel and have the same polarization axis direction.

Images