Airy beam and Gaussian beam superposed scanning structured light microscopic imaging system and method

Abstract

The invention relates to the technical field of optical microscopic imaging, and discloses a scanning structured light microscopic imaging system and a scanning structured light microscopic imaging method of Airy beam and Gaussian beam superposed, and the Gaussian beam emitted by a laser light source sequentially passes through an electro-optical modulator and a lens group and is incident to a spatial light modulator loaded with an Airy beam mask plate; the spatial light modulator is used for modulating an incident Gaussian beam by adopting zero-order light to form exciting light formed by superposing an Airy beam and the Gaussian beam; exciting light sequentially passes through the 4F system, the X-Y scanning galvanometer, the scanning lens, the tube lens, the emission optical filter, the double-color piece and the objective lens and then irradiates a sample to be imaged; fluorescent light generated by a to-be-imaged sample passes through the objective lens and the double-color piece and then is transmitted to the photomultiplier tube for fluorescent light image acquisition. According to the invention, a light beam scheme of overlapping the Airy beam and the Gaussian beam is adopted, and the Gaussian beam is utilized to suppress the side lobe effect of the Airy beam, so that artifacts in Airy beam imaging are effectively removed, and the imaging resolution is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical microscopic imaging, and in particular to a scanning structured light microscopic imaging system and method of an Airy beam superimposed on a Gaussian beam. Background Art

[0002] In 1979, Berry and Balazs theoretically predicted the existence of Airy beams, which are light waves that can propagate without diffraction in free space and move along a curved path, similar to the shape of a parabola. However, the ideal Airy beam has infinite energy and cannot be observed in practice. It was not until 2007 that a research team at the University of Central Florida in the United States observed a finite-energy Airy beam for the first time through experiments, which attracted widespread attention in the scientific community and started a wave of further research on Airy beams.

[0003] Due to its self-acceleration and non-diffraction properties, the non-diffracting Airy beam exhibits unique advantages and can maintain beam focus over a long distance. This feature enables the Airy beam to map axial extension information onto a two-dimensional image, thereby significantly improving the data acquisition speed, and expanding the axial imaging range by lengthening the focus to achieve fast volume acquisition. These novel properties of the Airy beam have promoted its wide application in many fields, such as light sheet fluorescence microscopy, plasma channel regulation, and particle manipulation. In addition, in three-dimensional super-resolution microscopy, the non-diffracting propagation of the Airy beam is used to accurately locate molecules along the axial direction, further expanding its application potential in biological imaging. Although the Airy beam has advantages in fast volume imaging, the sidelobe structure in the Airy beam will introduce artifacts and lead to a loss of resolution. The generation of sidelobes originates from the mathematical construction and physical properties of the Airy beam. The light field distribution of the Airy beam is described by the Airy function, which is an inhomogeneous oscillation function. There will be a series of decaying oscillations outside the core area of ​​the main beam, namely the sidelobes. This oscillation is an inherent characteristic of the Airy beam, which causes the light field to form multiple secondary extreme points outside the main peak, thus forming a sidelobe structure. These side lobes do not decay rapidly with propagation distance like ordinary Gaussian beams, but remain relatively stable over a long distance, which is part of the reason why Airy beams can achieve long-distance diffraction-free propagation. Although the existence of side lobes gives Airy beams unique self-healing capabilities and spatial distribution characteristics, in imaging applications, these side lobes may interfere with the main beam signal, thereby introducing artifacts and affecting the resolution and contrast of imaging.

[0004] Therefore, how to overcome the problem of insufficient resolution caused by the side lobes of the Airy beam in the prior art has become an important research topic in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a scanning structured light microscopy imaging system and method of an Airy beam superimposed on a Gaussian beam, which adopts a beam scheme in which the Airy beam and the Gaussian beam are superimposed, and uses the Gaussian beam to suppress the sidelobe effect of the Airy beam, thereby effectively removing artifacts in Airy beam imaging and improving imaging resolution, so as to overcome the problem of insufficient resolution caused by the sidelobe of the Airy beam in the prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] On the one hand, the present invention provides a scanning structured light microscopic imaging system of Airy beam superimposed Gaussian beam, the system comprising: a laser light source, an electro-optical modulator, a lens group, a spatial light modulator, a 4F system, an XY scanning galvanometer, a scanning lens, a tube lens, an emission filter, a dichroic film, an objective lens, and a photomultiplier tube arranged in sequence along an excitation light path;

[0008] The laser light source is used to emit a Gaussian beam; the Gaussian beam emitted by the laser light source passes through an electro-optic modulator and a lens group in sequence and is incident on a spatial light modulator, the spatial light modulator is loaded with an Airy beam mask, and the incident Gaussian beam is modulated with zero-order light to form an excitation light in which the Airy beam and the Gaussian beam are superimposed;

[0009] The excitation light of the superposition of the Airy beam and the Gaussian beam passes through the 4F system, XY scanning galvanometer, scanning lens, tube lens, emission filter, dichroic filter, and objective lens in sequence, and then irradiates the sample to be imaged. The excitation light interacts with the fluorescent marker in the sample to be imaged, and excites the sample to be imaged to produce fluorescence;

[0010] The fluorescence generated by the sample to be imaged passes through the objective lens and the dichroic film, and is then transmitted to the photomultiplier tube for fluorescence image acquisition.

[0011] Furthermore, the light intensity signal I of the excitation light superimposed by the Airy beam and the Gaussian beam is total (x,y,z), the formula is as follows:

[0012]

[0013] Among them, R e represents the real part, It reflects the mutual interference effect between the two beams; E Airy (x, y, z) represents the electric field strength of the Airy beam, E Gaussian (x, y, z) represents the electric field intensity of the Gaussian beam, and * represents the complex conjugate;

[0014] I Gaussian (x, y, z) represents the intensity of the Gaussian beam, and the formula is as follows:

[0015] IGaussian (x,y,z)=|E Gaussian (x,y,z)| 2 (7)

[0016] I Airy (x,y,z) represents the intensity of the Airy beam,

[0017] I Airy (x,y,z)=|E Airy (x,y,z)| 2 (8)

[0018] When z = 0, the intensity ratio R between the Airy beam and the Gaussian beam is quantified. a , by calculating the integral of the intensity of the Airy beam and the Gaussian beam over the entire beam area, and then determining the ratio:

[0019]

[0020] The ratio R a A quantitative assessment of the relative intensity contributions of Airy and Gaussian beams over the entire beam area is provided.

[0021] Furthermore, a first half-wave plate is arranged between the laser light source and the electro-optical modulator, and the first half-wave plate is used to adjust the polarization state of the Gaussian light beam; a first reflector is also arranged between the electro-optical modulator and the lens group, and the Gaussian light beam adjusted by the electro-optical modulator is reflected to the lens group through the first reflector.

[0022] Furthermore, the lens group includes a first lens and a second lens, the radius of the first lens is smaller than the radius of the second lens, and the Gaussian light beam incident on the lens group passes through the first lens and the second lens in sequence to be magnified and collimated.

[0023] Furthermore, a second half-wave plate is arranged between the lens group and the spatial light modulator, and the second half-wave plate is used to adjust the polarization direction of the Gaussian light beam emitted through the lens group so that the polarization direction of the Gaussian light beam is parallel to the liquid crystal surface of the spatial light modulator.

[0024] Furthermore, the 4F system includes a third lens and a fourth lens, the radius of the third lens is larger than the radius of the fourth lens, and the 4F system is used to reduce the size and collimate the excitation light that is a superposition of the Airy beam and the Gaussian beam, so that the beam size of the excitation light is the same as the size of the Gaussian beam before passing through the lens group.

[0025] Furthermore, a second reflector is provided between the 4F system and the XY scanning galvanometer, and the second reflector is used to change the optical path direction of the excitation light emitted through the 4F system so that the optical path direction of the excitation light is spatially conjugate with the XY scanning galvanometer.

[0026] Furthermore, a bandpass filter and a converging lens are provided between the dichroic filter and the photomultiplier tube. The fluorescent signal emitted by the dichroic filter is focused to the photomultiplier tube through the converging lens after stray light is filtered out by the bandpass filter.

[0027] Furthermore, the system also includes a computer, which is electrically connected to the electro-optic modulator, spatial light modulator, XY scanning galvanometer and photomultiplier tube respectively; the computer is used to control the electro-optic modulator to modulate the Gaussian light beam into a modulated light beam whose light intensity changes periodically over time according to a sine function, and is also used to control the spatial light modulator to generate excitation light that is a superposition of the Airy beam and the Gaussian beam, and is also used to control the XY scanning galvanometer to sequentially scan the excitation light spots focused with different intensities point by point to the sample to be imaged, and is also used to obtain a fluorescence image of the sample to be imaged through the photomultiplier tube.

[0028] On the other hand, the present invention further provides a scanning structured light microscopy imaging method of an Airy beam superimposed on a Gaussian beam, which is applied to the above-mentioned scanning structured light microscopy imaging system of an Airy beam superimposed on a Gaussian beam, and comprises the following steps:

[0029] The laser source emits a Gaussian beam;

[0030] The Gaussian beam is modulated by an electro-optic modulator and then magnified and collimated by a lens group;

[0031] The Gaussian beam passing through the lens group is incident on a spatial light modulator loaded with an Airy beam mask, and is modulated by the spatial light modulator using zero-order light to form an excitation light that is a superposition of the Airy beam and the Gaussian beam;

[0032] Next, the excitation light is reduced in size and collimated by the 4F system, and then incident on the XY scanning galvanometer, and then scanned point by point by the XY scanning galvanometer. After that, the excitation light passes through the scanning lens, tube lens, and emission filter, and then irradiates the surface of the sample to be imaged through the dichroic plate and objective lens. Then, the excitation light interacts with the fluorescent markers in the sample to be imaged, and excites the fluorescent markers to produce fluorescence;

[0033] The fluorescence generated by the sample to be imaged is split by a two-color filter and transmitted to a photomultiplier tube for fluorescence image acquisition.

[0034] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0035] The present invention superimposes a non-diffracting Airy beam and a Gaussian beam to construct a scanning structured light microscopic imaging system of an Airy beam superimposed on a Gaussian beam. An electro-optic modulator modulates the Gaussian beam to generate a time-varying beam with non-sinusoidal intensity variation, and the beam is incident on a spatial light modulator loaded with an Airy beam mask after being amplified and collimated by a lens group. The spatial light modulator uses zero-order light for modulation to form an excitation light superimposed on the Airy beam and the Gaussian beam. By controlling the on and off of the spatial light modulator, seamless switching between beam modes (Gaussian beam, Gaussian+Airy beam) can be achieved. The Airy beam artifact is removed by precisely controlling the superposition generation and modulation of the non-diffracting Airy beam and the Gaussian beam. The superimposed excitation light is irradiated on a sample to be imaged after being processed by a 4F system, an XY scanning galvanometer, etc. to generate a fluorescence signal.

[0036] Among them, the superimposed excitation light uses a Gaussian beam to suppress the sidelobe effect of the Airy beam, thereby effectively removing artifacts in Airy beam imaging. This superposition method can retain the self-acceleration and non-diffraction characteristics of the Airy beam, while using the concentrated energy characteristics of the Gaussian beam to reduce the negative impact of the sidelobes. On this basis, combined with scanning structured light super-resolution microscopy technology, the lateral resolution of the imaging is further improved by scanning the imaged sample multiple times at different angles and positions. This scheme uses spatiotemporal modulation of structured light technology to break through the diffraction limit without changing other parameters of the optical system and achieve super-resolution imaging.

[0037] In summary, the present invention effectively overcomes the imaging artifact problem caused by the side lobes of the Airy beam, provides higher resolution and clearer microscopic imaging results, and is particularly suitable for the fields of biomedicine and materials science that require high-precision imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 A schematic diagram of the structure of a scanning structured light microscopic imaging system of an Airy beam superimposed on a Gaussian beam provided by the present invention;

[0040] Figure 2The simulation results of the superposition of the Airy beam and the Gaussian beam of the present invention, wherein (a) is the intensity distribution diagram of the Gaussian beam in the (x, y) plane, and the lower right corner is the total intensity; (b) is the intensity distribution diagram of the Airy beam in the (x, y) plane, and the lower right corner is the total intensity; (c) is the beam superposition diagram, and the lower right corner is the intensity ratio; (d) is the intensity distribution diagram of the Gaussian beam in the transverse (x, z) plane, and the lower right corner is the total intensity; (e) is the intensity distribution diagram of the Airy beam in the transverse (x, z) plane, and the lower right corner is the total light intensity; (f) is the beam superposition diagram, and the lower right corner is the intensity ratio;

[0041] Explanation of the accompanying drawings: 1. laser light source; 2. first half-wave plate; 3. electro-optic modulator; 4. reflector; 5. first lens; 6. second lens; 7. second half-wave plate; 8. spatial light modulator; 9. third lens; 10. fourth lens; 11. second reflector; 12. XY scanning galvanometer; 13. scanning lens; 14. tube lens; 15. emission filter; 16. dichroic film; 17. objective lens; 18. sample to be imaged; 19. bandpass filter; 20. converging lens; 21. photomultiplier tube; 22. computer. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The scanning structured light microscopy imaging system and method of the Airy beam superimposed on a Gaussian beam provided by the present invention accurately modulates the diffraction-free Airy beam and the Gaussian beam to superimpose a new excitation light through a spatial light modulator, thereby providing an efficient and innovative technical solution for removing Airy beam artifacts.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1 As shown, the scanning structured light microscopy imaging system of Airy beam superimposed on Gaussian beam provided by the embodiment of the present invention comprises: a laser light source 1, a first half-wave plate 2, an electro-optic modulator 3, a first reflector 4, a lens group, a second half-wave plate 7, a spatial light modulator 8, a 4F system, a second reflector 11, an XY scanning galvanometer 12, a scanning lens 13, a tube lens 14, an emission filter 15, a dichroic filter 16, an objective lens 17, and a bandpass filter 19, a converging lens 20, and a photomultiplier tube 21 arranged in sequence along the excitation light path;

[0046] The laser light source 1 is used to emit a Gaussian beam; the Gaussian beam emitted by the laser light source 1 passes through the first half-wave plate 2, the electro-optical modulator 3, the first reflector 4, the lens group, and the second half-wave plate 7 in sequence and is incident on the spatial light modulator 8, the spatial light modulator 8 is loaded with an Airy beam mask, and the incident Gaussian beam is modulated with zero-order light to form an excitation light in which the Airy beam and the Gaussian beam are superimposed;

[0047] The excitation light formed by superposition of the Airy beam and the Gaussian beam passes through the 4F system, the second reflector 11, the XY scanning galvanometer 12, the scanning lens 13, the tube lens 14, the emission filter 15, the dichroic filter 16, and the objective lens 17 in sequence, and then irradiates the sample 18 to be imaged. The excitation light interacts with the fluorescent marker in the sample 18 to be imaged, and excites the sample 18 to generate fluorescence.

[0048] The fluorescence generated by the sample 18 to be imaged passes through the objective lens 17 and the dichroic filter 16, and after the stray light is filtered out by the bandpass filter 19, it is focused to the photomultiplier tube 21 through the converging lens 20 to collect the fluorescence image.

[0049] In the above system structure, the first half-wave plate 2 is used to adjust the polarization state of the Gaussian light beam so that the polarization direction of the Gaussian light beam matches the polarization direction of the electro-optical modulator 3; the electro-optical modulator 3 modulates the Gaussian light beam into a modulated light beam whose light intensity changes periodically over time according to a sinusoidal function; the light Gaussian light beam passes through the first half-wave plate 2 and the electro-optical modulator 3 to generate a sinusoidal intensity modulated light beam with a significant modulation depth.

[0050] The lens group includes a first lens 5 and a second lens 6. The radius of the first lens 5 is smaller than the radius of the second lens 6. The Gaussian light beam incident on the lens group passes through the first lens 5 and the second lens 6 in sequence to be magnified and collimated.

[0051] To ensure the beam modulation effect, the second half-wave plate 7 is arranged between the lens group and the spatial light modulator 8. The second half-wave plate 7 is used to adjust the polarization direction of the Gaussian beam emitted through the lens group so that the polarization direction of the Gaussian beam is parallel to the liquid crystal plane of the spatial light modulator 8.

[0052] The 4F system includes a third lens 9 and a fourth lens 10, wherein the radius of the third lens 9 is greater than the radius of the fourth lens 10. The 4F system is used to reduce the size of the excitation light superimposed by the Airy beam and the Gaussian beam and collimate the excitation light so that the beam size of the excitation light is the same as the size of the Gaussian beam before passing through the lens group.

[0053] A second reflector 11 is arranged between the 4F system and the XY scanning galvanometer 12, and the second reflector 11 is used to change the optical path direction of the excitation light emitted by the 4F system so that the optical path direction of the excitation light is spatially conjugate with the XY scanning galvanometer 12. The optical path of the excitation light forms a conjugate relationship with the scanning plane of the XY scanning galvanometer. The XY scanning galvanometer 12 quickly changes the optical path direction of the excitation light so that the excitation light performs a two-dimensional scan on the surface of the sample to be imaged. The XY scanning galvanometer 12 is usually composed of two mutually perpendicular galvanometer mirrors, which control the scanning of the light beam on the X-axis and the Y-axis respectively. Due to the spatial conjugate relationship between the excitation light and the XY scanning galvanometer 12, high-precision scanning can be achieved, and each scanning point can accurately correspond to a position on the sample to be imaged.

[0054] Afterwards, the scanning lens 13 and the tube lens 14 are matched after the emission filter 15 to ensure that the entrance pupil of the XY scanning galvanometer 12 and the objective lens 17 are conjugated to achieve precise scanning imaging. The fluorescence signal is collected by the same objective lens 17 and separated from the main beam path using a dichroic filter 16. The fluorescence signal is focused to the photomultiplier tube (PMT) 21 via a converging lens 20 for detection. A bandpass filter 19 is set before the converging lens 2020 to filter out any residual stray light. By controlling the opening and closing of the spatial light modulator 8, seamless switching between beam modes (Gaussian beam, Airy + Gaussian beam) is achieved.

[0055] The system also includes a computer 22, which is electrically connected to the electro-optic modulator 3, the spatial light modulator 8, the XY scanning galvanometer 12 and the photomultiplier tube 21 respectively; the computer 22 is used to control the electro-optic modulator 3 to perform non-sinusoidal modulation on the Gaussian light beam, modulate the Gaussian light beam into a time-varying light beam with non-sinusoidal intensity changes, and is also used to control the spatial light modulator 8 to generate excitation light that is a superposition of the Airy beam and the Gaussian beam, and is also used to control the XY scanning galvanometer 12 to sequentially scan the excitation light spots focused with different intensities point by point to the sample to be imaged 18, and is also used to obtain a fluorescence image of the sample to be imaged 18 through the photomultiplier tube 21.

[0056] The present invention also provides a scanning structured light microscopy imaging method of an Airy beam superimposed on a Gaussian beam, which is applied to the above-mentioned scanning structured light microscopy imaging system of an Airy beam superimposed on a Gaussian beam, and comprises the following steps:

[0057] The laser light source 1 emits a Gaussian beam;

[0058] The Gaussian beam is modulated by the electro-optic modulator 3 and then magnified and collimated by the lens group;

[0059] The Gaussian beam passing through the lens group is incident on the spatial light modulator 8 loaded with the Airy beam mask, and is modulated by the spatial light modulator 8 using zero-order light to form an excitation light superimposed by the Airy beam and the Gaussian beam. Specifically, the power and phase of the Airy beam can be adjusted to appropriately overlap the Gaussian beam in space, thereby achieving the effect of suppressing the side lobe; wherein, the zero-order light is the part with the highest power in the SLM. If it is directly filtered out, the utilization rate of the light energy will be significantly reduced, resulting in a decrease in imaging efficiency. Therefore, the present invention uses zero-order light for modulation to improve the imaging efficiency;

[0060] Next, the excitation light is reduced in size and collimated by the 4F system, and then incident on the XY scanning galvanometer 12, and then scanned point by point by the XY scanning galvanometer 12. After that, the excitation light passes through the scanning lens 13 and the tube lens 14, and then irradiates the surface of the sample to be imaged 18 through the dichroic film 16 and the objective lens 17. Then, the excitation light interacts with the fluorescent marker in the sample to be imaged 18, and excites the fluorescent marker to produce fluorescence;

[0061] The fluorescence generated by the sample 18 to be imaged is split by the dichroic filter 16 and transmitted to the photomultiplier tube 21 for collecting the fluorescence image.

[0062] Specifically, the photomultiplier tube 21 collects the fluorescence signal generated by the sample to be imaged after the excitation light is scanned, and obtains a group of fluorescence structured light images corresponding to the fluorescence signal; wherein the group of fluorescence structured light images includes: a plurality of fluorescence structured light images; the orientation and phase of the excitation light pattern corresponding to each fluorescence structured light image are different. The computer 22 is used to extract the frequency components in each of the fluorescence structured light images, reset and superimpose the frequency components corresponding to the same orientation and different phases, and reconstruct the super-resolution image of the sample to be imaged according to the superimposed value group of the frequency components at each orientation.

[0063] Specifically, the principle of superposition of a non-diffracting Airy beam and a Gaussian beam:

[0064] A Gaussian beam has a Gaussian distribution in its cross section. Its electric field distribution can be expressed as:

[0065]

[0066] Where ω0 is the beam waist radius, which represents the spatial range of the beam in the transverse plane; ω z Represents the spatial extent of the beam in the vertical plane; is the spatial scale parameter; z represents the propagation distance of the light beam in the z-axis direction, k represents the vector wave, that is, the wave number of the light beam, and x0 represents the characteristic size, which usually refers to the lateral size at the beam waist position or the characteristic length related to the beam expansion range. x and y represent the coordinates of the light beam in the transverse plane, that is, the coordinates defined in the plane perpendicular to the propagation direction (transverse plane). z represents the coordinate of the light beam in the propagation direction, that is, the position of the light beam along the propagation axis (usually the z-axis).

[0067] Analyzing on the (x, y) plane, when z = 0, the electric field intensity distribution formula is:

[0068]

[0069] It can be seen from the formula that on the (x, y) plane, the intensity of the Gaussian beam reaches its maximum value at the center, and the energy is highly concentrated. When moving away from the center, the intensity decays rapidly exponentially.

[0070] In (x,y,z) space, the energy distribution is not only affected by the (x,y) plane, but also by the modulation along the z axis. As z increases, This is because, as z increases, the exponential term approaches zero, causing the overall beam intensity to decrease and the energy to spread out in space.

[0071] Airy beam is a non-diffracted beam with self-acceleration and oscillation characteristics. Its electric field distribution can be described by the Airy function:

[0072]

[0073] Here, the symbol Ai represents the Airy function, which is a special function for solving nonlinear differential equations and usually appears in the description of accelerated beams and diffraction phenomena. a is the attenuation coefficient, which controls the attenuation and amplitude of the beam, and i represents the imaginary term, which is related to the phase and is used to describe the phase change of the light wave. This formula describes an Airy beam that propagates at an accelerated speed along the x and y axes. The intensity and phase of the beam are affected by the parameters a, e, the spatial position x, y, and the imaginary phase term i. By adjusting these parameters, the propagation behavior of the beam and the light field distribution can be precisely controlled and described.

[0074] is the spatial scale parameter, and Z represents the propagation distance.

[0075] When z=0, the formula is:

[0076]

[0077] Airy beams exhibit a self-acceleration effect, and their intensity distribution has a main lobe and several side lobes in each dimension. a represents the attenuation factor of the Airy beam. In the (x,y) plane, the side lobes have a higher intensity, which is the key factor leading to image artifacts.

[0078] When two beams are superimposed, the total electric field distribution is defined by the linear superposition of their individual electric fields:

[0079] E total (x,y,z)=|E Gaussian (x,y,z)+E Airy (x,y,z) (5)

[0080] The relationship between light intensity I and electric field E is given by the following formula:

[0081] I(x,y,z)=|E(x,y,z)| 2 (6)

[0082] Therefore, the light intensity of the Airy beam, Gaussian beam and their superposition can be expressed as:

[0083] I Gaussian (x,y,z)=|E Gaussian (x,y,z)| 2 (7)

[0084] I Airy (x,y,z)=|E Airy (x,y,z)| 2 (8)

[0085] I total (x,y,z)=|E Gaussian (x,y,z)+E Airy (x,y,z)| 2 (9)

[0086] After expansion, we get:

[0087]

[0088] Among them, R e represents the real part, It reflects the mutual interference effect between the two beams; E Airy (x, y, z) represents the electric field strength of the Airy beam, E Gaussian (x, y, z) represents the electric field intensity of the Gaussian beam, and * represents the complex conjugate.

[0089] In order to quantify the intensity ratio R between the Airy beam and the Gaussian beam a , their intensity integrals over the entire beam area can be calculated and then the ratio can be determined:

[0090]

[0091] The ratio R a A quantitative assessment of the relative intensity contributions of Airy and Gaussian beams over the entire beam area is provided.

[0092] After establishing the theoretical framework, we simulate the propagation paths of different beams. The wavelength is set to 800nm. The Gaussian beam waist radius ω0 = 2, ω z =4, a=0.01. The simulation results are as follows Figure 2 As shown in the figure, the horizontal and vertical axes represent the normalized distance. Figure 2 (a) shows the intensity distribution of a Gaussian beam in the transverse (x, y) plane, where the energy is mainly concentrated in the center and the total intensity is 5016.5002. Each element of the intensity matrix represents the relative light intensity at a specific point in space, calculated as the square of the field amplitude modulus. Since there is no clear definition of physical units, the intensity and total intensity values ​​are dimensionless and are only used for relative comparison of intensity distributions. Figure 2 (b) shows the intensity distribution of the Airy beam in the transverse (x,y) plane. The main lobe is clearly visible, accompanied by several side lobes with lower intensity, with a peak intensity of 724.7594. These side lobes are also the main cause of artifacts in the image. Figure 2 (c) shows the superposition of two beams on a light field. As shown in the figure, after superposition with the more concentrated Gaussian beam, the energy of the side lobes in the Airy beam is significantly suppressed. The intensity ratio of the Gaussian beam to the Airy beam is calculated to be 6.7539. Figure 2 (d)-(f) show the simulation results of Gaussian beam, Airy beam and their superposition in the (xz) plane. The total intensity of Gaussian beam and Airy beam is similar, and the intensity ratio is close to 1. This observation indicates that when the two beams propagate along the z-axis, their intensities disperse as z increases, resulting in the two beams having almost the same intensity.

[0093] The present invention can effectively reduce the sidelobe intensity of the Airy beam by superimposing the Gaussian beam with the Airy beam. The Gaussian beam has the characteristics of high center intensity and low edge intensity, and can be used to "suppress" the sidelobe of the Airy beam. The power and phase of the Airy beam can be adjusted to appropriately overlap the Gaussian beam in space, thereby achieving the effect of suppressing the sidelobe.

[0094] The embodiment of the present invention can select a suitable Gaussian beam width so that it can cover the main peak of the Airy beam and effectively suppress the side lobe. By accurately controlling the phase relationship between the Gaussian beam and the Airy beam, the superposition effect can be further optimized to minimize the side lobe.

[0095] In microscopic imaging, the side lobes of the Airy beam may affect the clarity of the image. By superimposing Gaussian beams, the imaging quality can be improved and a clearer image can be obtained.

[0096] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A scanning structured light microscopy imaging system of Airy beam superimposed on Gaussian beam, characterized in that: include: A laser light source (1), an electro-optic modulator (3), a lens group, a spatial light modulator (8), a 4F system, an XY scanning galvanometer (12), a scanning lens (13), a tube lens (14), an emission filter (15), a dichroic filter (16), and an objective lens (17) are sequentially arranged along an excitation light path, and also includes a photomultiplier tube (21); The laser light source (1) is used to emit a Gaussian light beam; the Gaussian light beam emitted by the laser light source (1) passes through an electro-optic modulator (3) and a lens group in sequence and is incident on a spatial light modulator (8); the spatial light modulator (8) is loaded with an Airy beam mask, and the incident Gaussian light beam is modulated using zero-order light to form excitation light in which the Airy beam and the Gaussian beam are superimposed; The excitation light formed by superposition of the Airy beam and the Gaussian beam passes through the 4F system, the XY scanning galvanometer (12), the scanning lens (13), the tube lens (14), the emission filter (15), the dichroic plate (16), and the objective lens (17) in sequence, and then irradiates the sample to be imaged (18). The excitation light interacts with the fluorescent marker in the sample to be imaged (18), and excites the sample to be imaged (18) to generate fluorescence. The fluorescence generated by the sample to be imaged (18) passes through the objective lens (17) and the dichroic film (16) and is then transmitted to the photomultiplier tube (21) for collecting the fluorescence image.

2. The scanning structured light microscopy imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: The light intensity signal I of the excitation light superimposed by the Airy beam and the Gaussian beam total (x,y,z), the formula is as follows: Among them, R e represents the real part, It reflects the mutual interference effect between the two beams; E Airy (x, y, z) represents the electric field strength of the Airy beam, E Gaussian (x, y, z) represents the electric field intensity of the Gaussian beam, and * represents the complex conjugate; I Gaussian (x, y, z) represents the intensity of the Gaussian beam, and the formula is as follows: I Gaussian (x,y,z)=|E Gaussian (x,y,z)| 2 (7) I Airy (x,y,z) represents the intensity of the Airy beam, I Airy (x,y,z)=|E Airy (x,y,z)| 2 (8) When z = 0, the intensity ratio R between the Airy beam and the Gaussian beam is quantified. a , by calculating the integral of the intensity of the Airy beam and the Gaussian beam over the entire beam area, and then determining the ratio: The ratio R a A quantitative assessment of the relative intensity contributions of Airy and Gaussian beams over the entire beam area is provided.

3. The scanning structured light microscopy imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: A first half-wave plate (2) is also provided between the laser light source (1) and the electro-optic modulator (3), and the first half-wave plate (2) is used to adjust the polarization state of the Gaussian light beam; a first reflector (4) is also provided between the electro-optic modulator (3) and the lens group, and the Gaussian light beam adjusted by the electro-optic modulator (3) is reflected to the lens group through the first reflector (4).

4. The scanning structured light microscopy imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: The lens group comprises a first lens (5) and a second lens (6), the radius of the first lens (5) is smaller than the radius of the second lens (6), and a Gaussian light beam incident on the lens group passes through the first lens (5) and the second lens (6) in sequence to be magnified and collimated.

5. The scanning structured light microscopic imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: A second half-wave plate (7) is also provided between the lens group and the spatial light modulator (8), and the second half-wave plate (7) is used to adjust the polarization direction of the Gaussian light beam emitted through the lens group so that the polarization direction of the Gaussian light beam is parallel to the liquid crystal surface of the spatial light modulator (8).

6. The scanning structured light microscopic imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: The 4F system comprises a third lens (9) and a fourth lens (10), wherein the radius of the third lens (9) is greater than the radius of the fourth lens (10), and the 4F system is used to reduce the size of the excitation light formed by superimposing the Airy beam and the Gaussian beam, and to collimate the excitation light so that the beam size of the excitation light is the same as the size of the Gaussian beam before passing through the lens group.

7. The scanning structured light microscopic imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: A second reflector (11) is arranged between the 4F system and the XY scanning galvanometer (12), and the second reflector (11) is used to change the optical path direction of the excitation light emitted by the 4F system so that the optical path direction of the excitation light is spatially conjugate with the XY scanning galvanometer (12).

8. The scanning structured light microscopic imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: A bandpass filter (19) and a converging lens (20) are provided between the dichroic film (16) and the photomultiplier tube (21); the fluorescent signal emitted by the dichroic film (16) is focused onto the photomultiplier tube (21) through the converging lens (20) after stray light is filtered out by the bandpass filter (19).

9. The scanning structured light microscopic imaging system of Airy beam superimposed on Gaussian beam according to claim 1, characterized in that: The system further comprises a computer (22), wherein the computer (22) is electrically connected to the electro-optic modulator (3), the spatial light modulator (8), the XY scanning galvanometer (12) and the photomultiplier tube (21) respectively; the computer (22) is used to control the electro-optic modulator (3) to modulate the Gaussian light beam into a modulated light beam whose light intensity changes periodically over time according to a sine function, and is also used to control the spatial light modulator (8) to generate excitation light in which the Airy beam and the Gaussian beam are superimposed, and is also used to control the XY scanning galvanometer (12) to sequentially scan the excitation light spots focused with different intensities point by point to the sample to be imaged (18), and is also used to obtain a fluorescence image of the sample to be imaged (18) through the photomultiplier tube (21).

10. A scanning structured light microscopy imaging method of Airy beam superimposed on Gaussian beam, characterized in that: The scanning structured light microscopic imaging system of the Airy beam superimposed on the Gaussian beam as described in any one of claims 1 to 9 comprises the following steps: The laser light source (1) emits a Gaussian beam; The Gaussian beam is modulated by an electro-optic modulator (3), and then magnified and collimated by a lens group; The Gaussian beam passing through the lens group is incident on a spatial light modulator (8) loaded with an Airy beam mask, and is modulated by the spatial light modulator (8) using zero-order light to form an excitation light in which the Airy beam and the Gaussian beam are superimposed; Next, the excitation light is reduced in size and collimated by the 4F system, and then incident on the XY scanning galvanometer (12), and then scanned point by point by the XY scanning galvanometer (12). After that, the excitation light passes through the scanning lens (13), the tube lens (14) and the emission filter (15), and then irradiates the surface of the sample to be imaged (18) through the dichroic plate (16) and the objective lens (17). Then, the excitation light interacts with the fluorescent marker in the sample to be imaged (18), and excites the fluorescent marker to generate fluorescence; The fluorescence generated by the sample to be imaged (18) is split by a two-color film (16) and transmitted to a photomultiplier tube (21) for collecting a fluorescence image.

Images