A spatio-temporal hybrid multi-mode vortex optical particle manipulation system and method

Abstract

The present invention discloses a spatio-temporal hybrid multi-mode vortex optical particle manipulation system and method, which relates to the application field of laser optical manipulation technology. This system includes a laser light source (1), a vortex light generation module (2), a dichroic mirror (3), a first objective lens (4), a stage (5), an illumination lamp (6), an XYZ three-axis displacement control module (7), a first camera (8), a particle display and trajectory planning module (9), a second objective lens (10), and a second camera (11). The present invention has the following advantages and positive effects: 1. The spatio-temporal hybrid vortex optical manipulation system modulates the vortex light in combination with two dimensions of time and space to further manipulate particles; 2. The automated particle trajectory planning optimizes the particle manipulation process and the system operation mode; and 3. It can be applied in many fields such as biomedicine, atomic physics, chemistry, and micro-mechanics to achieve more flexible particle manipulation.

Description

Technical Field

[0001] The present invention relates to the application field of laser optical manipulation technology, and particularly to a spatio-temporal hybrid multi-mode vortex light particle manipulation system and method thereof. Background Art

[0002] Optical manipulation technology refers to that based on the principle of conservation of momentum, when light interacts with microparticles during propagation, the momentum of the light beam itself is converted into the force acting on the microparticles, so as to realize the manipulation of microparticles such as capture, push-pull and rotation. Since optical manipulation technology can perform non-contact, non-destructive and high-precision manipulation on microparticles, in recent years, optical manipulation technology has been widely applied and developed in the fields of biology, atomic physics, etc. The above-mentioned optical momentum includes linear momentum and angular momentum. Early optical manipulation technology mainly used the linear momentum contained in all light beams for manipulation, and the angular momentum was mainly achieved by applying polarization states to the light beams. With the gradual in-depth research on vortex beams with orbital angular momentum, their characteristics of having a vortex light intensity distribution, vector polarization state and rich orbital angular momentum have been widely applied and developed in the field of optical manipulation, especially the manipulation of high refractive index particles such as metals and low refractive index biological particles can be realized simultaneously.

[0003] At present, certain achievements have been made in the research of vortex light manipulation technology. The invention patent with the publication number of CN109188673A proposes an adjustable optical tweezer device. The optical path structure of this device is simple, and the optical tweezer operation is continuously adjustable. However, this system can only adjust the position of the phase singularity of the vortex light, but the regulation of the vortex light mode is very simple. The invention patent with the publication number of CN109116539A proposes an optical tweezer real-time moving control system. This system uses a three-dimensional position data acquisition structure and can realize dynamic movement in the XY plane and Z plane. However, its three-dimensional movement is sequential movement, and it cannot move simultaneously in three axes and each step is set manually, so the manipulation process is complex. The invention patent with the publication number of CN113223744A proposes an optical micro-manipulation device and method for ultrafast regulation of vector vortex light field, and realizes particle manipulation of ultrafast optical tweezers based on femtosecond laser. Generally speaking, the existing particle manipulation systems based on vortex light mostly rely on a single mode, a single trajectory, or have the problem of low automation, and it is difficult to be widely applied in actual biomedical and atomic measurement.

[0004] To further apply optical manipulation technology to industrial applications, more integrated and optimized optical manipulation systems and methods are still needed. In view of the above problems, the present invention constructs a spatio-temporal hybrid multi-mode vortex light particle manipulation system and method thereof. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects and deficiencies existing in the prior art, and provide a spatio-temporal hybrid multi-mode vortex light particle manipulation system and method thereof, so as to realize automated manipulation applications such as particle capture, rotation, push-pull, etc.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] 1. A spatio-temporal hybrid multi-mode vortex optical particle manipulation system (hereinafter referred to as the system)

[0008] This system includes a laser light source, a vortex light generation module, a dichroic mirror, a first objective lens, a stage, a lighting lamp, an XYZ three-axis displacement control module, a first camera, a particle display and trajectory planning module, a second objective lens, and a second camera;

[0009] The laser light source, the vortex light generation module, and the dichroic mirror interact in sequence to generate and transmit a vortex beam with a certain mode and polarization state;

[0010] Then, the dichroic mirror interacts with the first objective lens and the first camera respectively;

[0011] On one side, the dichroic mirror, the first objective lens, the stage, and the lighting lamp interact in sequence; meanwhile, the XYZ three-axis displacement control module is connected to the stage, and together with the optical path, it realizes the manipulation of the particles in the sample cell on the stage;

[0012] On the other side, the dichroic mirror, the first camera, and the particle display and trajectory planning module interact in sequence; meanwhile, the stage, the second objective lens, the second camera, and the connected particle display and trajectory planning module interact in sequence; the two sets of routes together realize the three-dimensional display of the particle manipulation process and the trajectory planning process;

[0013] The particle display and trajectory planning module interacts with the laser light source and the vortex light generation module respectively, feeds back the trajectory planning result, and further manipulates the particles.

[0014] 2. A spatio-temporal hybrid multi-mode vortex optical particle manipulation method

[0015] This method includes the following steps:

[0016] ① According to the three-dimensional results displayed by the first camera and the second camera, and according to the set particle manipulation requirements, calculate and plan the required light source wavelength, power, and the polarization state and mode of the vortex light;

[0017] ② According to the calculation results, adjust the laser light source in real time to generate a laser with the corresponding power and wavelength, and adjust the vortex light generation module to make the output laser generate a vortex light with the required polarization state and mode;

[0018] ③ The vortex light irradiates the particles through the dichroic mirror and the first objective lens with a high numerical aperture in sequence to achieve real-time dynamic particle manipulation;

[0019] ④The particles are illuminated by the illuminating lamp and sequentially pass through the first objective lens and the dichroic mirror, and are imaged on the XY plane by the first camera; at the same time, they sequentially pass through the second objective lens and the second camera and are imaged on the XZ plane; this further assists in the generation of vortex light and the manipulation of particles in the next stage.

[0020] ⑤Repeat the above steps until the particles reach the specified position.

[0021] The present invention has the following advantages and positive effects:

[0022] 1. The space-time hybrid vortex light manipulation system modulates the vortex light in combination with two dimensions of time and space to further manipulate the particles; in terms of time sequence, different state vortex lights are used to achieve real-time dynamic particle manipulation, and in terms of space, multiple modes of vortex light are multiplexed to manipulate different particles simultaneously.

[0023] 2. The automated particle trajectory planning optimizes the particle manipulation process and the system operation mode; according to the manipulation requirements such as particle screening and transportation, the system is optimized and regulated, and a particle manipulation system with higher integration and automation is realized.

[0024] 3. In addition to the three-dimensional manipulation, the vortex light particle manipulation system further adds a rotation dimension, and theoretically can achieve arbitrary particle manipulation at the microscopic level, and can be applied in many fields such as biomedicine, atomic physics, chemistry, and micro machinery, realizing more flexible particle manipulation. Description of the Drawings

[0025] Figure 1 is the structural diagram of the present system, in the figure:

[0026] 1 - Laser light source,

[0027] 2 - Vortex light generation module,

[0028] 3 - Dichroic mirror,

[0029] 4 - Objective lens,

[0030] 5 - Stage,

[0031] 6 - Illuminating lamp,

[0032] 7 - XYZ three-axis displacement control module,

[0033] 8 - Camera,

[0034] 9 - Particle display and trajectory planning module.

[0035] Figure 2 is the step diagram of the present method. Detailed Embodiment

[0036] To make the technical solutions and advantages of the present invention more clear, the following will be described in detail with reference to the drawings and embodiments:

[0037] I. System

[0038] 1. Overall

[0039] As shown in Figure 1 , this system includes a laser light source 1, a vortex light generation module 2, a dichroic mirror 3, a first objective lens 4, a stage 5, an illumination lamp 6, an XYZ three-axis displacement control module 7, a first camera 8, a particle display and trajectory planning module 9, a second objective lens 10, and a second camera 11;

[0040] The laser light source 1, the vortex light generation module 2, and the dichroic mirror 3 interact in sequence to generate and transmit a vortex beam with a certain mode and polarization state;

[0041] Then, the dichroic mirror 3 interacts with the first objective lens 4 and the first camera 8 respectively;

[0042] On one side, the dichroic mirror 3, the first objective lens 4, the stage 5, and the illumination lamp 6 interact in sequence; meanwhile, the XYZ three-axis displacement control module is connected to the stage and jointly with the optical path realizes the manipulation of the particles in the sample cell on the stage 5;

[0043] On the other side, the dichroic mirror 3, the first camera 8, and the particle display and trajectory planning module 9 interact in sequence; meanwhile, the stage 5, the second objective lens 10, the second camera 11, and the connected particle display and trajectory planning module 9 interact in sequence; the two groups of routes jointly realize the three-dimensional display of the particle manipulation process and the trajectory planning process;

[0044] The particle display and trajectory planning module 9 interacts with the laser light source 1 and the vortex light generation module 2 respectively, feeds back the trajectory planning result, and further manipulates the particles.

[0045] 2. Functional components

[0046] 1) The laser light source 1 is a laser source with an appropriate power and tunable wavelength, usually in the range of 400 - 2000 nm, and the power depends on the size of the particles to be manipulated. Generally, the size of the particles manipulated by this system is in the range of nm to dozens of um;

[0047] 2) The vortex light generation module 2 is a common beam modulation optical path, and its main function is to expand, collimate, load polarization, and modulate the beam emitted by the laser light source 1 into a vortex beam with a specific mode, where:

[0048] ① The beam expansion and collimation are realized by using common convex and concave lenses on the laser output optical path;

[0049] ② The generation of the vortex beam uses a computer-generated hologram or a liquid crystal spatial light modulator to modulate the phase and amplitude of the vortex light;

[0050] ③Vortex light mode multiplexing mainly uses the orbital angular momentum formed by positive and negative helical directions or multiple models to stably clamp particles or screen various types of particles;

[0051] ④Vector beams with any polarization state can be achieved by controlling the phase difference between two circularly polarized lights. In this embodiment, the computer with trajectory planning controls two spatial light modulators to generate vortex beams with any polarization state.

[0052] ⑤In addition to ordinary linear polarization and circular polarization, radial and azimuthal polarization are unique to vortex light. According to the need to manipulate particles, radially polarized vortex light is mainly used to capture high refractive index particles, and azimuthally polarized vortex light is mainly used to manipulate low refractive index particles.

[0053] 3) The first objective lens 4 and the second objective lens 10 are special functional components. Usually, high numerical aperture objective lenses are selected, and the focal length can be dynamically adjusted. Its function is to focus the light beam into the sample cell for particle manipulation.

[0054] 4) The stage 5 is a common functional component. A sample cell containing particles is placed on it and is controlled by the XYZ three-axis displacement control module 7 to perform three-axis synchronous displacement operations.

[0055] 5) The illuminating lamp 6 is a common functional component. It always remains perpendicular to the stage 5 so that it always vertically and stably irradiates the particles in the sample cell.

[0056] 6) The XYZ three-axis displacement control module 7 is a commonly used functional component. Its main characteristics are small displacement step size and small total displacement range, and it is used to perform three-axis displacement operations on the stage.

[0057] 7) The first camera 8 and the second camera 11 are special functional components. Different from ordinary cameras, here they are high-speed and high-resolution cameras of CCD or CMOS, and the minimum resolution reaches the nm level.

[0058] 8) The particle display and trajectory planning module 9 is a special functional component, which consists of a computer display module and a trajectory planning algorithm. Its function is to display the particle image, calculate the trajectory required for particle manipulation, and feedback the required light source parameters and vortex light parameters.

[0059] II. Method

[0060] As Figure 2 , this method includes the following steps:

[0061] S1. According to the set particle manipulation requirements, calculate and plan the required light source wavelength, power, vortex light polarization state, and mode;

[0062] S2. According to the calculation results, the laser light source is adjusted in real time to generate laser light with corresponding power and wavelength, and the vortex light generation module is adjusted to make the output laser generate vortex light with the required polarization state and mode;

[0063] S3. The vortex light irradiates the particles through a dichroic mirror and a high numerical aperture first objective lens in sequence to achieve real-time dynamic particle manipulation;

[0064] S4. The particles are illuminated by an illumination lamp and imaged on the XY plane by the first camera through the first objective lens and the dichroic mirror in sequence; at the same time, they are imaged on the XZ plane by the second objective lens and the second camera in sequence; further assisting the generation of vortex light and particle manipulation in the next stage.

[0065] S5. Repeat the above steps until the particles reach the specified position.

[0066] The trajectory planning features are as follows: in terms of time - dynamically adjusting the number of vortex light modes, the vortex direction and the light polarization state in sequence; in terms of space - superimposing vortex light beams of multiple modes to achieve the capture, rotation, push and pull of particles; among them, the trajectory planning principle is as follows:

[0067] A. The spiral phase structure of the vortex light is m is the topological charge number, is the azimuth angle;

[0068] B. The numerical value of the topological charge number m of the vortex light determines the rotation radius of the particles and is related to the rotation speed of the particles;

[0069] C. The sign of the topological charge number m of the vortex light determines the rotation direction of the particles and is related to the axial movement direction of the particles;

[0070] D. The trajectory planning is mainly based on the torque required to transport the particles to the specified position, and then calculates the required mode and polarization state of the vortex light.

[0071] III. Embodiment

[0072] This embodiment includes the following processes:

[0073] ① Initial capture

[0074] A. The laser outputs initially. The tunable laser light source 1 emits an initial Gaussian beam with a wavelength of 450 nm; [[ID=4…]]

[0075] B. Vortex light regulation

[0076] a. The vortex light generation module first expands the beam emitted by the laser using a concave lens, and then collimates the beam using a convex lens to obtain a parallel beam;

[0077] b. The collimated beam enters the liquid crystal spatial light modulator, modulating the Gaussian beam into a vortex beam with a certain amplitude and phase structure; among them, the topological charge number of the vortex beam is modulated to m = 10;

[0078] c. Polarization is loaded. Since a vector beam with any polarization state can be achieved by controlling the phase difference between two circularly polarized beams, in this embodiment, a computer for trajectory planning controls two spatial light modulators to generate a vortex beam with any polarization state.

[0079] C. Capturing particles

[0080] The generated vortex light passes through a microscope objective lens with a numerical aperture of 0.9, focusing the beam inside the sample cell; combined with an axial and a lateral high-speed CCD camera, the particles to be manipulated are captured inside the vortex beam, making them stable at the center inside the beam.

[0081] ② Particle transportation

[0082] A. Trajectory planning

[0083] According to the position where the particle finally needs to be transported as set, as well as the particle size and position obtained by the camera collecting images, the particle display and trajectory planning module performs planning calculations on the manipulation trajectory to obtain the required light source wavelength and power, vortex light mode and polarization state;

[0084] Trajectory planning mainly calculates the mode and polarization state of the vortex light based on the torque required to transport the particle to the specified position; among them, the numerical value of the vortex light mode m determines the rotation radius of the particle and is related to the rotation speed of the particle; the sign of m determines the rotation direction of the particle.

[0085] B. Re-regulation of the light source and vortex light

[0086] a. The particle display and trajectory planning module transmits the planning results to the laser light source and the vortex light generation module, modulating the laser to generate a light source with the corresponding wavelength and power, and modulating the vortex light generation module to generate a vortex light with the corresponding mode and polarization state;

[0087] b. The modulated vortex light is tightly focused on the particle again through a high numerical aperture objective lens, bringing new momentum to the particle and making the particle perform a three-dimensional vortex motion;

[0088] c. Repeat the above operations until the particle is transported to the required position.

[0089] Finally, it should be noted that the above embodiments are specifically implemented on the premise of the technical solution of the present invention, giving detailed implementation manners and operation processes, but the protection scope of the present invention includes but is not limited to the above embodiments.

Claims

1. A spatio-temporal hybrid multi-mode vortex optical particle manipulation system, characterized in that: It includes a laser light source (1), a vortex light generation module (2), a dichroic mirror (3), a first objective lens (4), a stage (5), an illumination lamp (6), an XYZ three-axis displacement control module (7), a first camera (8), a particle display and trajectory planning module (9), a second objective lens (10), and a second camera (11); The laser light source (1), the vortex light generation module (2), and the dichroic mirror (3) interact in sequence to generate and transmit a vortex light beam with a certain mode and polarization state; Then the dichroic mirror (3) interacts with the first objective lens (4) and the first camera (8) respectively; On one side, the dichroic mirror (3), the first objective lens (4), the stage (5), and the illumination lamp (6) interact in sequence; at the same time, the XYZ three-axis displacement control module (7) is connected to the stage (5) to jointly realize the manipulation of particles in the sample cell on the stage (5) with the optical path; On the other side, the dichroic mirror (3), the first camera (8), and the particle display and trajectory planning module (9) interact in sequence; at the same time, the stage (5), the second objective lens (10), the second camera (11), and the connected particle display and trajectory planning module (9) interact in sequence; the two sets of routes jointly realize the three-dimensional display of the particle manipulation process and the trajectory planning process; The particle display and trajectory planning module (9) interacts with the laser light source (1) and the vortex light generation module (2) respectively, feeds back the trajectory planning result, and further manipulates the particles; Its manipulation method is: ① According to the three-dimensional results displayed by the first camera and the second camera, calculate and plan the required light source wavelength, power, vortex light polarization state, and mode according to the set particle manipulation requirements; ② According to the calculation results, adjust the laser light source in real time to generate a laser with the corresponding power and wavelength, and adjust the vortex light generation module to make the output laser generate a vortex light with the required polarization state and mode; ③ The vortex light irradiates the particles successively through the dichroic mirror and the first objective lens with a high numerical aperture to achieve real-time dynamic particle manipulation; ④ The particles are illuminated by the illumination lamp and imaged on the XY plane by the first camera successively through the first objective lens and the dichroic mirror; at the same time, they are imaged on the XZ plane by the second camera successively through the second objective lens; further assisting the generation of vortex light and particle manipulation in the next stage; ⑤ Repeat the above steps until the particles reach the specified position; The trajectory planning features are: temporally - dynamically adjusting the number of vortex light modes, vortex direction, and light polarization state in sequence; spatially - superimposing vortex light beams of multiple modes to achieve the capture, rotation, push, and pull of particles; among them, the trajectory planning principle is as follows: A. The helical phase structure of the vortex light is where m is the topological charge number, and is the azimuth angle; B. The numerical value of the topological charge number m of the vortex light determines the rotation radius of the particle and is related to the rotation speed of the particle; C. The sign of the topological charge number m of the vortex light determines the rotation direction of the particle and is related to the axial movement direction of the particle; D. The trajectory planning is mainly based on the torque required to transport the particles to the specified position, and then calculates the required mode and polarization state of the vortex light.

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