CN112379516B - Multi-object-plane simultaneous imaging method based on digital multiplexing lens - Google Patents

Abstract

The invention proposes a simultaneous imaging method of multiple object planes based on a digital multiplexing lens. The digital multiplexing lens programmed and modulated by the liquid crystal spatial light modulator, combined with the axial multi-object plane simultaneous imaging system composed of the front group of the fixed focal length infinite cylindrical microscope objective lens, can image any cross-section within a certain depth range of the sample Clear, or multiple cross-sections are imaged clearly at the same time, forming an image plane with diffraction-limited image quality that is simultaneously shifted in the axial and lateral directions on the same imaging plane. The number of imaging planes of the system, the axial spacing and the lateral offset distance between the imaging planes can be controlled and adjusted in real time through programming. The invention can realize a flexible three-dimensional imaging system that does not need axial scanning, has time and space resolution at the same time, and has important practical application value in the fields of biomedical imaging, pharmacology, material science and the like.

Description

A Multi-object Simultaneous Imaging Method Based on Digital Multiplex Lens

technical field

The invention belongs to the field of optical imaging, and in particular relates to a multi-object plane simultaneous imaging method based on a digital multiplexing lens.

Background technique

Optical imaging technology, as a direct visualization tool for studying living phenomena in living cells, has always been the main challenge to achieve flexible time- and space-resolved imaging. Existing imaging techniques, including confocal laser scanning microscopy, two-photon laser scanning microscopy, multifocal multiphoton microscopy imaging, optical coherence tomography, etc., require lateral and axial scanning imaging of the sample, which limits imaging. speed, the time-resolved properties are lost.

Although the multi-focal plane parallel imaging method based on deformed grating can realize simultaneous multi-section imaging, its cross-section imaging capability is mainly concentrated in the lower diffraction orders 0 and ±1, and the diffraction energy of each order is not uniform. Based on twisted Damman grating and multi-object simultaneous imaging system, the problem of energy distribution inhomogeneity in cross-sectional imaging is solved, and more cross-sectional imaging is realized, but it involves complex processing technology and detection technology, and is flexible and real-time. Not enough, when the number of sections and the section interval are changed, the twisted Damman grating needs to be reprocessed.

SUMMARY OF THE INVENTION

In the present invention, ideal imaging lenses with different focal lengths and blazed gratings with different diffraction angles are inlaid together, and a digital multiplexing lens is generated by programming a liquid crystal spatial light modulator (PLUTO). A multi-object simultaneous imaging method based on digital multiplex lens is proposed. The imaging method can make the imaging of any section clear within a certain depth range of the sample, or the imaging of multiple sections at the same time is clear, with the same diffraction limit imaging quality, and the number of section imaging, section imaging interval, section lateral offset distance passes through Liquid crystal spatial light modulator (PLUTO) programming is controllable in real time. The present invention realizes the digital multiplexing lens function through the liquid crystal spatial light modulator, thereby realizing the focal lengths of the plurality of ideal imaging lenses and the diffraction angles of the plurality of blazed gratings respectively.

The technical solution of the present invention is a multi-object simultaneous imaging method based on a digital multiplexing lens, and the details are as follows:

Step 1: Build a multi-object simultaneous imaging system model of a digital multiplex lens.

Step 2: According to the constructed multi-object plane simultaneous imaging system model, according to the combination rule of the ideal optical system, by combining the focal length, magnification, image-side principal plane position, object-side principal plane position, and object of the combined imaging system The amount of distance change and the changed distance of the main plane of the combined imaging system on the object side change with the focal length of the ideal imaging lens, so as to realize the control of the number of cross-section imaging and the distance between cross-section imaging.

Step 3: establish the phase model of the ideal imaging lens in the liquid crystal spatial light modulator, establish the phase model of the blazed grating in the liquid crystal spatial light modulator; realize that each imaging section has different diffraction angles.

Step 4: According to the needs of the number of imaging sections and the imaging distance, set the number of ideal imaging lenses and the distance that the object-side principal plane of the combination system changes. The distance is combined with step 2 to calculate the focal length of the ideal imaging lens, the diffraction angle of the blazed grating is calculated through step 3, the phase model of the digital multiplexed lens in the liquid crystal spatial light modulator is constructed, and the digital multiplexed lens is realized through the programming modulation of the liquid crystal spatial light modulator Design functions of ideal imaging lenses and blazed gratings.

Preferably, the multi-object simultaneous imaging system model of the digital multiplex lens in step 1 includes:

an infinite barrel length microscope objective lens front group and a digital multiplexing lens, the digital multiplexing lens is located on the back focal plane of the infinite barrel length microscope objective lens front group;

The digital multiplexing lens is composed of multiple ideal imaging lenses and multiple blazed gratings; the multiple ideal imaging lenses are ideal imaging lenses with different focal lengths, and the multiple blazed gratings are blazed gratings with different diffraction angles; the The number of the ideal imaging lens and the blazed grating is equal, and both are n, n≥1 and n is an integer;

The ideal imaging lens and the blazed grating are inlaid together, and are generated by programming and modulation of a liquid crystal spatial light modulator;

Preferably, the focal length of the combined imaging system described in step 2 is:

f' _zi = f' _obj

Among them, f' _obj is the focal length of the front group of the infinite barrel length microscope objective, f' _zi is the focal length of the combined imaging system, that is, the image-side focal plane of the front group of the infinite barrel length microscope objective with the focal length f' _obj is superimposed For an ideal imaging lens with a focal length of f′ _i i∈[1,n], no matter how the focal length f′ _i of the ith ideal imaging lens changes, the focal length f′ _zi of the combined imaging system remains unchanged, and n is the focal length of the ideal imaging lens. quantity;

The magnification of the combined imaging system described in step 2 is:

β _zi = β

Among them, β is the magnification of the front group of the infinite barrel length microscope objective, and β _zi is the magnification of the combined imaging system, that is, the superimposed focal length of the image-side focal plane of the front group of the infinite barrel length microscope objective with the focal length _f'obj The ideal imaging lens is f' _i i∈[1,n], no matter how the focal length f _i ' of the ith ideal imaging lens changes, the magnification of the combined imaging system does not change with the change of f' _i , n is ideal the number of imaging lenses;

The position of the main plane of the image side of the combined imaging system described in step 2 is:

H'H' _zi = 0

Among them, H' is the principal plane of the image side of the front group of the infinite barrel length microscope objective, H' _zi is the principal plane of the image side of the combined imaging system, that is, the image side principal plane of the front group of the infinite barrel length microscope objective with the focal length f' _obj The image-side focal plane superimposes an ideal imaging lens with a focal length of f′ _i i∈[1,n]. No matter how the focal length f′ _i of the i-th ideal imaging lens changes, H′ _zi is always connected to the image-side principal plane of the front group of the objective lens. H' coincides, that is, the image plane of the combined imaging system remains unchanged and does not change with the change of f' _i , and n is the number of ideal imaging lenses;

The position of the object-side principal plane of the combined imaging system described in step 2 is:

H is the object-side principal plane of the front group of the infinite barrel length microscope objective, H _zi is the object side principal plane of the combined imaging system, that is, the image side focal plane of the front group of the infinite barrel length microscope objective with the focal length _f'obj Superimpose an ideal imaging lens with a focal length of f′ _i i∈[1,n], the object-side principal plane of the combined imaging system changes with the change of f′ _i , and n is the number of ideal imaging lenses;

The object distance position of the combined imaging system described in step 2 changes with f′ _i as follows:

Among them, l _zi is the object distance of the combined imaging system, l' is the image distance of the front group of the infinite tube long microscope objective, this formula shows that the distance of the combined imaging system object side change is equal to the combined system object side principal plane change distance, n is the number of ideal imaging lenses;

The distance of the change of the main plane of the composite system in the step 2 is:

Among them, Δzi is the distance that the object-side principal plane of the combined system changes after the _ith imaging lens is loaded, and n is the number of ideal imaging lenses;

Calculate the focal length of the ideal imaging lens described in step 2 by the distance changed by the object-side principal plane of the combination system described in step 2;

By changing the number of ideal imaging lenses, namely n and f _i ', it can be used to control the number of cross-section imaging and the distance between cross-section imaging, i∈[1,n]

By changing the diffraction angles θ _xi , θ _yi corresponding to each imaging section in the x, y directions, the lateral offset distance of the section can be controlled, and the corresponding diffraction angles θ _xi , θ _yi in the x, y directions are realized by blazed gratings;

Preferably, the phase model of the ideal imaging lens in the liquid crystal spatial light modulator described in step 3 is:

The digital multiplexing lens is a phase map generated by a liquid crystal spatial light modulator. According to Fourier optics theory, the phase modulation amount of the i-th ideal imaging lens to the imaging wavefront is:

where λ is the incident wavelength, x and y are the coordinates with the center of the lens as the origin, f _i ' is the focal length of the ith ideal imaging lens, and n is the number of ideal imaging lenses;

Let the pixel resolution of the liquid crystal spatial light modulator be M*N, the pixel center spacing be a, M is the number of rows of liquid crystal spatial light modulator pixels, and N is the number of columns of liquid crystal spatial light modulator pixels;

Taking the center of the liquid crystal spatial light modulator as the coordinate origin, the phase model of the ideal imaging lens with focal length f _i ' in the liquid crystal spatial light modulator can be expressed as:

In the formula, mod _2π represents the operation of taking the remainder of 2π, k is the first coefficient, l is the second coefficient, a is the pixel center distance, f _i ' is the focal length of the ith ideal imaging lens, and M is the liquid crystal spatial light modulator. The number of rows of pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and n is the number of ideal imaging lenses;

The phase model of the blazed grating in the liquid crystal spatial light modulator established in step 3 is:

In order to realize the imaging of different axial sections in different regions of the image plane without overlapping each other, the outgoing beams of ideal imaging lenses with different focal lengths should have different diffraction angles;

It is realized by using the liquid crystal spatial light modulator to generate a blazed grating. For the outgoing beam of the i-th ideal imaging lens with a focal length f _i ', the phase model distribution of the corresponding i-th blazed grating loaded is expressed as:

In the formula, T _xi is the grating period corresponding to the i-th ideal imaging lens in the x-direction in pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y-direction in pixels, and k is the first coefficient, l is the second coefficient, M is the number of rows of liquid crystal spatial light modulator pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and n is the number of ideal imaging lenses;

Each imaging section described in step 3 has a different diffraction angle:

After loading the i-th blazed grating, the diffraction angles of the imaging section beam corresponding to f _i ' in the x and y directions are:

Among them, a is the pixel center spacing, T _xi is the grating period corresponding to the i-th ideal imaging lens in the x-direction in pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y-direction in pixels, n is the number of ideal imaging lenses;

The size of the diffraction angle is related to T _xi and T _yi respectively, and the direction of the diffraction angle depends on the sign of k, l;

Preferably, the phase model of the digital multiplexing lens in the liquid crystal spatial light modulator in step 4 is:

where a is the pixel center spacing, f _i ' is the focal length of the ith ideal imaging lens, M is the number of rows of liquid crystal spatial light modulator pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and T _xi is The x-direction is the grating period corresponding to the i-th ideal imaging lens in pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y-direction in pixels, k is the first coefficient, and l is the second coefficient.

In the present invention, ideal imaging lenses with different focal lengths and blazed gratings with different diffraction angles are inlaid together, and a digital multiplexing lens is generated by programming a liquid crystal spatial light modulator (PLUTO). A multi-object simultaneous imaging method based on digital multiplex lens is proposed. The imaging method can make the imaging of any section clear within a certain depth range of the sample, or the imaging of multiple sections at the same time is clear, with the same diffraction limit imaging quality, and the number of section imaging, section imaging interval, section lateral offset distance passes through Liquid crystal spatial light modulator (PLUTO) programming is controllable in real time. The present invention realizes the digital multiplexing lens function through the liquid crystal spatial light modulator, thereby realizing the focal lengths of the plurality of ideal imaging lenses and the diffraction angles of the plurality of blazed gratings respectively.

The invention can realize a flexible three-dimensional imaging system that does not need axial scanning, has time and space resolution at the same time, and has important practical application value in the fields of biomedical imaging, pharmacology, material science and the like.

Description of drawings

Figure 1: Multi-object simultaneous imaging system with digital multiplex lens.

Figure 2: Schematic diagram of the focal length of the combined imaging system.

Figure 3: Schematic diagram of a two-dimensional matrix.

Figure 4: The calibrated phase grayscale map.

Figure 5: Flow chart of the method of the present invention.

Detailed ways

In order to facilitate the understanding and implementation of the present invention by those of ordinary skill in the art, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, but not to limit it. this invention.

Summary of the embodiments of the present invention, the liquid crystal spatial light modulator adopts the PLUTO-VIS liquid crystal spatial light modulator produced by HOLOEYE company in Germany, the image size is 15.36mm×8.64mm, the resolution M×N is 1920×1080, and the pixel size is 8μm, and the interval between pixels is 1μm, the size a of a single pixel is 9μm

Below in conjunction with Fig. 1 to Fig. 5, describe the specific embodiment of the present invention as follows:

A multi-object simultaneous imaging method based on a digital multiplexing lens, the details are as follows:

Step 1: Build a multi-object simultaneous imaging system model of a digital multiplex lens, as shown in Figure 1.

The multi-object simultaneous imaging system model of the digital multiplex lens in step 1 includes:

an infinite barrel length microscope objective lens front group and a digital multiplexing lens, the digital multiplexing lens is located on the back focal plane of the infinite barrel length microscope objective lens front group;

The multi-object plane simultaneous imaging system of the digital multiplexing lens adopts helium-neon laser as the illumination light source, the wavelength λ=0.6328μ, the focal length of the front group of the infinite barrel long objective lens is selected f' _obj =25mm, the numerical aperture NA=0.25, the magnification β= 10 ^× ;

The digital multiplexing lens is composed of multiple ideal imaging lenses and multiple blazed gratings; the multiple ideal imaging lenses are ideal imaging lenses with different focal lengths, and the multiple blazed gratings are blazed gratings with different diffraction angles; the The number of the ideal imaging lens and the blazed grating is equal, and both are n=9, n≥1 and n is an integer;

The ideal imaging lens and the blazed grating are inlaid together, and are generated by programming and modulation of a liquid crystal spatial light modulator;

Step 2: According to the constructed multi-object plane simultaneous imaging system model, according to the combination rule of the ideal optical system, by combining the focal length, magnification, image-side principal plane position, object-side principal plane position, and object of the combined imaging system The amount of distance change and the changed distance of the main plane of the combined imaging system on the object side change with the focal length of the ideal imaging lens, so as to realize the control of the number of cross-section imaging and the distance between cross-section imaging.

As shown schematically in Figure 2;

The focal length of the combined imaging system described in step 2 is:

f' _zi = f' _obj

Among them, f' _obj is the focal length of the front group of the infinite barrel length microscope objective, f' _zi is the focal length of the combined imaging system, that is, the image-side focal plane of the front group of the infinite barrel length microscope objective with the focal length f' _obj is superimposed For an ideal imaging lens with a focal length of f′ _i i∈[1,n], no matter how the focal length f′ _i of the ith ideal imaging lens changes, the focal length f′ _zi of the combined imaging system remains unchanged, and n is the focal length of the ideal imaging lens. quantity;

The focal length f′ _i of the ith ideal imaging lens is determined according to the requirements of the cross-sectional imaging distance and the distance changed by the object-side principal plane of the combined system in step 2 of the Summary of the Invention;

Among them, for the P ₀ section, Δz ₀ =0, f ₀ '=0, and for the P ₁ to P ₈ sections, the setting requirements are Δz ₁ =Δz ₂ =...=Δz ₈ =0.1mm, as shown in Figure 1;

f' ₁ =6250mm, f' ₂ =3125mm, f' ₃ =2083.33mm, f' ₄ =1562.5mm

f' ₅ =1250mm, f' ₆ =1041.67mm, f' ₇ =892.85mm, f' ₈ =781.25mm

The magnification of the combined imaging system described in step 2 is:

β _zi = β

Among them, β is the magnification of the front group of the infinite barrel length microscope objective, and β _zi is the magnification of the combined imaging system, that is, the superimposed focal length of the image-side focal plane of the front group of the infinite barrel length microscope objective with the focal length _f'obj For an ideal imaging lens of f′ _i i∈[1,n], no matter how the focal length f′ _i of the ith ideal imaging lens changes, the magnification of the combined imaging system does not change with the change of f′ _i , and n is ideal the number of imaging lenses;

The position of the main plane of the image side of the combined imaging system described in step 2 is:

H'H' _zi = 0

Among them, H' is the principal plane of the image side of the front group of the infinite barrel length microscope objective, H' _zi is the principal plane of the image side of the combined imaging system, that is, the image side principal plane of the front group of the infinite barrel length microscope objective with the focal length f' _obj The image-side focal plane superimposes an ideal imaging lens with a focal length of f′ _i i∈[1,n]. No matter how the focal length f′ _i of the i-th ideal imaging lens changes, H′ _zi is always connected to the image-side principal plane of the front group of the objective lens. H' coincides, that is, the image plane of the combined imaging system remains unchanged and does not change with the change of f' _i , and n is the number of ideal imaging lenses;

The position of the object-side principal plane of the combined imaging system described in step 2 is:

H is the object-side principal plane of the front group of the infinite barrel length microscope objective, H _zi is the object side principal plane of the combined imaging system, that is, the image side focal plane of the front group of the infinite barrel length microscope objective with the focal length _f'obj Superimpose an ideal imaging lens with a focal length of f′ _i i∈[1,n], the object-side principal plane of the combined imaging system changes with the change of f′ _i , and n is the number of ideal imaging lenses;

The object distance position of the combined imaging system described in step 2 changes with f′ _i as follows:

Among them, is the object distance of l _zi combined imaging systems, and l' is the image distance of the front group of the infinite tube long microscope objective. n is the number of ideal imaging lenses;

The distance of the change of the main plane of the composite system in the step 2 is:

Among them, Δzi is the distance that the object-side principal plane of the combined system changes after the _ith imaging lens is loaded, and n is the number of ideal imaging lenses;

Calculate the focal length of the ideal imaging lens described in step 2 by the distance changed by the object-side principal plane of the combination system described in step 2;

By changing the number of ideal imaging lenses, namely n and f _i ', it can be used to control the number of cross-section imaging and the distance between cross-section imaging, i∈[1,n]

By changing the diffraction angles θ _xi , θ _yi corresponding to each imaging section in the x, y directions, the lateral offset distance of the section can be controlled, and the corresponding diffraction angles θ _xi , θ _yi in the x, y directions are realized by blazed gratings;

Step 3: establish the phase model of the ideal imaging lens in the liquid crystal spatial light modulator, establish the phase model of the blazed grating in the liquid crystal spatial light modulator; realize that each imaging section has different diffraction angles.

The phase model of the ideal imaging lens in the liquid crystal spatial light modulator described in step 3 is:

The digital multiplexing lens is a phase map generated by a liquid crystal spatial light modulator. According to Fourier optics theory, the phase modulation amount of the i-th ideal imaging lens to the imaging wavefront is:

where λ is the incident wavelength, x and y are the coordinates with the center of the lens as the origin, f _i ' is the focal length of the ith ideal imaging lens, and n is the number of ideal imaging lenses;

Let the pixel resolution of the liquid crystal spatial light modulator be M*N, the pixel center spacing be a, M is the number of rows of liquid crystal spatial light modulator pixels, and N is the number of columns of liquid crystal spatial light modulator pixels;

Taking the center of the liquid crystal spatial light modulator as the coordinate origin, the phase model of the ideal imaging lens with focal length f _i ' in the liquid crystal spatial light modulator can be expressed as:

In the formula, mod _2π represents the operation of taking the remainder of 2π, k is the first coefficient, l is the second coefficient, a is the pixel center distance, f _i ' is the focal length of the ith ideal imaging lens, and M is the liquid crystal spatial light modulator. The number of rows of pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and n is the number of ideal imaging lenses;

The phase model of the blazed grating in the liquid crystal spatial light modulator established in step 3 is:

In order to realize the imaging of different axial sections in different regions of the image plane without overlapping each other, the outgoing beams of ideal imaging lenses with different focal lengths should have different diffraction angles;

It is realized by using the liquid crystal spatial light modulator to generate a blazed grating. For the outgoing beam of the i-th ideal imaging lens with a focal length f _i ', the phase model distribution of the corresponding i-th blazed grating loaded is expressed as:

In the formula, T _xi is the grating period corresponding to the i-th ideal imaging lens in the x-direction in pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y-direction in pixels, and k is the first coefficient, l is the second coefficient, M is the number of rows of liquid crystal spatial light modulator pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and n is the number of ideal imaging lenses;

Each imaging section described in step 3 has a different diffraction angle:

After loading the i-th blazed grating, the diffraction angles of the imaging section beam corresponding to f _i ' in the x and y directions are:

Among them, a is the pixel center spacing, T _xi is the grating period corresponding to the i-th ideal imaging lens in the x-direction in pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y-direction in pixels, n is the number of ideal imaging lenses;

The size of the diffraction angle is related to T _xi and T _yi respectively, and the direction of the diffraction angle depends on the sign of k, l;

Step 4: According to the needs of the number of imaging sections and the imaging distance, set the number of ideal imaging lenses and the distance that the object-side principal plane of the combination system changes. The distance is combined with step 2 to calculate the focal length of the ideal imaging lens, the diffraction angle of the blazed grating is calculated through step 3, the phase model of the digital multiplexed lens in the liquid crystal spatial light modulator is constructed, and the digital multiplexed lens is realized through the programming modulation of the liquid crystal spatial light modulator Design functions of ideal imaging lenses and blazed gratings.

The phase model of the digital multiplexing lens in the liquid crystal spatial light modulator in step 4 is:

where a is the pixel center spacing, f _i is the focal length of the ith ideal imaging lens, M is the number of rows of liquid crystal spatial light modulator pixels, N is the number of columns of liquid crystal spatial light modulator pixels, and T _xi is x The direction is the grating period corresponding to the i-th ideal imaging lens in the unit of pixels, T _yi is the grating period corresponding to the i-th ideal imaging lens in the y direction in the unit of pixel, k is the first coefficient, and l is the second coefficient.

The phase distribution of the digital multiplexing lens is shown in Table 1:

Table 1 Phase distribution of digital multiplexing lens

Step 5: Call Matlab to generate a two-dimensional matrix, and assign the initial values of the nine phase distributions to the two-dimensional matrix randomly, as shown in Figure 3.

Step 6: Figure 4 shows the calibrated phase grayscale map, calculates the phase modulation amount corresponding to each pixel in the matrix according to the phase expression in Table 1, and generates a grayscale matrix.

The working process of PLUTO is to control the phase modulation amount of each pixel by changing the addressing voltage. When PLUTO leaves the factory, the manufacturer has mapped the driving voltage to the gray value displayed by the computer. The manufacturer gives the (gray-phase) customer search However, specific to each device, the device needs to be re-calibrated to obtain the grayscale-phase calibration curve as shown in Figure 4, and the grayscale corresponding to the curve is loaded on the PLUTO driver software to achieve the required phase modulation.

Step 7: Use the Imwrite function to generate a grayscale image and load it on the spatial light modulator.

It should be understood that the parts not described in detail in this specification belong to the prior art.

It should be understood that the above description of the preferred embodiments is relatively detailed, and therefore should not be considered as a limitation on the protection scope of the patent of the present invention. In the case of the protection scope, substitutions or deformations can also be made, which all fall within the protection scope of the present invention, and the claimed protection scope of the present invention shall be subject to the appended claims.

Claims (3)

1. A multi-object-plane simultaneous imaging method based on a digital multiplexing lens is characterized by comprising the following steps:

step 1: constructing a multi-object-plane simultaneous imaging system model of the digital multiplexing lens;

step 2: according to the constructed multi-object-plane simultaneous imaging system model and the combination rule of an ideal optical system, the control of the number of cross-section imaging and the cross-section imaging distance is realized by combining the focal length, the magnification, the image side main plane position, the object side main plane position of the imaging system, the object distance variation of the combined imaging system and the change distance of the object side main plane of the combined imaging system with the focal length change of an ideal imaging lens;

and step 3: establishing a phase model of an ideal imaging lens in the liquid crystal spatial light modulator, and establishing a phase model of a blazed grating in the liquid crystal spatial light modulator; different diffraction angles of each imaging section are realized;

and 4, step 4: setting the number of ideal imaging lenses and the changed distance of the object side main plane of the combined system according to the requirements of the number of imaging sections and the imaging interval, calculating the focal length of the ideal imaging lenses by combining the set number of the ideal imaging lenses and the changed distance of the object side main plane of the combined system with the step 2, calculating the diffraction angle of the blazed grating by the step 3, constructing a phase model of the digital multiplexing lens on the liquid crystal spatial light modulator, and realizing the design functions of the ideal imaging lenses and the blazed grating in the digital multiplexing lens by the programmed modulation of the liquid crystal spatial light modulator;

the multiple object plane simultaneous imaging system model of the digital multiplexing lens in the step 1 comprises:

the digital multiplexing lens is positioned on the back focal plane of the front group of the infinite cylinder length microobjective;

the digital multiplexing lens is composed of a plurality of ideal imaging lenses and a plurality of blazed gratings; the plurality of ideal imaging lenses are ideal imaging lenses with different focal lengths, and the plurality of blazed gratings are blazed gratings with different diffraction angles; the number of the ideal imaging lens is equal to that of the blazed grating, the ideal imaging lens and the blazed grating are both n, n is more than or equal to 1, and n is an integer;

the ideal imaging lens and the blazed grating are embedded together and are generated by programming modulation of a liquid crystal spatial light modulator;

step 2, the focal length of the combined imaging system is as follows:

f′_zi＝f′_obj

wherein, f'_objIs set as the focal length of the front group of the microscope objective lens with infinite tube length, f'_ziOf combined imaging system, i.e. at focal length f'_objF 'is superposed on the image focal plane of the front group of the infinite tube length microscope objective lens'_ii∈[1,n]Irrespective of the focal length f 'of the i-th ideal imaging lens'_iHow to vary, the focal length f 'of the imaging system is combined'_ziKeeping the same, wherein n is the number of ideal imaging lenses;

and 2, the magnification of the combined imaging system is as follows:

β_zi＝β

wherein beta is the magnification of the front group of the microscope objective with infinite cylinder length, beta_ziMagnification for combined imaging system, i.e. at focal length f'_objF 'is superposed on the image focal plane of the front group of the infinite tube length microscope objective lens'_ii∈[1,n]Irrespective of the focal length f 'of the i-th ideal imaging lens'_iHow varied, the magnification of the combined imaging system is not f'_iN is the number of ideal imaging lenses;

the image space main plane position of the combined imaging system in the step 2 is as follows:

H'H′_zi＝0

wherein H ' is the image side main plane, H ' of the front group of the infinite tube length microscope objective lens '_ziIs the image-side principal plane of the combined imaging system, i.e. at focal length f'_objImage space focal plane superposition focal of front group of infinite tube length microscope objectiveDistance is f'_ii∈[1,n]Irrespective of the focal length f 'of the i-th ideal imaging lens'_iHow to vary, H'_ziAlways coincides with the image-side principal plane H 'of the objective lens front group, i.e. the image plane of the combined imaging system remains unchanged and does not follow f'_iN is the number of ideal imaging lenses;

the main plane position of the object space of the combined imaging system in the step 2 is as follows:

i∈[1,n]

h is the principal plane of object space of the front group of the microscope objective with infinite tube length, H_ziIs the object-side principal plane of the combined imaging system, i.e. at focal length f'_objF 'is superposed on the image focal plane of the front group of the infinite tube length microscope objective lens'_ii∈[1,n]Of the combined imaging system, object-side principal plane with f'_iN is the number of ideal imaging lenses;

step 2 object distance position with f 'of combined imaging system'_iThe change is as follows:

i∈[1,n]

wherein l_ziThe distance of the object space of the combined imaging system is l' is the image distance of the front group of the infinite tube-length microscope objective, the formula shows that the distance of the object space change of the combined imaging system is equal to the distance of the change of the main plane of the object space of the combined system, and n is the number of ideal imaging lenses;

the changed distance of the object space main plane of the combined system in the step 2 is as follows:

i∈[1,n]

wherein, Δ z_iThe distance changed by the main plane of the object space of the combined system after the ith imaging lens is loaded is n, and the n is the number of ideal imaging lenses;

calculating the focal length of the ideal imaging lens in the step 2 according to the changed distance of the object main plane of the combined system in the step 2;

by varying the number of ideal imaging lenses, i.e. n and f'_iCan be used for controlling the number of cross-section imaging and the cross-section imaging interval, i belongs to [1, n ]]

By changing the corresponding diffraction angle theta of each imaging section in the x and y directions_x-i，θ_y-iThe transverse offset distance of the cross section and the corresponding diffraction angle theta in the x and y directions can be controlled_x-i，θ_y-iBy means of blazed gratings.

2. The method of claim 1, wherein the method comprises:

step 3, establishing a phase model of the ideal imaging lens in the liquid crystal spatial light modulator is as follows:

the digital multiplexing lens is a phase diagram generated by a liquid crystal spatial light modulator, and according to the Fourier optics theory, the phase modulation amount of the ith ideal imaging lens on the imaging wavefront is as follows:

i∈[1,n]

wherein λ is an incident wavelength, x, y are coordinates with the center of the lens as an origin, and f'_iIs the focal length of the ith ideal imaging lens, and n is the number of the ideal imaging lenses;

setting the pixel resolution of the liquid crystal spatial light modulator as M x N, the pixel center distance as a, M being the number of rows of the liquid crystal spatial light modulator pixels, and N being the number of columns of the liquid crystal spatial light modulator pixels;

the focal length is f 'by taking the center of the liquid crystal spatial light modulator as the origin of coordinates'_iThe phase model of the ideal imaging lens in the liquid crystal spatial light modulator can be expressed as:

i∈[1,n]

in the formula (mod)_2πRepresenting 2 pi complementation operation, k being a first coefficient, l being a second coefficient, a being a pixel center distance, f'_iThe focal length of the ith ideal imaging lens is, M is the number of rows of the pixels of the liquid crystal spatial light modulator, N is the number of columns of the pixels of the liquid crystal spatial light modulator, and N is the number of the ideal imaging lenses;

and 3, establishing a phase model of the blazed grating in the liquid crystal spatial light modulator:

in order to realize that different axial section images are not overlapped in different areas of an image plane, emergent light beams of ideal imaging lenses with different focal lengths have different diffraction angles;

realized by generating a blazed grating with a liquid crystal spatial light modulator, for a focal length of f'_iThe loaded phase model distribution of the corresponding ith blazed grating of the outgoing beam of the ith ideal imaging lens is expressed as:

i∈[1,n]

in the formula, T_x-iIs the grating period, T, corresponding to the ith ideal imaging lens in the x direction by taking the pixel as a unit_y-iIs a y directionIn the grating period corresponding to the ith ideal imaging lens taking a pixel as a unit, k is a first coefficient, l is a second coefficient, M is the number of rows of pixels of the liquid crystal spatial light modulator, N is the number of columns of the pixels of the liquid crystal spatial light modulator, and N is the number of the ideal imaging lenses;

step 3, each imaging section has different diffraction angles:

f 'after loading the ith blazed grating'_iThe diffraction angles of the imaging cross-section light beams in the x and y directions are respectively as follows:

i∈[1,n]

wherein a is the pixel center-to-center distance, T_x-iIs the grating period, T, corresponding to the ith ideal imaging lens in the x direction by taking the pixel as a unit_y-iThe grating period corresponding to the ith ideal imaging lens is in the y direction by taking a pixel as a unit, and n is the number of the ideal imaging lenses;

the magnitude of the diffraction angle is respectively equal to T_x-iAnd T_y-iIn this regard, the direction of the diffraction angle depends on the sign of k, l.

3. The method of claim 1, wherein the method comprises:

step 4, the phase model of the digital multiplexing lens in the liquid crystal spatial light modulator is as follows:

i∈[1,n]

wherein a is pixel center distance, f'_iIs the focal length of the ith ideal imaging lens,m is the number of rows of liquid crystal spatial light modulator pixels, N is the number of columns of liquid crystal spatial light modulator pixels, T_x-iIs the grating period, T, corresponding to the ith ideal imaging lens in the x direction by taking the pixel as a unit_y-iThe grating period corresponding to the ith ideal imaging lens is in the y direction by taking a pixel as a unit, k is a first coefficient, and l is a second coefficient.

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