Phase control method, device and system for holographic optical tweezers potential well stiffness

Abstract

The application discloses a holographic optical tweezers potential well stiffness phase control method, device and system, the method comprises the following steps: calculating the decomposition matrix formula, matrix expression and Hermite matrix expression according to the input system configuration parameters, expanding the stiffness coefficient of the optical trap through the Hermite matrix expression to obtain the stiffness coefficient expansion expression, optimizing the phase of the spatial light modulator based on the pixel symmetry rule to obtain the optimized phase value, generating the control instruction through the optimized phase value and sending it to the spatial light modulator, and recalculating the coefficient value of the stiffness coefficient expansion expression, if the coefficient value or the optimization times meet the iterative optimization condition, return to execute the phase optimization step of the spatial light modulator. The above-mentioned phase control method can solve the Hermite matrix expression and the stiffness coefficient expansion expression according to the system configuration parameters, generate the control instruction to modulate the phase of the light beam, and improve the application effect of the phase of the potential well stiffness through phase iterative optimization.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spatial light modulation, and in particular to a holographic optical tweezers potential well stiffness phase control method, device and system. BACKGROUND

[0002] The existing optical tweezers generally use a diffraction-limited ordinary Gaussian light beam to capture the sample. For a uniform spherical sample, when the sample radius is greater than the wavelength of the laser, the potential well stiffness of the ordinary optical tweezers decreases with the increase of the sample radius, and is approximately inversely proportional to the change. Therefore, for a large-diameter sample, the potential well stiffness of the ordinary optical tweezers is small, and the capture is unstable. In order to improve the stability of the light beam in capturing the sample, the potential well stiffness can be optimized. The existing technical method generally needs to optimize and modulate the phase and light intensity at the same time, and the implementation process is very complex. If the phase of the potential well stiffness is optimized alone according to the existing technology, there is a problem of poor optimization effect. Therefore, the method for optimizing the potential well stiffness of the optical tweezers in the existing technical method has the problem of high optimization complexity. SUMMARY

[0003] The embodiments of the present application provide a holographic optical tweezers potential well stiffness phase control method, device and system, which aims to solve the problem of high optimization complexity of the method for optimizing the potential well stiffness of the optical tweezers in the existing technical method.

[0004] In a first aspect, the embodiments of the present application provide a holographic optical tweezers potential well stiffness phase control method, which is applied to a controller, and the controller is in communication connection with a spatial light modulator in a phase control system, wherein the method comprises:

[0005] If the input system configuration parameters are received, the plane wave decomposition is performed on the electric field of the optical trap according to the system configuration parameters, so as to obtain a corresponding decomposition matrix formula;

[0006] The decomposition matrix formula is transformed according to the preset vector spherical harmonic function and the light beam distribution of the spatial light modulator, so as to obtain a corresponding matrix expression;

[0007] The Hermite matrix expression corresponding to the matrix expression is calculated according to the light beam distribution of the spatial light modulator;

[0008] The stiffness coefficient of the optical trap is unfolded according to the Hermite matrix expression, so as to obtain a corresponding stiffness coefficient unfolding expression;

[0009] The phase of the spatial light modulator is optimized according to the pixel symmetry rule, the Hermite matrix expression and the preset phase limitation condition, so as to obtain an optimized phase value;

[0010] generating a corresponding control instruction according to the optimized phase value and sending the control instruction to the spatial light modulator to perform phase control on the spatial light modulator;

[0011] recalculating coefficient values ​​of the stiffness coefficient expansion expression according to the beam distribution of the spatial light modulator after phase control;

[0012] If the coefficient value or the number of optimizations satisfies a preset iterative optimization condition, the process returns to the step of performing phase optimization on the spatial light modulator to perform iterative phase optimization on the spatial light modulator.

[0013] In a second aspect, an embodiment of the present invention further provides a phase control device for the potential well stiffness of a holographic optical tweezers, wherein the device is configured in a controller, and the controller is communicatively connected to a spatial light modulator in a phase control system, wherein the device is used to perform the phase control method for the potential well stiffness of a holographic optical tweezers as described in the first aspect above, and the device includes:

[0014] a decomposition unit configured to, upon receiving input system configuration parameters, perform plane wave decomposition on the electric field of the light trap according to the system configuration parameters to obtain a corresponding decomposition matrix;

[0015] a transformation unit, configured to transform the decomposed matrix expression according to a preset vector spherical harmonic function and the beam distribution of the spatial light modulator to obtain a corresponding matrix expression;

[0016] a calculation unit, configured to calculate a Hermitian matrix expression corresponding to the matrix expression according to the beam distribution of the spatial light modulator;

[0017] an expansion unit, configured to expand the stiffness coefficient of the light trap according to the Hermitian matrix expression to obtain a corresponding stiffness coefficient expansion expression;

[0018] A phase optimization unit, configured to perform phase optimization on the spatial light modulator according to a pixel symmetry rule, the Hermitian matrix expression, and a preset phase constraint condition to obtain an optimized phase value;

[0019] a control instruction sending unit, configured to generate a corresponding control instruction according to the optimized phase value and send the control instruction to the spatial light modulator to perform phase control on the spatial light modulator;

[0020] a coefficient value calculation unit, configured to recalculate the coefficient values ​​of the stiffness coefficient expansion expression according to the beam distribution of the spatial light modulator after phase control;

[0021] The return execution unit is configured to return to performing the phase optimization on the spatial light modulator to perform iterative phase optimization on the spatial light modulator if the coefficient value or the number of optimizations satisfies preset iterative optimization conditions.

[0022] In a third aspect, the embodiments of the present application further provide a holographic optical tweezers potential well stiffness phase control system, wherein the system comprises a controller, a laser, a beam expander, a half-wave plate, a polarization fractional cubic mirror, a spatial light modulator, an objective lens and a camera.

[0023] The laser is configured to emit a laser beam, the beam expander is arranged downstream of the laser, and the polarization fractional cubic mirror is arranged downstream of the beam expander.

[0024] The spatial light modulator is arranged downstream of the polarization fractional cubic mirror, a dichroic mirror is arranged downstream of the spatial light modulator, and the objective lens and the camera are arranged on two sides of the dichroic mirror, respectively.

[0025] The controller is communicatively connected to the spatial light modulator, and the controller comprises a processor, a communication interface, a memory and a communication bus.

[0026] The memory is configured to store a computer program.

[0027] When the processor executes the computer program stored in the memory, the steps of the holographic optical tweezers potential well stiffness phase control method according to the first aspect are implemented.

[0028] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the steps of the holographic optical tweezers potential well stiffness phase control method according to the first aspect.

[0029] The embodiment of the present application provides a holographic optical tweezers potential well stiffness phase control method, device and system, the method comprises the following steps: calculating a decomposition matrix formula, a matrix expression and an Hermite matrix expression according to input system configuration parameters, expanding the stiffness coefficient of the optical trap through the Hermite matrix expression to obtain a stiffness coefficient expansion expression, optimizing the phase of the spatial light modulator based on the pixel symmetry rule to obtain an optimized phase value, generating a control instruction through the optimized phase value and sending the control instruction to the spatial light modulator, and recalculating the coefficient value of the stiffness coefficient expansion expression, if the coefficient value or the optimization times meet the iterative optimization condition, the step of optimizing the phase of the spatial light modulator is returned to be executed. The phase control method of the optical tweezers potential well stiffness can solve the Hermite matrix expression and the stiffness coefficient expansion expression according to the system configuration parameters, modulate the phase of the light beam by generating the control instruction, maximize the coefficient value of the stiffness coefficient through phase iterative optimization, and improve the application effect of the phase of the potential well stiffness. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The method flow chart of the holographic optical tweezers potential well stiffness phase control method provided by the embodiment of the present application is provided.

[0032] Figure 2 The structure diagram of the holographic optical tweezers potential well stiffness phase control system provided by the embodiment of the present application is provided.

[0033] Figure 3 The schematic block diagram of the holographic optical tweezers potential well stiffness phase control device provided by the embodiment of the present application is provided.

[0034] Figure 4 The schematic block diagram of the computer device provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0036] It should be understood that the terms "comprises" and "comprising," when used in this specification and the following claims, indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0037] It should also be understood that the terms used in the specification of the application are only for the purpose of describing particular embodiments and are not intended to limit the application. As used in the specification and the appended claims of the application, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0038] It should be further understood that the term "and / or" used in the specification of the application and the appended claims means any combination of one or more of the associated listed items and all possible combinations thereof.

[0039] Please refer to Figure 1 As shown, the embodiment of the present application provides a phase control method for holographic optical tweezers potential well stiffness, which is applied to a controller. The method is executed by an application program installed in the controller. The controller can be a notebook computer, a desktop computer, a tablet computer, a mobile phone or other devices. The controller can also be a control panel for realizing data processing and instruction generation, such as a PLC (Programmable Logic Controller) circuit board with an MCU chip. As shown in the figure, Figure 2 The controller is in communication connection with a spatial light modulator in the phase control system. The controller can obtain system configuration parameters input by a user and light beam distribution of the spatial light modulator. The controller can also send corresponding control instructions to the spatial light modulator to control the phase of the spatial light modulator. As shown in the figure, Figure 1 The method includes steps S110-S180.

[0040] S110, if the input system configuration parameters are received, the electric field of the optical trap is decomposed into plane waves according to the system configuration parameters to obtain a corresponding decomposition matrix form.

[0041] If the input system configuration parameters are received, the electric field of the optical trap is decomposed into plane waves according to the system configuration parameters to obtain a corresponding decomposition matrix form. The system configuration parameters include imaging resolution, focal length, pixel size, imaging resolution, which is the resolution of the image obtained by the camera, can be used to reflect the degree of imaging accuracy. The higher the imaging resolution, the more accurate the image. The focal length is the focal length of the objective lens, and the unit of the focal length is mm (millimeter). The pixel size is the size of the pixel in the spatial light modulator.

[0042] Wherein, the phase control system of the holographic optical tweezers potential well stiffness is to modulate the phase of the light beam through the spatial light modulator, and to form a tightly focused light beam as the optical trap by using a high numerical aperture objective lens, so as to realize the capture of the sample. Wherein, the stiffness coefficient K of the optical trap can be expressed by the matrix quadratic form as formula (1);

[0043]

[0044] Wherein, wherein A is a set of basis of the electric field vector of the optical trap, that is A is the Hermite matrix for describing the interaction between the electric field and the substance, and A j is the jth vector in A, is the transposed matrix of the vector A. In order to specifically calculate K, the matrix and the vector A need to be expressed in a set of bases; for the implementation mode of the above method, the plane wave is selected as the base, and the calculation result can be conveniently applied. Since is the Hermite matrix, κ≤λ max |A| 2 , wherein λ max is the largest eigenvalue of the matrix , and the equality holds only when A is the corresponding eigenvector of λ max . However, in general, the Gaussian light cannot be modulated into the electric field expressed by the corresponding eigenvector through pure phase modulation, so the present application introduces iterative calculation to iteratively optimize the phase. In view of the characteristics of the spatial light modulator that each pixel is independently controlled, the present application also designs a set of iterative methods with fast convergence, and combines the pixel symmetry rule in the iterative process according to the actual application requirements.

[0045] In specific embodiments, step S110 includes the sub-steps of: determining the center coordinates of each pixel point in the spatial light modulator according to the imaging resolution and the pixel size in the system configuration parameters; determining the basis of plane wave decomposition according to the focal length in the system configuration parameters and the center coordinates; and performing plane wave decomposition on the electric field vector of the optical trap according to the basis of plane wave decomposition to obtain the corresponding decomposition matrix formula.

[0046] Specifically, the imaging resolution in the system configuration parameters is 2Mx2N, and the pixel size is s, so the center coordinates (x m ,y n ) of each pixel point are expressed by formula (2):

[0047]

[0048] According to the focal length in the system parameters and the center coordinates of the pixel points, the relationship between the coordinates (x, y) on the spatial light modulator and the focal length can be determined as shown in equation (3).

[0049]

[0050] where f is the focal length, k is the wave number, k = (2π) / λ, λ is the wavelength, and π is the circular constant. Since the spatial light modulator plane is equivalent to the back focal plane of the objective lens imaging, the plane wave decomposition can be selected to conveniently map the phase of A j to the phase of the corresponding pixel point on the spatial light modulator. For a single-frequency laser, the expression of the basis of the plane wave decomposition can be further determined as shown in equation (4):

[0051]

[0052] where k x , k y , and k z are the wave numbers corresponding to the three-dimensional coordinate values of the pixel point on the spatial light modulator in the x direction, y direction, and z direction, respectively, and the relationship between k x , k y , and k z satisfies For the laser propagating along the z direction, it satisfies e is the natural logarithm base, is the unit vector, and i is the imaginary part in the complex number.

[0053] Based on the above basis of the plane wave decomposition, the electric field vector A of the optical trap can be decomposed into plane waves, and the electric field vector A is decomposed into plane waves with as the basis, and a one-to-one correspondence relationship is established between each pixel point on the spatial light modulator and equation (3). In this basis of the plane wave decomposition, the momentum in the x direction can be expressed as equation (5) using the matrix quadratic form:

[0054]

[0055] where p x represents the momentum of the electric field vector A in the x direction, is the Planck constant, is a diagonal matrix, and can be expressed using equation (6):

[0056]

[0057] where p and q are coordinate subscript values, δ mp is the phase corresponding to m and p, and δ nq is the phase corresponding to n and q.

[0058] S120, transforming the decomposition matrix according to the preset vector spherical harmonic function and the beam distribution of the spatial light modulator to obtain a corresponding matrix expression.

[0059] The decomposition matrix is transformed according to the preset vector spherical harmonic function and the beam distribution of the spatial light modulator to obtain a corresponding matrix expression. Further, the beam distribution of the spatial light modulator can be obtained, and the decomposition matrix is basis transformed according to the beam distribution and the vector spherical harmonic function to obtain a matrix expression under plane wave decomposition.

[0060] In specific embodiments, step S120 comprises sub-steps: solving a linear transformation matrix of a sample scattering electric field of the beam distribution according to the vector spherical harmonic function; and transforming the decomposition matrix according to the linear transformation matrix to obtain a corresponding matrix expression.

[0061] For a general scattering problem, the sample scattering electric field B of the beam distribution can be expressed as a linear transformation of the electric field vector A, which is represented by formula (7):

[0062]

[0063] wherein, is a linear transformation matrix obtained by solving the sample scattering electric field B of a uniform spherical sample under the beam distribution under vector spherical harmonic function decomposition, and is a matrix obtained by solving the sample scattering electric field B of a uniform spherical sample under vector spherical harmonic function decomposition, that is, based on the classical Mie scattering solution. The matrix is also the linear transformation matrix obtained by solving the sample scattering electric field B of a uniform spherical sample under the beam distribution under vector spherical harmonic function decomposition.

[0064] Based on the obtained linear transformation matrix, the decomposition matrix is transformed; in the optical tweezer system, the incident light is axisymmetric about the propagation direction, so the momentum in any direction of the cross section is 0, and the size of the force F x is proportional to the momentum Based on formula (7), formula (5) is transformed to obtain a corresponding matrix expression as shown in formula (8).

[0065]

[0066] The obtained formula (8) is also a matrix expression. is the replacement symbol of the expression. is the transpose of the vector .

[0067] S130, calculating a Hermite matrix expression corresponding to the matrix expression according to the beam distribution of the spatial light modulator.

[0068] According to the light beam distribution of the spatial light modulator, a Hermite matrix expression corresponding to the matrix expression is calculated. Based on the phase shift of the plane wave of the sample in the spatial light modulator, the Hermite matrix expression corresponding to the matrix expression can be calculated by combining the phase shift with the matrix expression.

[0069] In specific embodiments, the step S130 comprises the sub-steps of: calculating a component calculation formula corresponding to the matrix expression according to the light beam distribution of the spatial light modulator; and comparing the stiffness coefficient of the optical trap according to the component calculation formula and the matrix expression to obtain the corresponding Hermite matrix expression.

[0070] In specific embodiments, the calculation of the component calculation formula corresponding to the matrix expression according to the light beam distribution of the spatial light modulator comprises: determining the phase shift of the plane wave according to the light beam distribution; and performing a shift superposition operation on the matrix expression according to the phase shift to obtain the corresponding component calculation formula.

[0071] First, the phase shift of the plane wave can be determined according to the light beam distribution of the sample. If the sample deviates from the origin For the plane wave, an additional phase shift needs to be introduced Based on the shift, a shift superposition operation is performed on the matrix expression, that is, the components of the electric field vector A are expressed in amplitude and phase as formula (9).

[0072]

[0073] where φ m,n is the phase loaded by the corresponding pixel of the spatial light modulator, and formula (9) is the component calculation formula.

[0074] In specific embodiments, the comparison of the stiffness coefficient of the optical trap according to the component calculation formula and the matrix expression to obtain the corresponding Hermite matrix expression comprises: expanding the matrix expression according to the component calculation formula to obtain a corresponding expanded expression; performing a superposition calculation on the expanded expression according to the pixel origin vibration of the plane wave corresponding to the light beam distribution to obtain a first-order expansion calculation formula of the stiffness coefficient of the optical trap near the origin of force; and comparing and superimposing the first-order expansion calculation formula of the stiffness coefficient of the optical trap near the origin of force with the initial calculation formula of the stiffness coefficient to obtain the corresponding Hermite matrix expression.

[0075] According to the obtained component calculation formula, the matrix expression is expanded to obtain an expanded expression as shown in formula (10).

[0076]

[0077] For the slight vibration of the sample near the origin, the corresponding stiffness coefficient κ can be obtained by superposition calculation based on the expansion expression. The first-order expansion calculation formula of the stiffness coefficient near the origin force is shown as formula (11).

[0078]

[0079] The first-order expansion calculation formula of the stiffness coefficient near the origin force is shown as formula (11).

[0080]

[0081] S140, according to the Hermite matrix expression, the stiffness coefficient of the optical trap is expanded to obtain the corresponding stiffness coefficient expansion expression.

[0082] According to the Hermite matrix expression, the stiffness coefficient of the optical trap is expanded to obtain the corresponding stiffness coefficient expansion expression. Further, according to the Hermite matrix expression, the stiffness coefficient of the optical trap is expanded to obtain the stiffness coefficient expansion expression as shown in formula (13):

[0083]

[0084] S150, according to the pixel symmetry rule, the Hermite matrix expression and the preset phase limiting condition, the phase of the spatial light modulator is optimized to obtain the optimized phase value.

[0085] According to the pixel symmetry rule, the Hermite matrix expression and the preset phase limiting condition, the phase of the spatial light modulator is optimized to obtain the optimized phase value.

[0086] According to the pixel symmetry rule, the Hermite matrix expression and the phase limiting condition, the phase of the spatial light modulator is optimized, and a set of phase values corresponding to each pixel (p, q) can be obtained after each optimization Wherein, for each individual pixel (p, q), assuming that the phases of other pixels are known, in order to maximize the coefficient value of formula (13), the phase thereof should satisfy the corresponding phase limiting condition, and the phase optimization formula in the phase limiting condition can be expressed by formula (14):

[0087]

[0088] In specific embodiments, the step S150 comprises the sub-steps of: randomly assigning an initial phase to each pixel on the spatial light modulator; calculating an extended expression of a diagonal matrix corresponding to a vector spherical harmonics according to a pixel symmetry rule; respectively extending the Hermite matrix expression and the phase optimization formula in the phase constraint condition according to the extended expression, to obtain a corresponding coefficient extended expression and a phase optimization extended formula; and performing phase optimization on the initial phase according to the coefficient extended expression and the phase optimization extended formula, to obtain an optimized phase value.

[0089] Specifically, in the first iteration optimization process, an initial phase is randomly assigned to each individual pixel (p, q) on the spatial light modulator (The initial phase does not need to be assigned again in the subsequent iteration optimization steps But the phase value obtained in the last iteration optimization is used for optimization again).

[0090] Further, the extended expression of the diagonal matrix corresponding to the vector spherical harmonics is calculated according to the pixel symmetry rule,

[0091] Due to the symmetry of the spatial light modulator pixels, according to this pixel symmetry rule, k y,q = k x,q = k q ; according to this pixel symmetry rule, the diagonal matrix shown in formula (6) is extended, and the y-direction expression corresponding to formula (6) is shown in formula (15):

[0092]

[0093] According to the extended expression, the Hermite matrix expression and the phase optimization formula in the phase constraint condition are respectively extended, the Hermite matrix expression corresponding to formula (12) is extended, and the obtained coefficient extended expression is shown in formula (16):

[0094]

[0095] The phase optimization formula (single-pixel optimal phase expression) corresponding to formula (14) is extended, and the obtained phase optimization extended formula is shown in formula (17):

[0096]

[0097] The light intensity distribution of the incident light is center-symmetric along the cross section, so A m,n = A n,m ; in order to keep formula (14) matched with formula (17), φ m,n = φ n,mMeanwhile, in order to keep the momentum of the incident light as 0, φ m,n = φ -m+1,-n+1 Under the above defined conditions, the corresponding optimized phase value can be calculated based on formula (17). The phase iterative optimization based on the above pixel symmetry rule can greatly reduce the calculation amount.

[0098] S160, generating a corresponding control instruction according to the optimized phase value and sending it to the spatial light modulator to control the phase of the spatial light modulator.

[0099] According to the optimized phase value, a corresponding control instruction is generated and sent to the spatial light modulator to control the phase of the spatial light modulator. Through the above steps, the optimized phase of each pixel After obtaining the optimized phase value, a corresponding control instruction is generated based on the optimized phase value and sent to the spatial light modulator. Specifically, a corresponding gray scale map can be obtained based on the optimized phase value, and a control instruction is generated based on the gray scale map and sent to the spatial light modulator. After receiving the control instruction, the spatial light modulator loads the gray scale map set in the control instruction, that is, controls the phase of the spatial light modulator. By loading the gray scale map corresponding to the optimized phase value in the spatial light modulator, the optimization of the stiffness coefficient of the specific sample optical trap can be realized.

[0100] S170, according to the light beam distribution of the spatial light modulator after phase control, the coefficient value of the stiffness coefficient expansion expression is recalculated.

[0101] According to the light beam distribution of the spatial light modulator after phase control, the coefficient value of the stiffness coefficient expansion expression is recalculated. After phase control, the stiffness coefficient expansion expression can be recalculated by the light beam distribution of the spatial light modulator. The actual value obtained is input into formula (16), and the coefficient value of the stiffness coefficient expansion expression can be calculated.

[0102] S180, if the coefficient value or the number of optimizations meets the preset iterative optimization condition, return to the step of performing phase optimization on the spatial light modulator to perform phase iterative optimization on the spatial light modulator.

[0103] If the coefficient value or the number of optimizations meets the preset iterative optimization condition, the step S150 is returned to perform phase iterative optimization on the spatial light modulator. Further, it is judged whether the current calculated coefficient value meets the iterative optimization condition, and whether the number of optimizations meets the iterative optimization condition. Wherein, it is judged whether the current calculated coefficient value is increased compared with the coefficient value before optimization, if yes, it is determined that the iterative optimization condition is met; otherwise, it is determined that the iterative optimization condition is not met. The number of optimizations is the number of phase optimizations on the spatial light modulator through the above steps, and it is judged whether the number of optimizations is greater than the number threshold set in the iterative optimization condition, if yes, it is determined that the iterative optimization condition is met; otherwise, it is determined that the iterative optimization condition is not met.

[0104] If the coefficient value or the number of optimizations meets the iterative optimization condition, the phase optimization on the spatial light modulator is continued, that is, the step S150 is returned. At this time, the current used phase value is taken as the initial phase for iterative optimization, that is, except for the initial phase randomly allocated for the first iterative optimization, the initial phase does not need to be randomly allocated again for subsequent iterative optimization.

[0105] If the coefficient value and the number of optimizations do not meet the iterative optimization condition, the above iterative optimization processing flow is terminated, and the current obtained phase value is used as the optimal phase value finally optimized.

[0106] In the phase control method of the holographic optical tweezer potential well stiffness disclosed in the above embodiment, the method comprises: calculating a decomposition matrix formula, a matrix expression and an Hermite matrix expression according to input system configuration parameters, expanding the stiffness coefficient of the optical trap through the Hermite matrix expression to obtain a stiffness coefficient expansion expression, performing phase optimization on the spatial light modulator based on a pixel symmetry rule to obtain an optimized phase value, generating a control instruction through the optimized phase value and sending the control instruction to the spatial light modulator, and recalculating the coefficient value of the stiffness coefficient expansion expression. If the coefficient value or the number of optimizations meets the iterative optimization condition, the step of performing phase optimization on the spatial light modulator is returned. The phase control method of the optical tweezer potential well stiffness can solve the Hermite matrix expression and the stiffness coefficient expansion expression according to the system configuration parameters, modulate the phase of the light beam by generating the control instruction, maximize the coefficient value of the stiffness coefficient through phase iterative optimization, and improve the application effect of the phase of the potential well stiffness.

[0107] The embodiment of the present application also provides a holographic optical tweezer potential well stiffness phase control device, which can be configured in a controller, the controller is in communication connection with a spatial light modulator in a phase control system, and the holographic optical tweezer potential well stiffness phase control device is used for executing any one of the above-mentioned holographic optical tweezer potential well stiffness phase control methods. Specifically, please refer to Figure 3, Figure 3 A schematic block diagram of a holographic optical tweezers potential stiffness phase control device provided for an embodiment of the present application.

[0108] As shown in Figure 3 The holographic optical tweezers potential stiffness phase control device 100 includes a decomposition unit 110, a transformation unit 120, a calculation unit 130, an expansion unit 140, a phase optimization unit 150, a control instruction sending unit 160, a coefficient value calculation unit 170, and a return execution unit 180.

[0109] The decomposition unit 110 is configured to, if receiving an input system configuration parameter, perform plane wave decomposition on an electric field of an optical trap according to the system configuration parameter to obtain a corresponding decomposition matrix expression.

[0110] The transformation unit 120 is configured to transform the decomposition matrix expression according to a preset vector spherical harmonic function and a beam distribution of the spatial light modulator to obtain a corresponding matrix expression.

[0111] The calculation unit 130 is configured to calculate a Hermite matrix expression corresponding to the matrix expression according to the beam distribution of the spatial light modulator.

[0112] The expansion unit 140 is configured to expand a stiffness coefficient of the optical trap according to the Hermite matrix expression to obtain a corresponding stiffness coefficient expansion expression.

[0113] The phase optimization unit 150 is configured to perform phase optimization on the spatial light modulator according to a pixel symmetry rule, the Hermite matrix expression, and a preset phase limitation condition to obtain an optimized phase value.

[0114] The control instruction sending unit 160 is configured to generate a corresponding control instruction according to the optimized phase value and send the control instruction to the spatial light modulator to perform phase control on the spatial light modulator.

[0115] The coefficient value calculation unit 170 is configured to recalculate a coefficient value of the stiffness coefficient expansion expression according to a beam distribution of the spatial light modulator after phase control.

[0116] The return execution unit 180 is configured to, if the coefficient value or the number of optimizations satisfies a preset iterative optimization condition, return to perform the step of phase optimization on the spatial light modulator to perform phase iterative optimization on the spatial light modulator.

[0117] In the phase control device for holographic optical tweezers potential well stiffness provided by the embodiment of the application, the phase control method for holographic optical tweezers potential well stiffness is applied, the decomposition matrix, the matrix expression and the Hermite matrix expression are calculated according to the input system configuration parameters, the stiffness coefficient expansion expression is obtained by expanding the stiffness coefficient of the optical trap through the Hermite matrix expression, the optimized phase value is obtained by performing phase optimization on the spatial light modulator based on the pixel symmetry rule, the control instruction is generated through the optimized phase value and is sent to the spatial light modulator, and the coefficient value of the stiffness coefficient expansion expression is recalculated, and if the coefficient value or the optimization times satisfies the iterative optimization condition, the step of performing phase optimization on the spatial light modulator is returned to be executed. The phase control method for optical tweezers potential well stiffness can solve the Hermite matrix expression and the stiffness coefficient expansion expression according to the system configuration parameters, phase modulate the light beam by generating the control instruction, and maximize the coefficient value of the stiffness coefficient through phase iterative optimization, thereby improving the application effect of the phase of the potential well stiffness.

[0118] The embodiment of the application further provides a phase control system for holographic optical tweezers potential well stiffness. Figure 2 As shown in the figure, the system comprises a controller 1, a laser 2, a beam expander 3, a half-wave plate 4, a polarization fraction cubic mirror 5, a spatial light modulator 6, an objective lens 7 and a camera 8. The laser 2 is used to emit a laser beam, the beam expander 3 is arranged downstream of the laser 2, the polarization fraction cubic mirror 5 is arranged downstream of the beam expander 3, and the half-wave plate 4 is arranged between the polarization fraction cubic mirror 5 and the beam expander 3. The spatial light modulator 6 is arranged downstream of the polarization fraction cubic mirror 5, a dichroic mirror 9 is arranged downstream of the spatial light modulator 6, the objective lens 7 and the camera 8 are arranged on the two sides of the dichroic mirror 9 respectively, and the controller 1 is in communication connection with the spatial light modulator 6. The laser beam emitted by the laser 2 passes through the beam expander 3 for beam expansion, and then passes through the half-wave plate 4 for filtering and is incident into the polarization fraction cubic mirror 5 to obtain a polarized light beam. The polarization fraction cubic mirror 5 irradiates the spatial light modulator 6, the spatial light modulator 6 adjusts the light beam reflected from the spatial light modulator 6 to the dichroic mirror 9 by phase control, the dichroic mirror 9 refracts the light beam reflected from the spatial light modulator 6 and emits it to the objective lens 7, the objective lens 7 irradiates a sample to obtain a reflected light beam, the reflected light beam passes through the dichroic mirror 9 and is collected by the camera 8, and then the image of the sample can be obtained through the camera. During the imaging of the sample, the controller 1 can output the control instruction to the spatial light modulator 6 to adjust the phase of the light beam reflected from the spatial light modulator 6 to the dichroic mirror 9.

[0119] The phase control device for holographic optical tweezers potential well stiffness can be realized in the form of a computer program, and the computer program can run on a computer device as shown in the figure. Figure 4 ​

[0120] Please refer to Figure 4 , Figure 4 is a schematic block diagram of a computer device provided by an embodiment of the present application. The computer device can be a controller for performing a phase control method of holographic optical tweezer potential well stiffness to perform spatial light phase control.

[0121] Please refer to Figure 4 , the computer device 500 includes a processor 502, a memory and a communication interface 505 connected through a communication bus 501, wherein the memory can include a storage medium 503 and an internal memory 504.

[0122] The storage medium 503 can store an operating system 5031 and a computer program 5032. The computer program 5032, when executed, can cause the processor 502 to perform the phase control method of holographic optical tweezer potential well stiffness, wherein the storage medium 503 can be a volatile storage medium or a non-volatile storage medium.

[0123] The processor 502 is configured to provide computing and control capabilities to support the operation of the entire computer device 500.

[0124] The internal memory 504 provides an environment for the execution of the computer program 5032 in the storage medium 503, and the computer program 5032, when executed by the processor 502, can cause the processor 502 to perform the phase control method of holographic optical tweezer potential well stiffness.

[0125] The communication interface 505 is configured to perform network communication, such as providing transmission of data information, etc. Those skilled in the art can understand that Figure 4 The structure shown in the figure is only a block diagram of part of the structure related to the present application scheme, and does not constitute a limitation on the computer device 500 to which the present application scheme is applied. The specific computer device 500 can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0126] The processor 502 is configured to run the computer program 5032 stored in the memory to implement the corresponding functions in the phase control method of holographic optical tweezer potential well stiffness described above.

[0127] Those skilled in the art can understand that Figure 4 The embodiments of the computer device shown in the figure do not constitute a limitation on the specific structure of the computer device. In other embodiments, the computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement. For example, in some embodiments, the computer device can only include a memory and a processor, and in such embodiments, the structure and function of the memory and the processor are consistent with those of the embodiments shown in Figure 4 , which will not be described here.

[0128] It should be appreciated that in an embodiment of the present application, the processor 502 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0129] In another embodiment of the present application, a computer readable storage medium is provided. The computer readable storage medium can be a volatile or non-volatile computer readable storage medium. The computer readable storage medium stores a computer program, wherein the computer program is executed by a processor to implement the steps included in the holographic optical tweezers potential well stiffness phase control method described above.

[0130] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the devices, apparatuses and units described above can refer to the corresponding processes in the foregoing method embodiments, which will not be described here. Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been described in the foregoing description in a general manner. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0131] In several embodiments provided by the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other manners. For example, the embodiments of the apparatus described above are merely schematic, and the division of the units is merely logical function division, and there can be other division manners in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electric, mechanical or in other forms.

[0132] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they can be located in one place, or distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0133] In addition, the functional units in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit. The integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0134] The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a computer readable storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned computer readable storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0135] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for phase control of holographic optical tweezer potential well stiffness, characterized in that, The method is applied to a controller which is communicatively connected with a spatial light modulator in a phase control system, and the method comprises: If the input system configuration parameters are received, the electric field of the optical trap is subjected to plane wave decomposition according to the system configuration parameters to obtain a corresponding decomposition matrix formula; The decomposition matrix formula is transformed according to a preset vector spherical harmonic function and a beam distribution of the spatial light modulator to obtain a corresponding matrix expression; An Hermite matrix expression corresponding to the matrix expression is calculated according to the beam distribution of the spatial light modulator; The stiffness coefficient of the optical trap is unfolded according to the Hermite matrix expression to obtain a corresponding stiffness coefficient unfolding expression; The spatial light modulator is subjected to phase optimization according to a pixel symmetry rule, the Hermite matrix expression and a preset phase limitation condition to obtain an optimized phase value; A corresponding control instruction is generated according to the optimized phase value and is sent to the spatial light modulator to control the phase of the spatial light modulator; The coefficient value of the stiffness coefficient unfolding expression is recalculated according to the beam distribution of the spatial light modulator after phase control; If the coefficient value or the optimization times satisfies a preset iterative optimization condition, the step of optimizing the phase of the spatial light modulator is returned to perform phase iterative optimization on the spatial light modulator.

2. The method of phase control of holographic optical tweezer potential well stiffness according to claim 1, wherein, The method of decomposing the electric field of the optical trap according to the system configuration parameters to obtain a corresponding decomposition matrix formula comprises: The center coordinates of each pixel point in the spatial light modulator are determined according to the imaging resolution and the pixel size in the system configuration parameters; The base of the plane wave decomposition is determined by the focal length in the system configuration parameters and the center coordinates; The electric field vector of the optical trap is subjected to plane wave decomposition according to the base of the plane wave decomposition to obtain a corresponding decomposition matrix formula.

3. The method of phase control of holographic optical tweezer potential well stiffness according to claim 1, wherein, The method of transforming the decomposition matrix formula according to a preset vector spherical harmonic function and a beam distribution of the spatial light modulator to obtain a corresponding matrix expression further comprises: The sample scattering electric field of the beam distribution is solved according to the vector spherical harmonic function to obtain a linear transformation matrix; The decomposition matrix formula is transformed according to the linear transformation matrix to obtain a corresponding matrix expression.

4. The method of phase control of holographic optical tweezer potential well stiffness according to claim 1, wherein, The method of calculating an Hermite matrix expression corresponding to the matrix expression according to the beam distribution of the spatial light modulator comprises: A component calculation formula corresponding to the matrix expression is calculated according to the beam distribution of the spatial light modulator; The stiffness coefficient of the optical trap is compared according to the component calculation formula and the matrix expression to obtain a corresponding Hermite matrix expression.

5. The method of phase control of holographic optical tweezer potential well stiffness according to claim 4, wherein, The method of calculating a component calculation formula corresponding to the matrix expression according to the beam distribution of the spatial light modulator comprises: The phase offset of the plane wave is determined according to the beam distribution; The matrix expression is subjected to offset superposition operation according to the phase offset to obtain a corresponding component calculation formula.

6. The method of phase control of holographic optical tweezer potential well stiffness according to claim 4, wherein, The method of comparing the stiffness coefficient of the optical trap according to the component calculation formula and the matrix expression to obtain a corresponding Hermite matrix expression comprises: According to the component calculation formula, the matrix expression is unfolded to obtain a corresponding unfolded expression; According to pixel origin vibration of the corresponding plane wave of the light beam distribution, the unfolded expression is superimposed to obtain a first-order unfolded calculation formula of the stiffness coefficient of the optical trap near the origin force; The first-order unfolded calculation formula of the stiffness coefficient near the origin force is compared and superimposed with the initial calculation formula of the stiffness coefficient to obtain a corresponding Hermite matrix expression.

7. The method of claim 1, wherein the holographic optical tweezer potential well stiffness is phase controlled. The phase optimization of the spatial light modulator is performed according to the pixel symmetry rule, the Hermite matrix expression and a preset phase limiting condition to obtain an optimized phase value, which comprises: An initial phase is randomly assigned to each pixel on the spatial light modulator; An extended expression of a diagonal matrix corresponding to a vector spherical harmonic function is calculated according to the pixel symmetry rule; According to the extended expression, the Hermite matrix expression and a phase optimization formula in the phase limiting condition are respectively extended to obtain a corresponding coefficient extension expression and a phase optimization extension formula; The initial phase is phase-optimized according to the coefficient extension expression and the phase optimization extension formula to obtain an optimized phase value.

8. An apparatus for phase control of holographic optical tweezer potential well stiffness, comprising: a holographic optical tweezer potential well; and a phase control device configured to control the stiffness of the holographic optical tweezer potential well. The device is arranged in a controller, the controller is in communication connection with a spatial light modulator in a phase control system, and the phase control device of the holographic optical tweezers potential well stiffness is used for executing the phase control method of the holographic optical tweezers potential well stiffness according to any one of claims 1-7, and the device comprises: A decomposition unit is configured to, if receiving the input system configuration parameter, perform plane wave decomposition on the electric field of the optical trap according to the system configuration parameter to obtain a corresponding decomposition matrix expression; A transformation unit is configured to transform the decomposition matrix expression according to a preset vector spherical harmonic function and the light beam distribution of the spatial light modulator to obtain a corresponding matrix expression; A calculation unit is configured to calculate a Hermite matrix expression corresponding to the matrix expression according to the light beam distribution of the spatial light modulator; An unfolding unit is configured to unfold the stiffness coefficient of the optical trap according to the Hermite matrix expression to obtain a corresponding stiffness coefficient unfolded expression; A phase optimization unit is configured to perform phase optimization of the spatial light modulator according to the pixel symmetry rule, the Hermite matrix expression and a preset phase limiting condition to obtain an optimized phase value; A control instruction sending unit is configured to generate a corresponding control instruction according to the optimized phase value and send the control instruction to the spatial light modulator to perform phase control on the spatial light modulator; A coefficient value calculation unit is configured to recalculate the coefficient value of the stiffness coefficient unfolded expression according to the light beam distribution of the spatial light modulator after phase control; A return execution unit is configured to, if the coefficient value or the optimization times satisfies a preset iteration optimization condition, return to execute the step of performing phase optimization on the spatial light modulator to perform phase iteration optimization on the spatial light modulator.

9. A system for phase control of holographic optical tweezer potential well stiffness, comprising: The system comprises a controller, a laser, a beam expander, a half-wave plate, a polarization fraction cube, a spatial light modulator, an objective lens and a camera; The laser is used for emitting a laser beam, the beam expander is arranged downstream of the laser, the polarization fraction cube is arranged downstream of the beam expander, and the half-wave plate is arranged between the polarization fraction cube and the beam expander; The spatial light modulator is arranged downstream of the polarization fraction cube, a dichroic mirror is arranged downstream of the spatial light modulator, and the objective lens and the camera are arranged on two sides of the dichroic mirror, respectively; The controller is in communication connection with the spatial light modulator, and the controller comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete communication with each other through the communication bus; The memory is used for storing a computer program; When the processor executes the computer program stored in the memory, the steps of the phase control method of the holographic optical tweezers potential well rigidity are realized.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the phase control method of the holographic optical tweezers potential well rigidity.

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