Low-refractive-index particle size sorting method and device based on perfect vortex light

Abstract

The invention discloses a low-refractive-index particle size sorting method and device based on perfect vortex light. The method comprises the following steps that a solution containing low-refractive-index particles is placed in a sample pool; a plurality of perfect vortex light beams are focused at a sample cell to form a double-ring perfect vortex light field; the double-ring perfect vortex light field is provided with an inner ring light field and an outer ring light field, and a sorting channel is formed between the inner ring light field and the outer ring light field; the low-refractive-index particles move between the inner ring light field and the outer ring light field under the driving action of the phase gradient force; the low-refractive-index particles move to the sorting channel, the large-size low-refractive-index particles enter the inner ring light field under the action of inward light force, and meanwhile, the small-size low-refractive-index particles meeting the stable capturing condition continue to move on the double-ring perfect vortex light field after passing through the sorting channel, so that sorting is completed; according to the method, the low-refractive-index particles with different sizes can be separated into different areas to finish sorting only by virtue of a light force effect generated by a double-ring perfect vortex light field in a sample pool on the particles.

Description

Technical Field

[0001] This invention relates to the field of particle micromanipulation technology, specifically to a method and apparatus for sorting low-refractive-index particles based on perfect vortex light. Background Technology

[0002] While optical tweezers have achieved significant results in the manipulation of high-refractive-index particles, research on low-refractive-index particles has been limited due to the difficulty in achieving stable manipulation. However, it is worth noting that the precise manipulation of low-refractive-index microparticles holds great promise for applications such as yeast cells, liposomes, and droplets. These applications highlight the enormous potential of low-refractive-index microparticles in optical tweezers and underscore the urgent need for further exploration of their properties and applications.

[0003] Currently, the flexible manipulation of low-refractive-index particles involves multiple challenges. On the one hand, due to the difficulty in capturing low-refractive-index particles caused by their repulsion by light, traditional optical tweezers use single-beam dark traps to manipulate the particles, such as higher-order Bessel beams and vortex beams. However, these traditional methods rely on a single capture method, resulting in insufficient flexibility and low manipulation efficiency. On the other hand, due to their repulsion by light, the sorting of low-refractive-index particles places strict requirements on the optical field; high-resolution sorting requires precise optical field design and implementation. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for sorting low-refractive-index particles based on perfect vortex light. This method can separate low-refractive-index particles of different sizes into different regions by relying solely on the photodynamic effect of the double-ring perfect vortex light field in the sample cell.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for sorting low-refractive-index particles based on perfect vortex light, comprising the following steps: The solution containing low-refractive-index microparticles is placed in the sample cell; Multiple perfect vortex beams are focused at the sample cell to form a double-ring perfect vortex light field to irradiate low refractive index particles; The dual-ring perfect vortex optical field has an inner ring optical field and an outer ring optical field, and the spacing between the inner ring optical field and the outer ring optical field is continuously reduced at least locally to form a sorting channel; The low-refractive-index particles in the double-ring perfect vortex optical field move between the inner and outer ring optical fields under the driving force of the phase gradient force. When the low-refractive-index particles move to the sorting channel, the larger low-refractive-index particles are subjected to inward optical force and enter the interior of the inner ring light field, while the smaller low-refractive-index particles that meet the stable capture conditions continue to move between the inner ring light field and the outer ring light field after passing through the sorting channel.

[0006] In the low refractive index particle size sorting method based on perfect vortex light provided in at least one embodiment of this disclosure, the outer ring light field is a perfect vortex light field with a positive circular ring curve. The left half of the inner ring light field is a perfect vortex light field with a semi-circular ring curve, and the right half of the inner ring light field is a perfect vortex light field with a semi-elliptical ring curve.

[0007] In at least one embodiment of the present disclosure, the low-refractive-index microparticles are hollow glass spheres, which are sorted by the size of low-refractive-index microparticles based on perfect vortex light.

[0008] In at least one embodiment of the present disclosure, the low-refractive-index microparticle size sorting method based on perfect vortex light provides a low-refractive-index microparticle with a radius of 3-6 μm.

[0009] Secondly, the present invention also provides a low-refractive-index particle size sorting device based on perfect vortex light, comprising: a sample cell and a modulated light source module.

[0010] The sample cell is used to contain a solution of low-refractive-index microparticles to be sorted.

[0011] The modulated light source module is used to generate a double-ring perfect vortex light field to sort low-refractive-index particles in the sample cell.

[0012] The dual-ring perfect vortex optical field has an inner ring optical field and an outer ring optical field, and the spacing between the inner ring optical field and the outer ring optical field is continuously reduced at least locally to form a sorting channel.

[0013] The low-refractive-index particles in the double-ring perfect vortex light field move between the inner and outer ring light fields under the driving force of the phase gradient force.

[0014] When the low-refractive-index particles move to the sorting channel, the larger low-refractive-index particles are subjected to inward optical force and enter the interior of the inner ring light field, while the smaller low-refractive-index particles that meet the stable capture conditions continue to move between the inner ring light field and the outer ring light field after passing through the sorting channel.

[0015] In at least one embodiment of the present disclosure, a low-refractive-index particle size sorting device based on perfect vortex light is provided, wherein the modulated light source module includes: a laser emission component, a beam modulation component, and a focusing component.

[0016] The laser emission assembly is used to generate a laser beam.

[0017] The beam modulation component is used to modulate and shape the laser beam.

[0018] The focusing component is used to focus the laser emitted from the beam modulation component to form the double-ring perfect vortex light field in the sample cell.

[0019] The low-refractive-index particle size sorting device based on perfect vortex light provided in at least one embodiment of this disclosure further includes: an imaging module for capturing images of the sorting process of the low-refractive-index particles.

[0020] In at least one embodiment of the low-refractive-index particle size sorting device based on perfect vortex light provided in this disclosure, the wavelength of the laser beam is 1064 nm.

[0021] The low-refractive-index particle size sorting device based on perfect vortex light provided in at least one embodiment of this disclosure further includes: an illumination component for providing white light to illuminate the sample cell.

[0022] The beneficial effects of this invention are as follows: A unique double-ring perfect vortex light field is constructed using multiple perfect vortex beams, whose energy is relatively concentrated and can capture particles. Simultaneously, based on a special light field intensity distribution design, it can effectively sort low-refractive-index particles of different sizes, offering advantages such as high flexibility and ease of operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a device for sorting low-refractive-index particles based on perfect vortex light.

[0025] Figure 2 This is a schematic diagram of low-refractive-index particle size sorting based on perfect vortex light, according to an embodiment of the present invention.

[0026] Figure 3 This is a data graph showing the photodynamic effects experienced by particles when they are captured by the light field and move to the sorting channel.

[0027] Figure 4 This image was captured during the feasibility verification of a method for sorting low-refractive-index particles based on perfect vortex light by the imaging module.

[0028] In the picture: 1. Laser emission assembly; 2. Beam modulation assembly; 3. Focusing assembly; 4. Illumination assembly; 5. Sample cell; 6. Imaging module; 7. Inner ring light field; 8. Outer ring light field; 9. Sorting channel. Detailed Implementation

[0029] The technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments, not all embodiments.

[0030] The method for sorting low-refractive-index particles based on perfect vortex light of the present invention includes a capture process and a sorting process.

[0031] Capture process: The laser is modulated by a spatial light modulator to form a double-ring perfect vortex light field in the sample cell. The double-ring perfect vortex light field has an inner ring light field and an outer ring light field. The gap between the inner ring light field and the outer ring light field is continuously reduced locally, thus forming a sorting channel. The double-ring perfect vortex light field is used to irradiate low refractive index particles, so that the particles are captured between the inner ring light field and the outer ring light field. Sorting process: Low-refractive-index particles move between the inner and outer ring light fields, driven by the phase gradient force generated by the orbital angular momentum of the light fields. When multiple captured particles move to the sorting channel, the direction of the optical repulsion force on the large-sized particles points towards the interior of the inner ring light field, thus driving them into the interior region of the inner ring light field, completing the sorting. At the same time, the optical force on the small-sized particles still meets the stable capture conditions, and they continue to move between the inner and outer ring light fields. Therefore, particles of different sizes are separated into different regions to complete the particle sorting process.

[0032] The double-ring perfect vortex light field is composed of multiple perfect vortex beams; the perfect vortex beams are three perfect vortex beams with different curves.

[0033] For the design of the light field, the light field consists of three parts: the outer ring light field is a perfect vortex light field I with a perfect circular ring curve, the left half of the inner ring light field is a perfect vortex light field II with a semi-circular ring curve, and the right half of the inner ring light field is a perfect vortex light field III with a semi-elliptical ring curve.

[0034] The perfectly curved vortex beam is generated by modulation using a spatial light modulator. The phase map loaded onto the spatial light modulator is first used to generate a double-ring perfect vortex light field using holographic shaping techniques, and then obtained through multiple iterations using the frequency-domain double-constraint Gerchberg-Saxton (F-DCGS) algorithm. A single perfectly curved vortex beam is represented on the focal plane as follows: ; in These are the coordinates of the focal plane. Let be the complex amplitude of the light field at the incident plane of the focusing lens, and its expression is: ; in Represents a curve and , ,parameter The upper limit of the angle of the integration path is used to control the integrity of the closed curve (when...). The curve generated at that time is a closed curve. The phase on the curve is determined, and its expression is: ; in This is a constant value that determines the phase gradient on the curve. It is a constant. The double-ring perfect vortex light field consists of three parts: outer ring curve I Left half of the inner ring II and the right half of the inner ring III The total light field is expressed as: ; in , and The different curved light fields generated by the above method were normalized before combination.

[0035] For the capture process, the laser beam is modulated into a double-ring perfect vortex optical field and focused into a sample cell containing a solution of low-refractive-index microparticles to be captured. Due to momentum exchange caused by the interaction between light and matter, the low-refractive-index microparticles are subjected to repulsive forces in the optical field. These forces are divided into intensity gradient forces caused by non-uniform light field intensity distribution and phase gradient forces caused by non-uniform phase distribution. Specifically, in this invention, the double-ring perfect vortex optical field in the focusing plane perpendicular to the light propagation direction provides a sufficient intensity distribution to capture the low-refractive-index microparticles. The particles are stably trapped between the two rings by the repulsive forces of both the outer and inner rings.

[0036] For the sorting process, each curved perfect vortex in the double-ring perfect vortex optical field has a certain topological charge, i.e., it has a non-uniform phase distribution. Therefore, multiple low-refractive-index particles trapped by the double rings move along the double-ring orbits of the double-ring perfect vortex optical field to the sorting channel under the drive of the phase gradient force. The sorting channel has a narrow orbit. Due to the spacing between the double rings… Changes occur, altering the intensity distribution of the light field and thus changing the photodynamic forces acting on particles within it. Due to their size, larger particles experience a net repulsive force at the sorting channel that points inward, causing them to derail and enter the inner region of the light field. Simultaneously, smaller particles remain stably captured at the sorting channel, allowing them to pass smoothly and continuously circulate in a double-ring orbit. Through a unique double-ring perfect vortex light field design, low-refractive-index particles of different sizes in the solution can be separated into different regions of the light field for stable and efficient sorting and capture.

[0037] like Figure 1 and 2 As shown, based on the same inventive concept, this embodiment of the invention also provides a device for sorting low-refractive-index particle sizes based on perfect vortex light, including a sample cell 5, a modulated light source module, an illumination component 4, and an imaging module 6.

[0038] Specifically, sample cell 5 is used to contain a solution of low-refractive-index particles to be captured. A modulated light source module is used to generate a double-ring perfect vortex light field to capture and sort the low-refractive-index particles in the sample cell. The double-ring perfect vortex light field has an inner ring light field 7 and an outer ring light field 8, with a locally decreasing spacing between the inner ring light field 7 and the outer ring light field 8, thereby forming a sorting channel 9.

[0039] Specifically, the low-refractive-index particles in the microparticle solution have a radius of 3-6 μm. The effective refractive index of the low-refractive-index particles is n=1.07, the refractive index of the surrounding medium is n=1.33, and the low-refractive-index particles in the microparticle solution are hollow glass spheres made of glass.

[0040] In this embodiment, the modulated light source module includes: a laser emission component 1, a beam modulation component 2, and a focusing component 3.

[0041] Specifically, the laser emission component 1 is used to generate a laser beam. The output optical power of the laser emission component is 30-5140mW, and the wavelength of the laser beam it generates is 1064nm.

[0042] Specifically, the beam modulation component 2 is used to modulate and shape the laser to form a double-ring perfect vortex light field.

[0043] Specifically, the beam modulation component 2 is used to modulate the laser beam generated by the laser emission component into a double-ring perfect vortex light field for capturing low refractive index particles, and to sort low refractive index particles of different sizes into different regions for separate capture.

[0044] In this embodiment, the focusing component 3 is used to focus the modulated and shaped light field onto the solution inside the sample cell 5.

[0045] In this embodiment, the illumination component 4 is a white LED, which is used to provide white light to the sample cell 5. The white light illuminates the sample cell after passing through the objective lens.

[0046] In this embodiment, the imaging module 6 is used to form an image of the manipulation process of the target particles.

[0047] The working method of this device for sorting low-refractive-index particle sizes based on perfect vortex light specifically includes the following steps: First, 0.15g of hollow glass sphere sample powder (effective refractive index n=1.07) was dispersed in 10ml of ultrapure water. The solution was then sonicated for 9 minutes to ensure uniform distribution of the hollow glass sphere particles in the liquid. The sonicated solution was filtered through filter paper (maximum pore size 6-8μm). Using a 1ml microsyringe, 0.5ml of the filtered sample was transferred to the concave groove of a single-sided concave glass slide. The droplet volume was controlled to precisely fill the groove area. The coverslip was slowly lowered along one side to avoid air bubbles, thus forming a sample cell. Finally, the sample cell was placed on the sample stage and secured with a slide clamp.

[0048] The laser generated by the laser emission component is modulated by the spatial light modulator. After passing through the focusing component 3, the laser beam is perpendicularly irradiated into the low refractive index particles to form a double-ring perfect vortex light field in the sample cell until the particles are stably captured by the double-ring perfect vortex light field. The double-ring perfect vortex light field is composed of multiple perfect vortex beams. The distance between the inner ring light field and the outer ring light field has a continuously decreasing part, which is the sorting channel.

[0049] Low-refractive-index particles in the double-ring perfect vortex light field move in double-ring orbits driven by phase gradient forces. Subsequently, when the low-refractive-index particles move to the narrow sorting channel, the large-sized particles are subjected to inward optical forces and enter the inner ring light field 7, while the small-sized particles that meet the stable capture conditions continue to move between the inner ring light field 7 and the outer ring light field 8.

[0050] Figure 2 This is a schematic diagram of a method for sorting low-refractive-index particles based on perfect vortex light according to an embodiment of the present invention. When low-refractive-index particles move into the sorting channel, due to the difference in the light force they receive, larger particles are derailed into the light field by an inward light force, while smaller particles still meet the capture conditions and continue to move in the double-ring perfect vortex light field under the drive of the phase gradient force.

[0051] Figure 3 This is a schematic diagram illustrating the principle of a method for sorting low-refractive-index particles based on perfect vortex light according to an embodiment of the present invention. A beam modulation component modulates a laser beam into a double-ring perfect vortex light field composed of multiple curved perfect vortex beams. After being focused by a focusing component, the laser beam illuminates the low-refractive-index particles in the sample cell. When the particles are captured by the light field and move to the sorting channel, they experience the following optical force: Figure 3 As shown. Figure 3 Different colored solid lines represent different The photodynamic force experienced by a 4.0 μm particle in a double-ring perfect vortex light field with a minimum ring spacing (value of minimum ring spacing). Due to the photorepulsive force, low-refractive-index particles tend to move inwards within the light field in a light field with a sufficiently small minimum ring spacing. However, large particles in the light field do not meet the trapping condition (potential well depth greater than a certain value). , It is Boltzmann's constant. When the temperature is reached, it derails and enters the inner region of the light field.

[0052] The feasibility of the low-refractive-index particle size sorting method based on perfect vortex light is verified using imaging module 6 below: After the microparticle solution is prepared, the output power of the laser emission component 1 is slowly adjusted to about 3100mW; the dispersion of the hollow glass sphere microparticles and the focusing of the light spot are observed through the image formed by the imaging module 6; the laser beam emitted by the laser emission component 1 is modulated by the beam modulation component 2 and then focused by the focusing component 3 into the sample cell 6 to form a double-ring perfect vortex light field.

[0053] like Figure 4 As shown, the red dashed line represents the reference position of the double-ring perfect vortex light field in the sample cell, the white arrow in the lower left corner indicates the direction of particle motion on the double-ring track, and the upper right corner shows the corresponding time in the video. The minimum spacing of the double-ring perfect vortex light field used is also shown. The radii are 3.3 μm. At t=0 s, four hollow glass sphere particles are stably trapped between the inner and outer ring optical fields of the double-ring perfect vortex optical field, with radii decreasing from 4.7 μm, 4.2 μm, 3.6 μm, and 3.3 μm, respectively. As time progresses, under the influence of the phase gradient force of the optical field, the largest particle moves to the sorting channel and is repelled by the optical field, entering the inner region of the optical field. The remaining three smaller particles continue to move on the double-ring orbit after passing through the narrow region of the double ring. This method achieves size sorting by separating low-refractive-index particles of different sizes into different regions of the optical field, and this sorting process achieves a resolution of 0.5 μm radius difference.

[0054] Although embodiments of this application have been shown and described above, the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be conceived without inventive effort should be covered within the scope of protection of this invention. Unless expressly stated otherwise, no element, action or instruction used herein should be construed as critical or necessary.

Claims

1. A method for sorting low-refractive-index particles based on perfect vortex light, characterized in that, Includes the following steps: The solution containing low-refractive-index microparticles is placed in the sample cell; Multiple perfect vortex beams are focused at the sample cell to form a double-ring perfect vortex light field to irradiate low refractive index particles. The dual-ring perfect vortex optical field has an inner ring optical field and an outer ring optical field, and the spacing between the inner ring optical field and the outer ring optical field is continuously reduced at least locally to form a sorting channel; The low-refractive-index particles in the double-ring perfect vortex light field move between the inner ring light field and the outer ring light field under the driving force of the phase gradient force. When the low-refractive-index particles move to the sorting channel, the larger low-refractive-index particles are subjected to inward optical force and enter the interior of the inner ring optical field, while the smaller low-refractive-index particles continue to move between the inner ring optical field and the outer ring optical field after passing through the sorting channel.

2. The method for sorting low-refractive-index particles based on perfect vortex light according to claim 1, characterized in that, The outer ring light field is a perfect vortex light field with a circular annular curve shape; The left half of the inner ring light field is a perfect vortex light field in the shape of a semi-circular ring curve, and the right half of the inner ring light field is a perfect vortex light field in the shape of a semi-elliptical ring curve.

3. The method for sorting low-refractive-index particles based on perfect vortex light according to claim 2, characterized in that, The low-refractive-index microparticles are hollow glass spheres.

4. The method for sorting low-refractive-index particles based on perfect vortex light according to claim 3, characterized in that, The low-refractive-index microparticles have a radius of 3-6 μm.

5. A low-refractive-index particle size sorting device based on perfect vortex light, characterized in that, include: The sample cell is used to contain a solution of low-refractive-index particles to be sorted. as well as A modulated light source module is used to generate a double-ring perfect vortex light field to sort low-refractive-index particles in a sample cell; The double-ring perfect vortex optical field has an inner ring optical field and an outer ring optical field, and the spacing between the inner ring optical field and the outer ring optical field is continuously reduced at least locally to form a sorting channel. Among them, the low refractive index particles in the double-ring perfect vortex light field move between the inner ring light field and the outer ring light field under the driving force of the phase gradient force; When the low-refractive-index particles move to the sorting channel, the larger low-refractive-index particles are subjected to inward optical force and enter the interior of the inner ring optical field, while the smaller low-refractive-index particles continue to move between the inner ring optical field and the outer ring optical field after passing through the sorting channel.

6. The low-refractive-index particle size sorting device based on perfect vortex light according to claim 5, characterized in that, The modulated light source module includes: Laser emission assembly, used to generate a laser beam; Beam modulation assembly for modulating and shaping the laser beam; and A focusing component is used to focus the laser emitted from the beam modulation component to form the double-ring perfect vortex light field in the sample cell.

7. The low-refractive-index particle size sorting device based on perfect vortex light according to claim 5, characterized in that, Also includes: An imaging module is used to capture images of the process of sorting the low-refractive-index particles.

8. The low-refractive-index particle size sorting device based on perfect vortex light according to claim 6, characterized in that, The wavelength of the laser beam is 1064 nm.

9. A low-refractive-index particle size sorting device based on perfect vortex light according to claim 5, characterized in that, Also includes: An illumination assembly for providing white light to illuminate the sample cell.

Images