CN105116534A - Method for capturing and screening particle above topological insulator substrate in tunable manner through linearly-polarized planar optical wave - Google Patents

Abstract

The invention provides a method for tunable trapping and screening of particles above a topological insulator substrate by linearly polarized plane light waves, which destroys the symmetrical distribution of the Poynting vectors around the particles, so that the total Poynting vectors on the particles are not zero , produce non-gradient optical force; then, by changing the quantum state of the topological insulator substrate plate, change the direction and magnitude of the total Poynting vector on the particle, and then change the non-gradient optical force of the total Poynting vector on the particle The direction and size of the particles are used to control the trajectory of the particles in the incident light field, so as to perform tunable capture and screening of nanometer-sized molecules attached to the surface of the particles. Among them, the reversible quantum phase transition of the topological insulator substrate plate from topological non-trivial to topological mediocre is realized by means of illumination, electrification, heating, pressurization, and external magnetic field.

Description

Tunable Trapping and Screening of Particles Over Topological Insulator Substrates by Linearly Polarized Plane Lightwaves

technical field

The invention relates to a method for tunable trapping and screening of particles above a topological insulator substrate by linearly polarized plane light waves, which can be applied to the fields of biology, medicine, nanometer manipulation and the like.

Background technique

Optical trapping and screening of tiny objects has always been a research hotspot in the field of optics. Optical gradient force plays an important role in various optical trapping technologies, such as optical tweezers and optical bundling through optical gradient force. However, optical gradient forces have the disadvantages of complex devices, non-tunable devices, and difficulty in trapping and screening nanometer-sized molecules. In 2008, Ward, T.J. et al proposed that the optical gradient force generated by circularly polarized light can capture and separate chiral molecules with nanometer size. However, the circularly polarized incident light still needs to be generated by complex equipment, which is not conducive to the practical application of the system; and the nano-sized molecules captured and separated must have a chiral structure, thus limiting the scope of its target. Therefore, the present invention proposes to cover the surface of the particle above the topological insulator substrate plate with nano-sized molecules, so that it can generate non-gradient optical force around the particle under the irradiation of linearly polarized plane light waves; The characteristics of electric field, temperature field, pressure field, and magnetic field change, tune the size and direction of the non-gradient optical force on the particles above the topological insulator substrate plate, so as to realize the capture and screening of nanometer-sized molecules attached to the surface of the particles, Wherein the nano-sized molecule can be an achiral structure.

Contents of the invention

The purpose of the present invention is to overcome the complexity of the incident light source (that is, the incident light must be circularly polarized or elliptically polarized) and the limitation of the screening object (that is, the nanoscale molecule must have chiral structure), the gradient optical force generated by circularly polarized or elliptically polarized light is not tunable, and it is difficult to capture nano-sized achiral molecules, etc., and provide a system with simple system, convenient operation, ultra-sensitive, ultra-fast, The non-gradient optical force generated by linearly polarized plane light waves, which has the advantages of active tuning, traps and screens achiral nanometer-sized molecules above the topological insulator substrate plate, which can be used in the fields of biology, medicine, and nanomanipulation.

A method for tunable trapping and screening of particles above a topological insulator substrate by a linearly polarized plane light wave, placing the particle above a topological insulator substrate slab that breaks the Poynting vector symmetry around the particle distribution, so that the total Poynting vector on the particle is not zero, resulting in non-gradient optical force; by changing the quantum state of the topological insulator substrate plate, changing the distribution of the total Poynting vector on the particle, and then changing the total Poynting vector The direction and magnitude of the non-gradient optical force acting on the particle can be used to control the trajectory of the particle in the incident light field, so as to perform tunable trapping and screening of nanometer-sized molecules attached to the surface of the particle, where the particle is placed in a topological insulator Above the substrate plate, the particle material can be medium or metal, the length, width and height of the topological insulator substrate are from 10 nanometers to 10 meters, and the distance between the particles and the surface of the topological insulator substrate plate is l (l>0); The shape can be a curved surface geometry such as a sphere, a cylinder, a cone, or a polyhedron such as a prism, a cube, and a cuboid, and the volume is between 1 cubic nanometer and 1000 cubic micrometers.

The incident light is a linearly polarized plane wave; the incident direction of the incident light is parallel to the topological insulator substrate plate, the frequency range is 0.3 microns to 20 microns, and the power range is 0.1 mW/μm ² to 10 mW/μm ² .

The light source of the incident light adopts a wavelength-tunable laser, a semiconductor continuous or quasi-continuous laser, or a light emitting diode.

The surface is attached with particles of nanometer size molecules, the particle material can be metal or medium, wherein the metal can be Al, Ag, Au, Cu, Ni, Pt, etc., and the medium can be semiconductor materials such as Si, SiO ₂ , GaAs , InP, Al ₂ O ₃ , etc. or polymers.

As for the topological insulator substrate flat plate, the topological insulator may be Bi _x Sb _1-x , HgTe, Bi ₂ Te ₃ , Bi ₂ Se ₃ or Sb ₂ Te ₃ .

Said particles with nano-sized molecules attached to the surface, the nano-sized molecules may have achiral structure or chiral structure, such as antigens, antibodies, enzymes, hormones, amines, peptides, amino acids, vitamins and the like.

In the topological insulator substrate flat plate, the topological insulator is realized through material growth processes, including magnetron sputtering, electron beam evaporation, chemical vapor deposition of metal organic compounds, vapor phase epitaxy growth, molecular beam epitaxy, and the like.

The topological insulator substrate flat plate can realize the reversible quantum phase transition of the topological insulator from topological non-trivial to topological mediocre by means of illumination, electrification, heating, pressurization, and external magnetic field.

The system of the invention consists of a light source, a microscope and an optical force display. Before the test, the topological insulator substrate plate is placed at the bottom of the sample pool filled with water or oil, and then the particles with nanometer-sized molecules on the surface are placed in the sample pool filled with water or oil, and placed on the topological insulator substrate at the same time. Above the plate, a linearly polarized plane wave light source enters from the side wall of the sample cell to irradiate the particles. Since the topological insulator substrate plate destroys the symmetrical distribution of the Poynting vectors around the particles, the total Poynting vector on the particles is not zero, resulting in Non-gradient optical force; then, by changing the quantum state of the topological insulator in the topological insulator substrate slab, changing the distribution of the total Poynting vector on the particle surface above the topological insulator substrate slab, and then changing the total Poynting vector acting on the particle The direction and magnitude of the non-gradient optical force are used to control the movement trajectory of the particle in the incident light field, so that the nanometer-sized molecules attached to the surface of the particle can be tunably captured and screened. Microscopes can be used to observe the trajectory of particles with nanometer-sized molecules attached to their surfaces under the action of incident light. The microscope can be an ordinary fluorescence vertical or upright microscope.

The system can realize tunable trapping and screening of objects with nanometer-sized achiral structures through simple linearly polarized plane light waves. It overcomes the complexity of the incident light source (that is, the incident light must be circularly polarized or elliptically polarized), the limitation of the screening object (that is, the nanoscale molecule must have chirality), The gradient optical force generated by circularly polarized or elliptically polarized light is not tunable, and it is difficult to capture nanometer-sized molecules. It has the advantages of simple system, convenient operation, ultra-sensitivity, ultra-fast, active tuning, etc. It can be used in biology, medicine and nanomanipulation and other fields.

Description of drawings

Figure 1 is a schematic diagram of particles with nanometer-sized molecules attached to their surfaces.

Fig. 2 is a schematic diagram of the process of trapping and screening particles with nanometer-sized molecules on the surface above the topological insulator substrate plate by non-gradient optical force generated by linearly polarized light.

Fig. 3 is a schematic diagram of a test system for trapping and screening particles with nanometer-sized molecules on the surface above a topological insulator substrate plate by non-gradient optical force generated by linearly polarized light.

In the figure: 1 microparticle, 2 nanometer size molecule, 3 topological insulator substrate plate, 4 light source, 5 microscope, 6 optical force display, 7 sample cell, 8 temperature controller, 9CCD camera, 10 monitor, 11 computer, 12 video recorder .

Detailed ways

In order to make the content of the technical solution of the present invention clearer, the specific implementation manners of the present invention will be described in detail below in combination with the technical solution and the accompanying drawings. The material growth techniques include: magnetron sputtering, electron beam evaporation, chemical vapor deposition of metal-organic compounds, vapor phase epitaxy, and molecular beam epitaxy.

Example 1

First, particles 1 are produced through a material growth process, as shown in Fig. 1(a). The geometric shape and size of particles can be determined by finite time domain difference method, finite element method and other algorithms.

Secondly, nanometer-sized molecules 2 are attached to the outer surface of the particle 1, as shown in FIG. 1(b).

Then, the particles 1 with nanometer-sized molecules 2 attached to the surface are placed above the surface of the topological insulator substrate 3 at a distance of l (l>0). When the incident light is a linearly polarized plane wave and the topological insulator substrate 3 is topologically nontrivial When solid, the Poynting vector around the particle 1 above the topological insulator substrate plate 3 is asymmetrically distributed, that is, the total Poynting vector on the particle 1 is not zero, resulting in a non-gradient pointing to the right front along the incident light direction The optical force makes the particle 1 move along the right front of the incident light direction, and then drives the nano-sized molecules 2 attached to the surface of the particle 1 to move along the right front of the incident light direction, as shown in Figure 2(a).

Afterwards, the topologically non-banal body of the topological insulator substrate plate 3 is converted into a topologically mediocre body by means of light, electricity, heating, pressurization, and an external magnetic field (that is, the topological insulator produces a quantum state change from topologically non-banal to topologically mediocre) , so that the direction and size of the total Poynting vector on the surface of particle 1 are changed, producing a non-gradient optical force pointing to the front left along the direction of incident light, so that particle 1 drives the nanometer-sized molecules 2 attached to its surface to the left along the direction of incident light Front movement, as shown in accompanying drawing 2 (b).

Finally, the topological insulator substrate plate 3 is changed from a topologically mediocre body to a topologically non-meaningful body by means of cooling, lighting, etc. The gradient optical force changes back to the non-gradient optical force pointing to the right front along the incident light direction, and the particle 1 drives the nanometer-sized molecule 2 to move along the right front direction of the incident light direction, as shown in Figure 2(c).

In this way, by changing the quantum state of the topological insulator in the topological insulator substrate plate 3, we control the trajectory of the particle 1 in the incident light field, and finally realize the tunable capture and screening of the nanometer-sized molecules 2 attached to the surface of the particle 1.

The system of the present invention is mainly composed of a light source 4 , a microscope 5 and an optical force display 6 . Before the test, the topological insulator substrate plate 3 is placed at the bottom of the sample pool 7 filled with water or oil, and then the particles 1 with nanometer-sized molecules 2 attached to the surface are placed in the sample pool 7 and placed on the topological insulator substrate plate 3 above. The light source 4 generates a linearly polarized plane wave that enters from the side wall of the sample cell 7 and irradiates the particle 1 horizontally, so as to capture and manipulate the particle 1 attached to the surface of the nanometer-sized molecule 2 . The microscope 5 can be used to observe the trajectory of the microparticles 1 attached to the nanometer-sized molecules 2 on the microsurface under the action of incident light. The non-gradient optical force produced by the linearly polarized plane wave attached to the surface of the particle 1 with nanometer-sized molecules 2 is measured by the optical force display 6 . The system of the present invention also includes temperature controller 8, CCD camera 9, monitor 10, computer 11, and video recorder 12 etc. (shown in accompanying drawing 3) simultaneously. The CCD camera 9 is used for real-time monitoring of the particles 1 with nanometer-sized molecules 2 attached to the surface irradiated by the linearly polarized plane wave, and the obtained video signal is displayed on the monitor. Video recorder 12 may be used to record images. The sample pool 7 is connected to the temperature controller 8 , and the quantum state of the topological insulator in the topological insulator substrate plate 3 changes with the temperature of the sample pool 7 . The computer 11 can store the field of view information collected by the microscope 5 .

The above are the technical principles and specific examples of the application of the present invention. The equivalent transformation done according to the concept of the present invention, as long as the scheme used does not exceed the spirit covered by the description and drawings, shall be included in the present invention. Within the scope, it is hereby explained.

Claims (8)

1. a plane of linear polarization light wave is to the tunable method of catching and screening being in topological insulator types of flexure particulate, it is characterized in that, particulate is placed in above topological insulator substrate flat board, the Poynting vector that this topological insulator substrate flat board destroys around particulate is symmetrical, make the total Poynting vector on particulate non-vanishing, produce non-gradient optical force, by changing the quantum state of topological insulator substrate flat board, change the total Poynting vector distribution on particulate, and then change direction and the size that total Poynting vector acts on the non-gradient optical force on particulate, regulate and control the movement locus of particulate in incident field, thus carry out tunablely catching and screening to the nanometer-size molecular being attached to microparticle surfaces, wherein, particulate is placed in above topological insulator substrate flat board, microparticle material can be medium or metal, the length of topological insulator substrate, wide, high in 10 nanometers to 10 meters, the distance of particulate and topological insulator substrate planar surface is l, l>0, the profile of particulate is surface geometry body or polyhedron, and volume is at 1 cubic nanometer to 1000 cu μ m.

2. method according to claim 1, is characterized in that, incident light is plane of linear polarization ripple; It is dull and stereotyped that incident light beam strikes direction is parallel to topological insulator substrate, and frequency range is 0.3 micron ~ 20 microns, and power bracket is 0.1mW/ μm ²~ 10mW/ μm ².

3. method according to claim 1 and 2, is characterized in that, the light source of incident light adopts Wavelength tunable laser, semiconductor continuously or quasi-continuous lasing or light emitting diode.

4. method according to claim 3, is characterized in that, microparticle material is metal or medium, and wherein, metal is Al, Ag, Au, Cu, Ni, Pt, and medium is Si, SiO ₂, GaAs, InP, Al ₂o ₃in one or polymkeric substance.

5. method according to claim 4, is characterized in that, topological insulator is Bi _xsb _1-x, HgTe, Bi ₂te ₃, Bi ₂se ₃or Sb ₂te ₃.

6. the method according to claim 1 or 2 or 4 or 5, it is characterized in that, nanometer-size molecular has achirality structure or chiral structure.

7. the method according to claim 1 or 2 or 4 or 5, it is characterized in that, topological insulator is realized by Material growth technique, comprises magnetron sputtering, electron beam evaporation, metal organic compound chemical gaseous phase deposition, vapor phase epitaxial growth, molecular beam epitaxy.

8. the method according to claim 1 or 2 or 4 or 5, is characterized in that, realizes topological insulator from the non-mediocrity of topology to the reversible quantum phase transitions of topology mediocrity by modes such as illumination, energising, heating, pressurization and externally-applied magnetic fields.