Systems and methods for characterizing quantum light emitter dipole structures and orientations

Abstract

The application relates to the technical field of quantum light emitter characterization, and discloses a quantum light emitter dipole structure and orientation characterization system and method.The characterization system comprises a quantum light emitter sample fixing assembly, a fluorescence excitation, fluorescence detection and fluorescence lifetime measurement assembly, a scanning near-field optical probe assembly, a scanning near-field optical probe control assembly and a data processing module.The scanning near-field optical probe assembly performs three-dimensional space scanning around a quantum light emitter to be measured, obtains a Purcell factor distribution, and compares the Purcell factor distribution with a Purcell factor distribution obtained by numerical simulation under any dipole structure and orientation parameter, so as to fit the three-dimensional dipole structure and orientation parameter of the quantum light emitter to be measured.The characterization scheme provided by the application is a near-field characterization scheme based on fluorescence lifetime information, has better robustness and higher resolution compared with a traditional far-field characterization scheme based on fluorescence intensity information, and can more accurately characterize the three-dimensional dipole parameter of the quantum light emitter.

Description

Technical Field

[0001] This invention relates to the field of quantum light emitter characterization technology, and specifically discloses a system and method for characterizing the dipole structure and orientation of quantum light emitters using scanning near-field fluorescence lifetime imaging technology. Background Technology

[0002] Quantum light emitters have a wide range of applications. For example, efficient coupling of quantum light emitters with micro / nano optical structures can realize high-quality on-chip integrated quantum light sources; quantum light emitters can be used as fluorescent markers for fluorescence imaging; and the coupling between multiple quantum light emitters can realize quantum computing and simulation. These applications all involve obtaining information about the dipole structure of quantum light emitters and manipulating their orientation. Therefore, accurate characterization of the dipole structure and orientation of quantum light emitters is of great significance.

[0003] Generally, the dipole structure and orientation of a room-temperature quantum light emitter can be described by a three-dimensional dipole model. This three-dimensional dipole model consists of an incoherent superposition of three mutually perpendicular linear dipoles d1, d2, and d3. When only the relative magnitudes of the dipole moments are considered, five independent parameters (α, β, θ1, φ1, φ2, φ3) are required. rot To describe the three-dimensional dipole model, where and This represents the relative proportions between three linear dipoles d1, d2, and d3. θ1 and φ1 represent the orientations of dipole d1 and φ1, respectively. rot This represents the angle of rotation of d2 in a plane perpendicular to d1.

[0004] Currently, characterization methods for the dipole structure and orientation of quantum light emitters mainly include fluorescence polarization analysis, fluorescence defocus imaging fitting, and fluorescence back focal plane imaging fitting. These methods are all based on the far-field radiation information of the quantum light emitter's fluorescence, and have the following drawbacks: far-field information is easily affected by the surrounding environment of the quantum light emitter; for example, the substrate may alter the far-field characteristics. During the transmission of fluorescence information to the far field, it is also easily affected by the optical path and experimental setup, causing distortion of the final far-field information. Simultaneously, the imaging accuracy of the camera greatly limits the image quality. These factors make it difficult to accurately fit the three-dimensional dipole model of the quantum light emitter using far-field radiation information. Therefore, in practical measurements, it is often necessary to simplify the three-dimensional dipole model of the quantum light emitter, using a simpler two-dimensional or one-dimensional dipole model, which leads to an inaccurate description of the dipole structure. With the continuous deepening of research and the rapid development of quantum light emitter-related applications, accurately understanding the dipole structure and orientation of quantum light emitters is becoming increasingly important. Therefore, there is an urgent need to develop a characterization system and method that can accurately characterize the three-dimensional dipole structure and orientation of quantum light emitters. Summary of the Invention

[0005] The technical problem of this invention is to provide a system and method that can accurately characterize the three-dimensional dipole structure and orientation of quantum light emitters.

[0006] To address the above problems, this invention first provides a characterization system for the dipole structure and orientation of a quantum light emitter, comprising:

[0007] A quantum light emitter sample fixing assembly is used to fix the quantum light emitter sample to be measured.

[0008] A fluorescence excitation, fluorescence detection, and fluorescence lifetime measurement component is used to excite the quantum light emitter under test, detect the fluorescence of the quantum light emitter, and analyze the fluorescence lifetime of the quantum light emitter.

[0009] A scanning near-field optical probe assembly is used to perform three-dimensional spatial scanning around the analyte emitting element. By using the Purcell effect to change the fluorescence lifetime of the analyte emitting element, the fluorescence lifetime at each scanning spatial location is recorded to obtain the fluorescence lifetime distribution.

[0010] A scanning near-field optical probe control assembly is used to control the scanning near-field optical probe assembly to move in three-dimensional space around the luminescent sample to be measured;

[0011] The data processing module performs the following functions: it processes the fluorescence lifetime distribution data obtained from the experiment to obtain the Purcell factor distribution; it performs numerical simulation to simulate the Purcell factor distribution when the quanta emitter has an arbitrary dipole structure and orientation parameters; and it determines the dipole structure and orientation parameters through fitting so that the Purcell factor distribution simulated by numerical simulation best matches the Purcell factor distribution measured in the experiment.

[0012] Optionally, the scanning near-field optical probe assembly includes a dielectric nanoneedle tip and a metal nanostructure located on the tip surface of the dielectric nanoneedle tip.

[0013] Optionally, the dielectric nanoneedle tip is a tapered fiber tip or an atomic force microscope probe.

[0014] Optionally, the end face diameter of the tapered fiber tip is 50 to 500 nanometers.

[0015] Optionally, the metal nanostructure located on the tip surface of the dielectric nanoneedle is a metal nanoparticle, which is loaded onto the tip surface of the dielectric nanoneedle by a chemical adhesive.

[0016] Optionally, the metal nanoparticles are spherical gold nanoparticles.

[0017] Optionally, the spherical gold nanoparticles have a radius of 20 to 50 nanometers.

[0018] Optionally, the quantum light emitter sample immobilization assembly includes a transparent substrate and silica nanospheres, wherein the silica nanospheres are immobilized on the surface of the transparent substrate, and the quantum light emitter to be measured is encapsulated within the silica nanospheres.

[0019] Optionally, the radius of the silica nanospheres is 10 to 30 nanometers.

[0020] Optionally, the silica nanospheres are fixed to the surface of a transparent substrate by an organic polymer film, the thickness of which is 4 to 8 nanometers.

[0021] This invention also provides a method for characterizing the dipole structure and orientation of quantum light emitters based on the above-mentioned characterization system, comprising the following steps:

[0022] The quantum light emitter sample fixing assembly is used to fix the quantum light emitter to be measured.

[0023] The fluorescence excitation, fluorescence detection and fluorescence lifetime measurement components are used to excite the quantum light emitter under test, detect the fluorescence of the quantum light emitter and analyze the fluorescence lifetime of the quantum light emitter.

[0024] The scanning near-field optical probe control component controls the scanning near-field optical probe component to perform three-dimensional spatial scanning around the quantum luminescent body to be measured; the scanning near-field optical probe component causes the fluorescence lifetime of the quantum luminescent body to be measured to change through the Purcell effect, and records the fluorescence lifetime of the quantum luminescent body at each scanning spatial position point to obtain the fluorescence lifetime distribution.

[0025] The experimental data is processed using the data processing module to obtain the Purcell factor distribution; the Purcell factor distribution of the quanta is simulated using numerical simulation with arbitrary dipole structure and orientation parameters; the dipole structure and orientation parameters are determined by fitting using the data processing module so that the Purcell factor distribution simulated by numerical simulation best matches the Purcell factor distribution measured experimentally, thus obtaining the three-dimensional dipole structure and orientation of the quanta.

[0026] Optionally, the quantum light emitter sample fixing assembly fixes the quantum light emitter to be measured in the following manner: the quantum light emitter sample fixing assembly includes a transparent substrate and silica nanospheres, the quantum light emitter to be measured is covered in the center of the silica nanospheres, and the silica nanospheres are fixed on the surface of the transparent substrate by an organic polymer film.

[0027] Preferably, the scanning near-field optical probe assembly performs a three-dimensional spatial scan around the quanta to be measured, wherein the scanning near-field optical probe assembly includes a dielectric nanoneedle tip and a spherical gold nanoparticle located on the tip surface of the dielectric nanoneedle tip. The quanta to be measured is encapsulated in the center of a silica nanosphere. When the scanning near-field optical probe assembly performs a three-dimensional spatial scan around the quanta to be measured, the spherical gold nanoparticle runs closely to the surface of the silica nanosphere.

[0028] Compared with the prior art, the present invention has the following main advantages:

[0029] 1. This invention uses the fluorescence lifetime variation information of quantum light emitters to characterize the dipole structure and orientation of quantum light emitters. Compared with the traditional method that uses fluorescence intensity distribution information, it has better robustness and is not affected by factors such as optical path, experimental device and camera resolution.

[0030] 2. The near-field scanning characterization method proposed in this invention is based on near-field information, is not affected by the optical diffraction limit, and has higher resolution.

[0031] 3. This invention does not require prior knowledge of the dipole model of the luminescent sample to be measured, but directly uses a universal three-dimensional dipole model for description, thus it is applicable to the accurate characterization of various dipole structures. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a specific quantum light emitter dipole structure and orientation characterization system according to the present invention. In the figure: 1 is a spherical gold nanoparticle; 2 is a silica nanosphere; 3 is the quantum light emitter to be measured coated in silica nanospheres; 4 is an organic polymer film; 5 is a transparent substrate; 6 is a tapered optical fiber; 7 is a quartz tuning fork; 8 is a preamplifier; 9 is an inverted microscope; 10 is a dichroic mirror; 11 is the input laser; 12 is the fluorescence of the quantum light emitter collected by the inverted microscope; 13 is a mirror; 14 is a pulsed laser; 15 is a single-photon detector; 16 is a time-correlated single-photon counter; 17 is the synchronization signal input channel of the time-correlated single-photon counter; 18 is the photon signal input channel of the time-correlated single-photon counter.

[0033] Figure 2 This is a schematic diagram illustrating a method for adhering a gold nanoparticle to the end face of a tapered optical fiber. Figure 2 (a) indicates that the tapered fiber probe was positioned directly above a target gold nanoparticle before the probe was lowered. Figure 2 (b) indicates that the tapered fiber probe is in contact with the target gold nanoparticle. Figure 2 (c) indicates that the tapered fiber probe is raised, at which point the target gold nanoparticles have been adsorbed onto the probe end face.

[0034] Figure 3 This is a scanning electron microscope image of a tapered fiber optic probe that has adsorbed a spherical gold nanoparticle.

[0035] Figure 4 This is a transmission electron microscope (TEM) image of a quantum dot sample encapsulated in silica spheres.

[0036] Figure 5 This is a schematic diagram of scanning a quantum light-emitting sample using a scanning near-field optical probe. In the diagram: 19 is a laser beam incident at a total internal reflection angle; 20 is the scanning trajectory.

[0037] Figure 6 This is a distribution diagram of the raw experimental measurement data for a quantum dot sample, where... Figure 6 (a) is a distribution diagram of probe height z(x,y); Figure 6 (b) is the distribution plot of Purcell factor F(x,y).

[0038] Figure 7 A schematic diagram of the scanning trajectory at the center of the spherical gold nanoparticle: Figure 7 (a) illustrates the relationship between scanning trajectory parameters and parameters such as the radius of spherical gold nanoparticles, the radius of silica nanospheres, and the thickness of polymer films. Figure 7 (b) is the ideal scanning trajectory diagram of the center of the spherical gold nanoparticle. In the figure, 21 is the planar part of the scanning trajectory diagram and 22 is the spherical part of the scanning trajectory diagram.

[0039] Figure 8 The Purcell factor distribution, as measured experimentally, is plotted on a sphere.

[0040] Figure 9 This is a three-dimensional dipole model of quantum dots fitted based on the experimentally measured Purcell factor distribution.

[0041] Figure 10 To plot the measured Purcell factor distribution on a three-dimensional surface: Figure 10 (a) is the distribution of Purcell factor obtained from the experiment; Figure 10 (b) is the Purcell factor distribution obtained by simulation based on the fitted three-dimensional dipole model. Detailed Implementation

[0042] To better understand, embodiments of the invention will now be described by way of non-limiting examples with reference to the accompanying drawings. It should be noted that those skilled in the art will understand that reasonable modifications to the systems and methods of the invention still fall within the scope of protection of the invention. It should also be noted that the optical elements in the drawings are not intended to be scaled-down.

[0043] Combination Figure 1The diagram illustrates a specific quantum light emitter radiative dipole structure and orientation characterization system, comprising a quantum light emitter sample fixation assembly, a fluorescence excitation, fluorescence detection, and fluorescence lifetime measurement assembly, a scanning near-field optical probe assembly, a scanning near-field optical probe control assembly, and a data processing module. Among these components...

[0044] The quantum luminescent sample immobilization assembly includes silica nanospheres 2. The quantum luminescent sample 3 to be measured is encapsulated within the silica nanospheres 2 and immobilized on a transparent substrate 5 by an organic polymer film 4. The silica nanospheres have a radius of 10 to 30 nanometers, and the organic polymer film has a thickness of 4 to 8 nanometers. Ideally, the quantum luminescent sample 3 to be measured is encapsulated at the center of the silica nanospheres 2.

[0045] A fluorescence excitation, fluorescence detection, and fluorescence lifetime measurement assembly includes a pulsed laser, an inverted optical microscope, a single-photon detector, and a time-correlated single-photon counter. The pulsed laser emits laser pulses to excite the quantum luminescent sample and generates a synchronous electronic pulse signal to the time-correlated single-photon counter. The inverted optical microscope guides the laser emitted by the pulsed laser to the quantum luminescent sample to excite fluorescence, collects the emitted fluorescence, and transmits it to the single-photon detector for detection. The single-photon detector detects the fluorescence photons emitted by the quantum luminescent sample, generating an electrical pulse signal upon detection and sending it to the time-correlated single-photon counter. The time-correlated single-photon counter receives the synchronous electronic pulse signal from the pulsed laser and the electrical pulse signal from the single-photon detector, analyzes the time difference of the pulse signals, and thus obtains the fluorescence lifetime of the quantum luminescent sample. Figure 1 As shown, the pulsed laser 11 emitted by the pulsed laser 14 is reflected by the dichroic mirror 10 and focused onto the sample 3 on the transparent substrate 5 by the inverted microscope objective 9. The fluorescence emitted by the quantum light-emitting sample is collected by the inverted microscope objective 9, passes through the dichroic mirror 10, and is reflected by the mirror 13. It is then detected by the single-photon detector 15. The single-photon detection electrical pulse signal of the single-photon detector 15 is connected to the photon signal input channel 18 of the time-correlated single-photon counter 16, and the synchronization electrical pulse signal of the pulsed laser 14 is connected to the synchronization signal input channel 17 of the time-correlated single-photon counter 16. The fluorescence lifetime of the quantum light-emitting sample is obtained by statistical analysis of the pulse arrival time difference between the photon signal channel 18 and the synchronization signal channel 17.

[0046] The scanning near-field optical probe assembly consists of a tapered optical fiber 6 with a tip diameter of 50 to 500 nanometers and a spherical gold nanoparticle 1 with a radius of 20 to 50 nanometers located on its end face. Those skilled in the art will recognize that the tapered optical fiber 6 can also be replaced by an atomic force microscope probe.

[0047] The scanning near-field optical probe control assembly includes a piezoelectric ceramic tube (not shown), a piezoelectric ceramic tube controller (not shown), a quartz tuning fork 7, a tuning fork welding circuit board (not shown), a preamplifier circuit board (not shown), a tuning fork control system (not shown), and a feedback control system (not shown). The tapered fiber optic probe 6 of the scanning near-field optical probe assembly is attached to a quartz tuning fork 7 with a resonant frequency of 40kHz. The quartz tuning fork is welded to the tuning fork welding circuit board, which is fixed to the preamplifier circuit board with screws. The preamplifier circuit board is connected to the tuning fork control system by wires and is fixed to one end of the piezoelectric ceramic tube. The piezoelectric ceramic tube controller controls the movement of the piezoelectric ceramic tube in three dimensions, enabling the scanning near-field optical probe to perform three-dimensional scanning. During the scanning process, the interaction between the scanning near-field optical probe and the physical surface causes a change in the amplitude of the quartz tuning fork. The amplitude change signal of the quartz tuning fork is fed back to the piezoelectric ceramic tube controller through the feedback control system, maintaining a constant distance between the scanning near-field optical probe and the physical surface.

[0048] A specific fabrication method for scanning near-field optical probe components is as follows: Figure 2 As shown: A spherical gold nanoparticle colloidal solution was spin-coated onto the surface of a transparent substrate to form a single-particle dispersed spherical gold nanoparticle sample. The radius R of the spherical gold nanoparticles is... AuNS The nanometers are 20 to 50 nanometers; then, a tapered fiber probe 6, soaked in a poly-L-lysine solution, is moved directly above one of the target gold nanoparticles 1, as illustrated. Figure 2 As shown in (a); then the probe is lowered to contact the target gold nanoparticle 1, as shown in (a). Figure 2 As shown in (b); then the probe is lifted, and the gold nanoparticles 1 can be adsorbed onto the end face of the tapered fiber probe, as shown in (b). Figure 2 As shown in (c). Figure 3 A scanning electron microscope image of a tapered fiber optic probe adsorbed with a spherical gold nanoparticle is shown.

[0049] In this embodiment, the quantum luminescent sample to be measured is colloidal quantum dots. First, the colloidal quantum dots are coated into silica nanospheres. A specific method for coating colloidal quantum dots into silica nanospheres is as follows: First, prepare a reaction vessel and add 1 mL of a 3 mM tetraethyl orthosilicate ethanol solution; then, under vigorous stirring, continue adding 110 μL of an 80 nM quantum dot colloidal aqueous solution to the reaction vessel; immediately afterward, inject 5 μL of a 0.1 M sodium hydroxide aqueous solution as a catalyst for the hydrolysis reaction of tetraethyl orthosilicate, initiating the silica coating process; finally, under room temperature and light-protected conditions, continuously and vigorously stir the reaction mixture for 24 hours to obtain a colloidal solution of quantum dots coated into silica nanospheres. Figure 4 This is a transmission electron microscopy (TEM) image of quantum dots encapsulated in silica nanospheres. The colloidal solution of quantum dots encapsulated in silica nanospheres was diluted and spin-coated onto a transparent substrate, thus forming a monodisperse quantum dot sample encapsulated in silica nanospheres on the substrate. Next, a certain mass fraction of an organic polymer solution (e.g., a toluene solution from Zeonex) was spin-coated onto the substrate to form an organic polymer film that immobilizes the quantum dot sample.

[0050] Scanning near-field fluorescence lifetime imaging of quantum dot samples was performed using a scanning near-field optical probe assembly. For example... Figure 5 As shown, laser 19 is obliquely incident at a total internal reflection angle to excite the quantum dot sample. When the scanning near-field optical probe performs spatial scanning, the spherical gold nanoparticles on the probe are always closely attached to the sample surface. Where there are no silica nanospheres, they are closely attached to the surface of the organic polymer film, and where there are silica nanospheres, they are closely attached to the surface of the silica nanospheres. That is, they move according to the scanning trajectory indicated by the dashed line 20. The fluorescence lifetime of the quantum dot to be measured changes through the Purcell effect. During the scanning process, the height information z(x,y) of the probe and the fluorescence lifetime information τ(x,y) of the quantum dot obtained by the fluorescence lifetime measurement component are recorded, where (x,y) is the planar coordinate position of the probe. Figure 6 (a) shows the experimentally measured probe height distribution z(x,y). Figure 6 (b) is the experimentally measured fluorescence lifetime shortening factor F(x,y)=τ0 / τ(x,y), which is also the distribution of the Purcell factor, where the baseline fluorescence lifetime τ0 is the fluorescence lifetime of the quantum dot when it is far away from the gold nanoparticle.

[0051] Then, the data processing module is used to process the data, thereby determining the three-dimensional dipole structure and orientation of the quanta to be measured, that is, determining the three-dimensional dipole model parameters (α,β,θ1,φ1,φ). rot Data processing included: processing the experimental data to obtain the relationship between the Purcell factor and the orientation of the spherical gold nanoparticles, F(θ,φ); and performing numerical simulations to obtain the parameters (α,β,θ1,φ1,n) of the arbitrary dipole model. rot The relationship between Purcell factor and orientation of spherical gold nanoparticles (F) 仿真 (θ,φ); find the fit that makes F 仿真 (θ,φ) The three-dimensional dipole model parameters (α,β,θ1,φ1,φ) closest to F(θ,φ) rot This involves determining the three-dimensional dipole structure and orientation of the luminescent material to be measured. The specific data processing steps are as follows:

[0052] according to Figure 6(a) The centroid of the height distribution can be used to obtain the coordinate position (x0, y0) corresponding to the center of the silica nanosphere. According to Figure 6 The maximum height of (a) allows us to determine the height difference ΔH between the top of the silica nanospheres and the surface of the organic polymer film. The thickness H of the organic polymer film... film The radius of the silica nanospheres was determined by atomic force microscopy after scrubbing the thin film with a metal needle tip.

[0053] like Figure 7 (a) shows a schematic diagram of the scanning trajectory of the spherical gold nanoparticles. During scanning, the scanning trajectory of the portion of the spherical gold nanoparticles that is in close contact with the surface of the polymer film is planar. Figure 7 As shown in plane 21 in (b), the trajectory of the spherical gold nanoparticles adhering to the silica surface has a radius of... A portion of the sphere, such as Figure 7 As shown in sphere 22 in (b), the half-angle θ subtended by sphere 22 max =arccos(H tri / R scan ),in The projection of sphere 22 onto the xy plane is a circle with center (x0, y0) and radius R. contact =

[0054] R scan sinθ max ,like Figure 6 (a) and Figure 6 (b) shows the circular region bounded by the dashed circle. The position coordinates (x, y) within this circular region can be mapped one-to-one to the azimuth coordinates (θ, φ) on sphere 22. Therefore, Figure 6 (b) The data F(x,y) within the dashed circle (i.e., the data obtained by scanning the spherical gold nanoparticles in close contact with the silica nanospheres) can be plotted on the sphere 22, thus obtaining F(θ,φ), as shown below. Figure 8 As shown. F(θ,φ) will be compared with the numerical simulation result F 仿真 Compare (θ,φ) and find the fit that makes F 仿真 (θ,φ) The three-dimensional dipole model parameters (α,β,θ1,φ1,φ) that best approximate the experimental data F(θ,φ) rot This set of parameters represents the measurement results of the dipole structure and orientation parameters of the sample to be measured. Figure 8 The F(θ,φ) data shown is fitted to obtain the three-dimensional dipole model parameters as (α,β,θ1,φ1,φ). rot The three-dimensional dipole model diagram corresponding to (0.79, 0.36, 67, 319°, 97°) is shown below. Figure 9 As shown.

[0055] The above parameter fitting requires efficient acquisition of arbitrary dipole model parameters (α,β,θ1,φ1,φ). rot F under ) 仿真 (θ,φ), the specific method is as follows. The unit dipole p is simulated and calculated when spherical gold nanoparticles are closely attached to silica nanospheres and located at orientation (θ,φ). x ,p y ,p z Excite the electric field at the lower dipole Thus, the dyadic Green's tensor at that position is obtained.

[0056]

[0057] Where ω0 is the frequency of the dipole, and μ is the permeability at the location of the dipole. Simulations are performed to calculate the unit dipole p in the absence of spherical gold nanoparticles. x ,p y ,p z Excite the electric field at the lower dipole Thus, the dyadic Green's tensor at that position is obtained.

[0058]

[0059] For an arbitrary parameter (α,β,θ1,φ1,φ), rot ) three-dimensional dipole d 3D It consists of an incoherent superposition of three mutually perpendicular linear dipoles d1, d2, and d3, and its Purcell factor can be expressed as F. 仿真 in When spherical gold nanoparticles are closely attached to silica nanospheres and located at orientation (θ, φ), s i Projection of local photon density of states in the direction, When spherical gold nanoparticles are absent, d i Projection of local photon density of states in the direction.

[0060] To make the Purcell factor distribution plot more intuitive, the Purcell factor distribution is plotted on a surface, and the magnitude of the Purcell factor is expressed by both color and the distance from a point on the surface to the center: Figure 10 (a) shows the experimentally measured distribution of the Purcell factor; Figure 10 (b) shows the Purcell factor distribution obtained from the simulation based on the fitted three-dimensional dipole model. It can be seen that the shape of the experimentally measured Purcell factor distribution is very similar to the shape of the simulated Purcell factor distribution. This indicates that the fitting results can accurately describe the radiative dipole model and orientation of the quantum dot.

[0061] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A characterization system for the dipole structure and orientation of a quantum light emitter, characterized in that, include: A quantum light emitter sample fixing assembly is used to fix the quantum light emitter sample to be measured. A fluorescence excitation, fluorescence detection, and fluorescence lifetime measurement component is used to excite the quantum light emitter under test, detect the fluorescence of the quantum light emitter, and analyze the fluorescence lifetime of the quantum light emitter. A scanning near-field optical probe assembly is used to perform three-dimensional spatial scanning around a quantum light emitter. The fluorescence lifetime of the quantum light emitter changes due to the Purcell effect, and the fluorescence lifetime at each scanning spatial location is recorded to obtain the fluorescence lifetime distribution. The scanning near-field optical probe assembly includes a dielectric nanoneedle tip and a metal nanostructure located on the tip surface of the dielectric nanoneedle. The metal nanostructure located on the tip surface of the dielectric nanoneedle is a spherical metal nanoparticle, which is loaded onto the tip surface of the dielectric nanoneedle using a chemical adhesive. A scanning near-field optical probe control assembly is used to control the scanning near-field optical probe assembly to move in three-dimensional space around the luminescent sample to be measured; The data processing module performs the following functions: processing the fluorescence lifetime distribution data obtained from the experiment to obtain the Purcell factor distribution; and numerically simulating the Purcell factor distribution when the analyte emitter has an arbitrary dipole structure and orientation parameters. By fitting the dipole structure and orientation parameters, the Purcell factor distribution simulated by numerical simulation is determined to best match the Purcell factor distribution measured experimentally.

2. The characterization system for the dipole structure and orientation of a quantum light emitter according to claim 1, characterized in that, The medium nanoneedle tip is a tapered fiber optic tip or an atomic force microscope probe.

3. The characterization system for the dipole structure and orientation of a quantum light emitter according to claim 2, characterized in that, The tip diameter of the tapered optical fiber is 50 to 500 nanometers.

4. The characterization system for the dipole structure and orientation of a quantum light emitter according to claim 1, characterized in that, The quantum light emitter sample immobilization assembly includes a transparent substrate and silica nanospheres. The silica nanospheres are fixed on the surface of the transparent substrate, and the quantum light emitter to be measured is encapsulated within the silica nanospheres. The silica nanospheres have a radius of 10 to 30 nanometers.

5. The characterization system for the dipole structure and orientation of a quantum light emitter according to claim 4, characterized in that, The silica nanospheres are fixed on the surface of the transparent substrate by an organic polymer film with a thickness of 4 to 8 nanometers.

6. A method for characterizing the quantum light-emitting diode dipole structure and orientation based on the characterization system described in claim 1, characterized in that, Includes the following steps: The quantum light emitter sample fixing assembly is used to fix the quantum light emitter to be measured. The fluorescence excitation, fluorescence detection and fluorescence lifetime measurement components are used to excite the quantum light emitter under test, detect the fluorescence of the quantum light emitter and analyze the fluorescence lifetime of the quantum light emitter. The scanning near-field optical probe control component controls the scanning near-field optical probe component to perform three-dimensional spatial scanning around the quanta to be measured; the scanning near-field optical probe component causes the fluorescence lifetime of the quanta to change through the Purcell effect, records the fluorescence lifetime corresponding to each scanning spatial position point, and obtains the fluorescence lifetime distribution. The experimental data is processed using the data processing module to obtain the Purcell factor distribution; the Purcell factor distribution of the quanta is simulated using numerical simulation with arbitrary dipole structure and orientation parameters; the dipole structure and orientation parameters are determined by fitting using the data processing module so that the Purcell factor distribution simulated by numerical simulation best matches the Purcell factor distribution measured experimentally, thus obtaining the three-dimensional dipole structure and orientation of the quanta.

7. The method for characterizing the dipole structure and orientation of a quantum light emitter according to claim 6, characterized in that, The quantum light emitter sample fixing assembly fixes the quantum light emitter to be measured in the following manner: the quantum light emitter sample fixing assembly includes a transparent substrate and silica nanospheres, the quantum light emitter to be measured is covered in the center of the silica nanospheres, and the silica nanospheres are fixed on the surface of the transparent substrate by an organic polymer film.

8. The method for characterizing the dipole structure and orientation of a quantum light emitter according to claim 6, characterized in that, The scanning near-field optical probe assembly performs a three-dimensional spatial scan around the quanta to be measured. The scanning near-field optical probe assembly includes a dielectric nanoneedle tip and a spherical gold nanoparticle located on the tip surface of the dielectric nanoneedle tip. The quanta to be measured is encapsulated in the center of a silica nanosphere. When the scanning near-field optical probe assembly performs a three-dimensional spatial scan around the quanta to be measured, the spherical gold nanoparticle runs closely to the surface of the silica nanosphere.

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