Method for carrying out chiral parameter detection by applying optical spin Hall displacement

Abstract

The invention provides a method for carrying out chiral parameter detection by applying optical spin Hall displacement. The method comprises the following steps: acquiring a dielectric constant, magnetic conductivity and a particle radius of a chiral nanoparticle to be detected; according to the dielectric constant, the magnetic conductivity and the particle radius of the to-be-measured chiral nano-particles, determining the light spin Hall displacement of the chiral nano-particles with different chiral parameters under the quasi-dual symmetry condition so as to determine the contrast mapping relation between the light spin Hall displacement and the chiral parameters; under the condition that circularly polarized light irradiates the to-be-measured chiral nanoparticles and generates a light spin Hall effect, the wavelength of incident light is adjusted until quasi-dual symmetry is met, so that the maximization of light spin Hall displacement is realized; and determining the chiral parameter of the to-be-detected chiral nanoparticle under the maximum optical spin Hall displacement according to the contrast mapping relation between the optical spin Hall displacement and the chiral parameter. According to the method, the chiral parameters of the chiral nanoparticles can be intuitively judged according to the magnitude of the spin Hall displacement peak value.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-optics, and particularly relates to a method for detecting chiral parameters by applying the optical spin Hall shift. Background Art

[0002] Chirality is generally a geometric property. When an object cannot coincide with its mirror image, we say that this object has a chiral structure. Of course, chiral features can also exist in some knotted and twisted fields, such as left- and right-handed circularly polarized light or fluid vortices. For a long time, chiral electromagnetic fields have been used to characterize chiral substances, but recently they have also been used in the design of enantioselective biosensing, enantiomer discrimination, asymmetric catalysis, and nonlinear spectroscopic imaging. When nanostructures have chiral properties, they can exhibit high optical activity and excite highly twisted chiral near-fields.

[0003] To study the characteristics of these near-fields, a common method is to use CD (circular dichroism) spectroscopy. Since chiral structures exhibit interactions related to the polarization of light, optical analysis techniques are very suitable for detecting and characterizing chirality. Chiral objects are optically active, which means that their enantiomers respond differently to different polarized lights. One type of optical activity is dichroism, in which the absorption of light by chiral objects is polarization-dependent.

[0004] As Figure 1 shown, first, natural light is passed through a polarizer to form linearly polarized light, and then through an optical modulator to form circularly polarized light. When chiral molecules interact with left- and right-handed circularly polarized lights, the CD spectrum can sense the differential absorption. Circularly polarized light itself is chiral because it propagates through two linear components with a phase difference of ±π / 2, thus generating a three-dimensional circular helical motion. Chiral molecules preferentially eliminate the light that matches the chirality of the molecule. Although only the absorption component in the extinction coefficient of small molecules is important, the scattering component in the extinction coefficient of large nanoparticles and macromolecules can significantly contribute to the measured CD.

[0005] However, the extinction difference between left- and right-handed circularly polarized lights in the CD spectrum may sometimes lead to the appearance of a cancellation effect. Ultimately, the peak value and the positive or negative value of the CD spectrum cannot well reflect the chiral information of the near-field. Summary of the Invention

[0006] The present invention provides a method for detecting chiral parameters by applying the optical spin Hall shift, so as to solve the problem that in the prior art, due to the cancellation effect caused by the extinction difference between left- and right-handed circularly polarized lights in the CD spectrum, the peak value and the positive or negative value of the final CD spectrum cannot well reflect the chiral information of the near-field.

[0007] In a first aspect, the present invention provides a method for detecting chiral parameters by applying the optical spin Hall displacement, including:

[0008] Obtaining the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured;

[0009] Determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the control mapping relationship between the optical spin Hall displacement and the chiral parameters;

[0010] When circularly polarized light irradiates the chiral nanoparticles to be measured and generates the optical spin Hall effect, adjusting the incident light wavelength until quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement;

[0011] Determining the chiral parameters of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the control mapping relationship between the optical spin Hall displacement and the chiral parameters.

[0012] Optionally, the determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the control mapping relationship between the optical spin Hall displacement and the chiral parameters, includes:

[0013] Constructing the expressions of the first scattering coefficient and the second scattering coefficient :

[0014] ;

[0015] where n is the first summation index; m is the second summation index; is the first expansion coefficient of right-handed polarized light; is the second expansion coefficient of right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying:

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation; η r is the fifth intermediate variable; ; is the permittivity of the environmental medium; μ is the magnetic permeability of the environmental medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation; a is the radius of the chiral nanoparticle; k is the wave number in the environmental medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - hand circularly polarized light; ; k2 is the wave number of the right - hand circularly polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum; i is the imaginary unit; δ m,1 is the Kronecker symbol;

[0022] Construct the contrast mapping relationship expression between the optical spin - Hall displacement Δ SH and the chirality parameter:

[0023] ;

[0024] where θ is the second component of the coordinate vector in the spherical coordinate system; Re(·) represents taking the real part of the value; is the second scattering coefficient when m = 1; is the associated Legendre polynomial when m = 1; S1 is the first scattering matrix amplitude; S2 is the second scattering matrix amplitude; is the first scattering coefficient when m = 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of the value.

[0025] Optionally, the method for determining the optical spin - Hall displacement of chiral nanoparticles with different chirality parameters under the quasi - dual - symmetry condition according to the permittivity, magnetic permeability and particle radius of the to - be - measured chiral nanoparticles to determine the contrast mapping relationship between the optical spin - Hall displacement and the chirality parameter further includes:

[0026] Construct the expression of the transfer function T:

[0027] ;

[0028] Among them, when the quasi-dual symmetry condition is satisfied, T is 0.

[0029] In a second aspect, the present invention provides a system for detecting chiral parameters by applying the optical spin Hall displacement, including:

[0030] An acquisition module for acquiring the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured;

[0031] A first determination module for determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the quasi-dual symmetry condition according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters;

[0032] An adjustment module for adjusting the incident light wavelength until the quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement when circularly polarized light irradiates the chiral nanoparticles to be measured and generates the optical spin Hall effect;

[0033] A second determination module for determining the chiral parameters of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the mapping relationship between the optical spin Hall displacement and the chiral parameters.

[0034] Optionally, the first determination module includes:

[0035] A first construction unit for constructing the expressions of the first scattering coefficient and the second scattering coefficient :

[0036] ;

[0037] where n is the first summation index; m is the second summation index; is the first expansion coefficient of right-handed polarized light; is the second expansion coefficient of right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying:

[0038] ;

[0039] ;

[0040] ;

[0041] ;

[0042] ;

[0043] is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation; η r is the fifth intermediate variable; ; is the permittivity of the environmental medium; μ is the magnetic permeability of the environmental medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation; a is the radius of the chiral nanoparticle; k is the wave number in the environmental medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - hand circularly polarized light; ; k2 is the wave number of the right - hand circularly polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum; i is the imaginary unit; δ m,1 is the Kronecker symbol;

[0044] The second construction unit is used to construct the expression of the optical spin - Hall displacement Δ SH and the mapping relationship expression between the chirality parameter:

[0045] ;

[0046] where θ is the second component of the coordinate vector in the spherical coordinate system; Re(·) represents taking the real part of the value; is the second scattering coefficient when m = 1; is the associated Legendre polynomial when m = 1; S1 is the first scattering matrix amplitude; S2 is the second scattering matrix amplitude; is the first scattering coefficient when m = 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of the value.

[0047] Optionally, the first determination module further includes:

[0048] The third construction unit is used to construct the expression of the transfer function T:

[0049] ;

[0050] where when the quasi - dual symmetry condition is satisfied, T is 0.

[0051] In a third aspect, the present invention provides a computer device, including a processor and a memory; wherein, when the processor executes the computer program stored in the memory, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement described in the first aspect are implemented.

[0052] In a fourth aspect, the present invention provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement described in the first aspect are implemented.

[0053] In a fifth aspect, the present invention provides a computer program product, including computer-executable instructions or a computer program, when the computer-executable instructions or the computer program are executed by a processor, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement described in the first aspect are implemented.

[0054] The present invention provides a method for detecting chiral parameters by applying the optical spin Hall displacement. Since the spin Hall displacement is very sensitive to the dielectric constant, magnetic permeability and particle radius of chiral nanoparticles, it has the advantage of high sensitivity when used for chiral detection; determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters, and the chiral parameters of chiral nanoparticles can be intuitively judged from the peak value of the spin Hall displacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 It is a schematic diagram of a conventional spectrum for detecting chirality provided by an embodiment of the present invention;

[0057] Figure 2 It is a flowchart of a method for detecting chiral parameters by applying the optical spin Hall displacement provided by an embodiment of the present invention;

[0058] Figure 3 It is a schematic model diagram of the spin Hall displacement caused by chiral nanoparticles under circularly polarized light incidence provided by an embodiment of the present invention;

[0059] Figure 4 It is a distribution diagram of the peak value of the optical spin Hall displacement of chiral nanoparticles and the logarithm of the transfer function provided by an embodiment of the present invention;

[0060] Figure 5The streamline of the near-field orbital momentum density and the corresponding orbital momentum density intensity distribution map of the chiral nanoparticles provided by the embodiments of the present invention under different chiral parameters;

[0061] Figure 6 The structural schematic diagram of a system for detecting chiral parameters by applying the optical spin Hall shift provided by the embodiments of the present invention. Specific embodiments

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0063] Embodiment 1

[0064] As Figure 2 shown, this embodiment provides a method for detecting chiral parameters by applying the optical spin Hall shift, including:

[0065] Step 101, obtain the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured.

[0066] In this step, the particle radius can be obtained by using a nanoparticle size analyzer, and the measurable range of the nanoparticle size analyzer is 0.3 nanometers to 10 micrometers. Regarding the dielectric constant and magnetic permeability, they can be obtained by using an impedance analyzer.

[0067] Step 102, determine the optical spin Hall shift of the chiral nanoparticles with different chiral parameters under the quasi-dual symmetry condition according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall shift and the chiral parameters.

[0068] As Figure 3 shown, the spin Hall shift caused by the incident circularly polarized light on the chiral nanoparticles, the incident right-handed circularly polarized light ; where E0 is the amplitude of the incident wave; is the unit vector in the x direction of the first component of the coordinate vector in the space rectangular coordinate system; is the unit vector in the y direction of the second component of the coordinate vector in the space rectangular coordinate system; i is the imaginary symbol; k is the wave number in the environmental medium; ω is the angular frequency of the incident wave; z is the unit vector in the z direction of the third component of the coordinate vector in the space rectangular coordinate system; t is the time.

[0069] For the constitutive relation under normal circumstances For such substances, they usually do not have optical activity. There are many constitutive relations in chiral media with optical activity, but most of them have been proven to be equivalent to each other. In this embodiment, the Condon-Rosenfeld constitutive relation is adopted:

[0070] .

[0071] where D is the electric displacement vector of the chiral nanoparticle; B is the magnetic induction intensity of the chiral nanoparticle; is the dielectric constant of the chiral nanoparticle; κ is the chirality parameter of the chiral nanoparticle (usually taken between -1 and 1); is the dielectric constant in vacuum; μ0 is the magnetic permeability in vacuum; H is the magnetic field strength; E is the electric field strength; μ c is the magnetic permeability of the chiral nanoparticle.

[0072] Construct a scattering field model of the chiral nanoparticle. The scattering field is a key physical quantity for calculating the optical spin Hall displacement. The scattering field of the chiral nanoparticle is given by the Mie scattering theory:

[0073] .

[0074] .

[0075] .

[0076] .

[0077] where E ip is the incident wave electric field component; H ip is the incident wave magnetic field component; n is the first summation index; m is the second summation index; in this embodiment, both n and m can be assigned values according to actual needs. and are both the first kind of spherical harmonic vector wave functions; in this embodiment, the coordinate vector in spherical coordinates is represented by three components (r, θ, φ); r is the second component of the coordinate vector in the spherical coordinate system; E s represents the electric field scattering field; is the first scattering coefficient; is the second scattering coefficient; and are both the third kind of spherical harmonic vector wave functions; H s represents the magnetic field scattering field; and are both the expansion coefficients of the incident wave; p represents the incident polarization state. When right-handed polarized light is incident:

[0078] .

[0079] δ m,1 is the Kronecker symbol.

[0080] Inside the chiral nanoparticles, any optical field entering the chiral medium can be divided into two field components with different polarizations, left-handed and right-handed. The two components have different amplitudes, phases, and wavenumbers. The amplitudes and phases are described by the expansion coefficients A mn and B mn . The wavenumbers are affected by the chirality of the medium. The wavenumbers of the left-handed and right-handed components are and respectively. Therefore, the internal field can be expressed as:

[0081] .

[0082] .

[0083] where E int is the electric field inside the chiral nanoparticles; H int is the magnetic field inside the chiral nanoparticles.

[0084] According to the boundary conditions and , substituting the above expressions of the internal field and the external field, the scattering coefficients and can be obtained.

[0085] Exemplarily, the expressions of the first scattering coefficient and the second scattering coefficient are constructed as follows:

[0086] .

[0087] where is the first expansion coefficient of the right-handed polarized light; is the second expansion coefficient of the right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying:

[0088] .

[0089] .

[0090] .

[0091] .

[0092] is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation, ; is the derivative of; η r is the fifth intermediate variable; ; is the permittivity of the environmental medium; μ is the magnetic permeability of the environmental medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation, ; is the derivative of; a is the radius of the chiral nanoparticle; k is the wave number in the environmental medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - hand circularly polarized light; ; k2 is the wave number of the right - hand circularly polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum.

[0093] The expression of the optical spin - Hall displacement in the chiral sphere model is derived from the Mie scattering theory. Since the spin - Hall displacement is a function of the scattering angle, when adjusting the chirality parameter, this embodiment only focuses on the peak value of the spin - Hall displacement under this set of parameters, which can clearly observe the change of the peak value. However, in addition to the chirality parameter, the dual symmetry of the system is also an important factor affecting the spin - Hall displacement. The dual symmetry can be described by the transfer function. The definition formula of the transfer function is , that is, the ratio of the energy of the part of the scattered field with the opposite helicity to the incident field to the energy of the part with the same helicity. After substituting the expression of the scattered field, it is:

[0094] .

[0095] Among them, when the quasi - dual symmetry condition is satisfied, T is 0 (that is, when approaching the quasi - dual symmetry infinitely, the magnitude of the transfer function will approach 0 infinitely).

[0096] The optical spin - Hall effect originates from the momentum conversion between the spin angular momentum and the orbital angular momentum when the light beam propagates in a medium with a refractive index gradient. Its final manifestation is the lateral displacement of the interaction body's perception position, which can be expressed as:

[0097] .

[0098] Among them, P φ is the component of the Poynting vector of the scattered wave in the direction of the third component of the coordinate vector in the spherical coordinate system; P is the component of the Poynting vector of the scattered wave in the direction of the first component of the coordinate vector in the spherical coordinate system; r is the unit vector in the direction of the third component of the coordinate vector in the spherical coordinate system. . is the third component of the coordinate vector in the spherical coordinate system direction.

[0099] Exemplarily, construct the expression of the mapping relationship between the optical spin Hall displacement Δ SH and the chirality parameter:

[0100] .

[0101] Among them, θ is the second component of the coordinate vector in the spherical coordinate system, that is, the scattering angle; Re(·) represents taking the real part of the value; is the second scattering coefficient when m takes 1; is the associated Legendre polynomial when m takes 1; S1 is the amplitude of the first scattering matrix; S2 is the amplitude of the second scattering matrix; is the first scattering coefficient when m takes 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of the value.

[0102] When light interacts with a medium, the conservation of the angular momentum of light causes a coupling between the spin degree of freedom of photons and their orbital motion. This spin-orbit interaction is the source of the spin Hall displacement. The Dirac form of Maxwell's equations can be used to describe the local spin and orbital momenta and their spin-orbit interactions, and its form is:

[0103] .

[0104] Among them, c is the speed of light in vacuum; and are both Dirac matrices, is the wave function of the electric and magnetic fields, ; is the momentum operator ; V is the optical potential caused by the dielectric medium. The orbital momentum density is defined by and can be used to characterize the trajectory of photons. Its specific expression is:

[0105] .

[0106] Among them, Im(·) takes the imaginary part of the value.

[0107] Step 103: When circularly polarized light irradiates the chiral nanoparticles to be measured and generates the optical spin Hall effect, adjust the wavelength of the incident light until quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement.

[0108] Adjust the wavelength to make the transfer function in Step 102 reach the minimum value to satisfy the quasi-dual symmetry condition. Substitute the parameters and scattering coefficient at this time into the expression of the spin Hall displacement, and the optical spin Hall displacement under different chiral parameters can be obtained.

[0109] Since the optical spin Hall displacement is usually very weak, quantum weak measurement technology is generally used to observe the optical spin Hall displacement. Weak measurement generally includes three steps: pre-selection, weak coupling, and post-selection. First, the incident light beam passes through the first polarizer to reach the pre-selected state, then weak coupling occurs at the air-glass interface, and finally the post-selection is completed through the second polarizer to obtain the eigenvalue of the scattering field. The projection directions of the two polarizers are opposite. By this method, the optical spin Hall displacement can reach a measurable accuracy.

[0110] Step 104: Determine the chiral parameter of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the mapping relationship between the optical spin Hall displacement and the chiral parameter.

[0111] When dual symmetry is satisfied, the magnitude of the transfer function is 0. In this embodiment, a silicon sphere with a relative permittivity of 3.55 2 , a magnetic permeability of 1, and a radius of 131 nm is used as the research object (the environmental medium is vacuum). When the chiral parameter is 0 (that is, there is no chirality), dual symmetry is satisfied when circularly polarized light with a wavelength of about 1068 nm is incident (here it is right-handed polarized light). At this time, the peak value of the optical spin Hall displacement reaches the maximum, about 1.9 times the wavelength, as Figure 4 shown. Figure 4 In (a) of , the numerical values of the spin Hall displacement are all in units of the incident wavelength, that is

[0112] Figure 4 In (a) of

[0113] Figure 4 Figure 4 Figure 4matches the parameters of the maximum peak of the spin Hall displacement in (a). By observing the maximum peak of the spin Hall displacement for each chirality under these dual-symmetry conditions, it can be seen that chirality has a significant influence on this peak and also has a certain linear variation law. When the chirality parameter is close to 1, the peak of its spin Hall displacement can reach 2.5 wavelengths, while for nanoparticles with opposite chirality (i.e., when the chirality parameter is close to -1), this peak can only reach about one wavelength. Therefore, different chiral nanoparticles can be distinguished by comparing the magnitudes of the spin Hall displacement peaks.

[0114] Meanwhile, the spin Hall displacement is also related to the spin-orbit coupling in the near field. When stronger spin-orbit coupling appears near the particle, the corresponding peak of the spin Hall displacement is larger. The streamline of the orbital momentum density is a relatively intuitive way to observe this near-field spin-orbit interaction. After adding chirality, the streamline and intensity distribution of the orbital momentum density will also be affected accordingly, as Figure 5 shown. When circularly polarized light enters the nanoparticle, the spin angular momentum it possesses is converted into orbital angular momentum. Therefore, to a certain extent, the magnitude of the orbital momentum density and the degree of distortion of the streamline can intuitively reflect the strength of the spin-orbit coupling. It is found that for particles with larger chirality parameters, as Figure 5 shown in (c), the orbital momentum density near the particle is distributed with higher values in a larger range, and the degree of streamline distortion is greater. Conversely, for particles with opposite chirality, as Figure 5 shown in (b), the orbital momentum density value is smaller and the degree of streamline distortion is also weaker. The near-field spin-orbit coupling is reflected through the orbital momentum density, thereby further reflecting different near-field chirality information. Figure 5 (a), (b), and (c) are respectively the streamlines of the orbital momentum density and the corresponding intensity distributions near chiral nanoparticles when the chirality parameters are 0, -0.7, and 0.7 (the incident wavelengths are 1068 nm, 1081 nm, and 1081 nm respectively, that is, the wavelengths that can satisfy dual symmetry under different chirality parameters, as Figure 4 shown in (b)) Figure 5 The circles and squares in it indicate the corresponding two singularities.

[0115] As Figure 4 shown in (a), it is the optical spin Hall displacement in the wavelength range of 1050 nm to 1100 nm for different chirality parameters. It should be noted that the optical spin Hall displacement is related to the observation angle, and the curve obtained in step 102 should be the variation curve of the spin Hall displacement with respect to the scattering angle θ. However, the truly valuable information is its peak value. Therefore, in Figure 4In (a), different colors represent the peak values of the spin Hall displacement under corresponding parameters. During the actual measurement process, in this embodiment, it is not necessary to draw the spin Hall displacement curves for each set of parameters to record the corresponding maximum values. The results shown in Figure 4 can be obtained through the transfer function values calculated in step 102. The parameters satisfying dual symmetry (i.e., the parameters in the blue region in the figure) can be found, and only the spin Hall displacement curves of these parameter sets need to be drawn. In this embodiment, the chiral parameters of chiral nanoparticles can be intuitively judged from the peak values of the spin Hall displacement.

[0116] Embodiment 2

[0117] Based on the same inventive concept as Embodiment 1, this embodiment provides a system for detecting chiral parameters by applying the optical spin Hall displacement. Since the principle of solving problems by this system is similar to the method for detecting chiral parameters by applying the optical spin Hall displacement described above, the implementation of this system can refer to the implementation of the method for detecting chiral parameters by applying the optical spin Hall displacement.

[0118] As Figure 6 shown, the system for detecting chiral parameters by applying the optical spin Hall displacement includes:

[0119] An acquisition module 10, configured to acquire the permittivity, permeability, and particle radius of the chiral nanoparticles to be measured.

[0120] A first determination module 20, configured to determine the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the permittivity, permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the control mapping relationship between the optical spin Hall displacement and the chiral parameters.

[0121] An adjustment module 30, configured to adjust the incident light wavelength until quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement when circularly polarized light irradiates the chiral nanoparticles to be measured and generates the optical spin Hall effect.

[0122] A second determination module 40, configured to determine the chiral parameters of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the control mapping relationship between the optical spin Hall displacement and the chiral parameters.

[0123] Exemplarily, the first determination module includes:

[0124] A first construction unit, configured to construct the expressions of the first scattering coefficient and the second scattering coefficient :

[0125] .

[0126] where n is the first summation index; m is the second summation index; is the first expansion coefficient of the right-handed polarized light; is the second expansion coefficient of the right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying:

[0127] .

[0128] .

[0129] .

[0130] .

[0131] .

[0132] is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation; η r is the fifth intermediate variable; ; is the permittivity of the ambient medium; μ is the magnetic permeability of the ambient medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation; a is the radius of the chiral nanoparticle; k is the wave number in the ambient medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - handed polarized light; ; k2 is the wave number of the right - handed polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum; i is the imaginary unit; δ m,1 is the Kronecker symbol;

[0133] The second construction unit is used to construct the mapping relationship expression between the optical spin Hall shift Δ SH and the chirality parameter:

[0134] .

[0135] Among them, θ is the second component of the coordinate vector in the spherical coordinate system; Re(·) represents taking the real part of the numerical value; is the second scattering coefficient when m takes 1; is the associated Legendre polynomial when m takes 1; S1 is the first scattering matrix amplitude; S2 is the second scattering matrix amplitude; is the first scattering coefficient when m takes 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of the numerical value.

[0136] Exemplarily, the first determination module further includes:

[0137] A third construction unit, configured to construct an expression of the transfer function T:

[0138] .

[0139] Among them, when the quasi-dual symmetry condition is satisfied, T is 0.

[0140] For the more specific working processes of the above-mentioned respective modules, reference may be made to the corresponding content disclosed in Embodiment 1, and details will not be elaborated herein.

[0141] Embodiment 3

[0142] This embodiment provides a computer device, including a processor and a memory; among them, when the processor executes the computer program stored in the memory, the steps of the method for detecting chiral parameters by applying optical spin Hall displacement described in Embodiment 1 are implemented.

[0143] For the more specific process of the above method, reference may be made to the corresponding content disclosed in Embodiment 1, and details will not be elaborated herein.

[0144] Embodiment 4

[0145] This embodiment provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the method for detecting chiral parameters by applying optical spin Hall displacement described in Embodiment 1 are implemented.

[0146] For the more specific process of the above method, reference may be made to the corresponding content disclosed in Embodiment 1, and details will not be elaborated herein.

[0147] Embodiment 5

[0148] This embodiment provides a computer program product, including computer executable instructions or a computer program, when the computer executable instructions or the computer program are executed by a processor, the steps of the method for detecting chiral parameters by applying optical spin Hall displacement described in Embodiment 1 are implemented.

[0149] For a more specific process of the above method, reference can be made to the corresponding content disclosed in Embodiment 1, which will not be elaborated here.

[0150] The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the systems, devices, storage media, and computer program products disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0151] Those skilled in the art can clearly understand that the technologies in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solutions in the embodiments of the present invention, in essence, or the parts that contribute to the prior art can be embodied in the form of a software product. The computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0152] In some embodiments, the computer-executable instructions can be in the form of a program, software, software module, script, or code, and can be written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and can be deployed in any form, including being deployed as an independent program or being deployed as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0153] As an example, the computer-executable instructions may or may not correspond to files in the file system, and can be stored as part of a file that stores other programs or data. For example, they can be stored in one or more scripts in a Hyper Text Markup Language (HTML) document, stored in a single file dedicated to the program being discussed, or stored in multiple cooperating files (such as files that store one or more modules, subroutines, or code portions).

[0154] As an example, the computer-executable instructions can be deployed to be executed on an electronic device, or on multiple electronic devices located at one location, or on multiple electronic devices distributed at multiple locations and interconnected through a communication network.

[0155] The present invention has been described in detail above in conjunction with specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A method for detecting chiral parameters by applying the optical spin Hall shift, characterized in that Including: Obtaining the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured; Determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters; When the chiral nanoparticles to be measured are irradiated with circularly polarized light and the optical spin Hall effect is generated, adjusting the wavelength of the incident light until quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement; Determining the chiral parameter of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the mapping relationship between the optical spin Hall displacement and the chiral parameters.

2. The method for detecting chiral parameters by applying the optical spin Hall shift according to claim 1, wherein The step of determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters, includes: Construct the expressions for the first scattering coefficient and the second scattering coefficient : ； wherein, n is the first summation index; m is the second summation index; is the first expansion coefficient of the right-handed polarized light; is the second expansion coefficient of the right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying: ； ； ； ； ； is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation; η r is the fifth intermediate variable; ; is the permittivity of the environmental medium; μ is the magnetic permeability of the environmental medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation; a is the radius of the chiral nanoparticle; k is the wave number in the environmental medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - hand circularly polarized light; ; k2 is the wave number of the right - hand circularly polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum; i is the imaginary unit; δ m,1 is the Kronecker symbol; Construct the optical spin Hall displacement Δ SH Expression for the contrast mapping relationship between ； where θ is the second component of the coordinate vector in the spherical coordinate system; Re(·) represents taking the real part of a numerical value; is the second scattering coefficient when m takes 1; is the associated Legendre polynomial when m takes 1; S1 is the first scattering matrix amplitude; S2 is the second scattering matrix amplitude; is the first scattering coefficient when m takes 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of a numerical value.

3. The method for detecting chiral parameters by applying the optical spin Hall shift according to claim 2, characterized in that, The step of determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters, further includes: Constructing an expression for the transfer function T: ； Wherein, when the quasi-dual symmetry condition is satisfied, T is 0.

4. A system for detecting chiral parameters by applying the optical spin Hall shift, characterized in that, Including: An acquisition module for obtaining the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured; A first determination module for determining the optical spin Hall displacement of chiral nanoparticles with different chiral parameters under the condition of quasi-dual symmetry according to the dielectric constant, magnetic permeability, and particle radius of the chiral nanoparticles to be measured, so as to determine the mapping relationship between the optical spin Hall displacement and the chiral parameters; An adjustment module for adjusting the wavelength of the incident light until quasi-dual symmetry is satisfied to maximize the optical spin Hall displacement when the chiral nanoparticles to be measured are irradiated with circularly polarized light and the optical spin Hall effect is generated; A second determination module for determining the chiral parameter of the chiral nanoparticles to be measured at the maximum optical spin Hall displacement according to the mapping relationship between the optical spin Hall displacement and the chiral parameters.

5. The system for detecting chiral parameters by applying the optical spin Hall shift according to claim 4, wherein The first determination module includes: The first construction unit is used to construct the expressions of the first scattering coefficient and the second scattering coefficient : ； wherein, n is the first summation index; m is the second summation index; is the first expansion coefficient of the right-handed polarized light; is the second expansion coefficient of the right-handed polarized light; is the first intermediate variable; is the second intermediate variable; is the third intermediate variable; is the fourth intermediate variable, satisfying: ； ； ； ； ； is the first kind of Riccati - Bessel equation; is the third kind of Riccati - Bessel equation; is the logarithmic derivative of the first kind of Riccati - Bessel equation; η r is the fifth intermediate variable; ; is the permittivity of the environmental medium; μ is the magnetic permeability of the environmental medium; is the permittivity of the chiral nanoparticle; μ c is the magnetic permeability of the chiral nanoparticle; is the logarithmic derivative of the third kind of Riccati - Bessel equation; a is the radius of the chiral nanoparticle; k is the wave number in the environmental medium; ; ω is the angular frequency of the incident wave; k1 is the wave number of the left - hand circularly polarized light; ; k2 is the wave number of the right - hand circularly polarized light; ; κ is the chirality parameter of the chiral nanoparticle; μ0 is the magnetic permeability in vacuum; is the permittivity in vacuum; i is the imaginary unit; δ m,1 is the Kronecker symbol; A second construction unit for constructing the optical spin Hall shift Δ SH The expression of the contrast mapping relationship between ； where θ is the second component of the coordinate vector in the spherical coordinate system; Re(·) represents taking the real part of a numerical value; is the second scattering coefficient when m = 1; is the associated Legendre polynomial when m = 1; S1 is the first scattering matrix amplitude; S2 is the second scattering matrix amplitude; is the first scattering coefficient when m = 1; is the associated Legendre polynomial; (·) * represents taking the conjugate of a numerical value..

6. The system for detecting chiral parameters by applying the optical spin Hall shift according to claim 5, characterized in that, The first determination module further includes: A third construction unit for constructing an expression for the transfer function T: ； Wherein, when the quasi-dual symmetry condition is satisfied, T is 0.

7. A computer device, characterized in that, Including a processor and a memory; wherein, when the processor executes the computer program stored in the memory, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement according to any one of claims 1-3 are implemented.

8. A computer-readable storage medium, characterized in that, For storing a computer program; when the computer program is executed by a processor, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement according to any one of claims 1-3 are implemented.

9. A computer program product, characterized in that, Including computer-executable instructions or a computer program, when the computer-executable instructions or the computer program are executed by a processor, the steps of the method for detecting chiral parameters by applying the optical spin Hall displacement according to any one of claims 1-3 are implemented.

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