Lensless microscopic imaging device

Abstract

The utility model is applicable to the technical field of lensless microscopic imaging equipment, and provides a lensless microscopic imaging device, which comprises a light source, a coupling-in grating, an optical waveguide, a coupling-out grating and an image sensor, and is characterized in that the light source is used for emitting laser, and the coupling-in grating is arranged opposite to the light source and is used for enabling the laser to generate primary diffraction to form first diffraction light; the coupling-in grating is arranged at the position, close to the first end, of the optical waveguide, the coupling-in grating can guide the first diffracted light into the optical waveguide, and the optical waveguide is used for transmitting the first diffracted light from the first end to the second end; the coupling-out grating is arranged at the position, close to the second end, of the optical waveguide and used for enabling the first diffraction light to be subjected to secondary diffraction to form second diffraction light and leading out the second diffraction light from the optical waveguide; and the image sensor is arranged opposite to the coupling-out grating and is used for forming a coaxial hologram carrying sample information under the irradiation of the secondary diffraction light. The axial distance between the light source and the sample can be effectively reduced, and then the axial thickness of the imaging device is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of lensless microscopic imaging, and more specifically, to a lensless microscopic imaging device. Background Art

[0002] At present, lensless microscopy abandons the lenses required by traditional optical imaging systems and uses algorithms to reconstruct microscopic images. According to different imaging principles, lensless microscopy can be roughly divided into three forms: shadow imaging, holographic imaging and mask imaging.

[0003] Among them, shadow imaging uses an incoherent light source to illuminate the sample, and its shadow is directly projected onto the photoelectric sensor array. When the sample is very close to the camera sensor, the sensor obtains a shadow image. The closer the distance, the clearer the image, and vice versa. Therefore, this scheme requires the sample to be as close to the sensor surface as possible (usually less than 500μm), which is not feasible for samples with a certain depth such as volume imaging and optofluidic imaging, which greatly limits its application scenarios. It is currently only used in laboratory chip microscopes.

[0004] Holographic imaging uses coherent or partially coherent light sources, such as laser diodes, light-emitting diodes with pinhole filtering, etc., to illuminate the sample and obtain the sample hologram directly on the camera sensor in a coaxial holographic manner. Compared with the other two forms, holographic imaging not only retains the advantages of full-target imaging, but also contains a variety of information such as the sample's absorption rate, refractive index, and three-dimensional position in the hologram. Through subsequent reconstruction algorithms, the sample's amplitude map, phase map, three-dimensional distribution, etc. can be obtained.

[0005] Mask imaging generally requires a relatively high intensity illumination light source to excite the linear or nonlinear (fluorescence) scattered light of the sample, and then encodes the scattered light of the sample through a mask plate to form an image carrying the sample information on the sensor. After decoding the encoded image, a microscopic image of the sample can be obtained. In the form of mask imaging, the mask plate is a key light field modulation device, and its types include microlens arrays, phase plates, amplitude plates, metasurface arrays, etc. Their advantage is that they are very thin, which greatly compresses the space required by traditional objective lenses (lens groups), making the imaging system highly integrated and compact.

[0006] The above three forms of lensless microscopy generally require an active light source to illuminate the sample. However, due to the limited divergence angle and coherence of the light source, in order to achieve full field of view and high coherence illumination, the light source often needs to be a certain distance away from the sample (usually more than a few centimeters), which to a certain extent limits the compactness of the entire lensless imaging system and makes the overall volume of the lensless imaging system larger.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0008] The purpose of the embodiments of the present application is to provide a lensless microscopic imaging device, aiming to solve the technical problem of the large overall volume of the lensless microscopic imaging system in the prior art.

[0009] To achieve the above-mentioned purpose, the technical solution adopted in this application is to provide a lensless microscopic imaging device, comprising:

[0010] A light source for emitting laser light;

[0011] A coupling grating is arranged opposite to the light source and is used to cause the laser to diffract once to form a first diffracted light;

[0012] An optical waveguide, wherein the optical waveguide has a first end and a second end that are arranged opposite to each other, and an incoupling grating is arranged at a position of the optical waveguide close to the first end, and the incoupling grating can guide the first diffracted light into the optical waveguide, and the optical waveguide is used to propagate the first diffracted light from the first end to the second end;

[0013] An outcoupling grating is arranged at a position of the optical waveguide close to the second end, and is used to make the first diffracted light undergo secondary diffraction to form a second diffracted light, and then guide the second diffracted light out of the optical waveguide;

[0014] The image sensor is arranged opposite to the outcoupling grating, and is used for forming a coaxial hologram carrying sample information under the illumination of the secondary diffraction light.

[0015] The lensless microscopic imaging device provided by the present application has at least the following beneficial effects: the laser emitted by the light source is diffracted once by the coupling grating to form the first diffracted light, and the first diffracted light is introduced into the optical waveguide, the optical waveguide serves as the propagation medium of the first diffracted light, so that the first diffracted light propagates from the first end to the second end in the optical waveguide, and the first diffracted light is diffracted twice by the coupling grating to form the second diffracted light, and the second diffracted light is guided out of the optical waveguide at the coupling grating, thereby converting the long-distance axial propagation between the light source and the sample into lateral propagation along the length direction of the optical waveguide, thereby compressing the axial distance between the light source and the sample, and further reducing the axial thickness of the imaging device. The axial distance between the light source and the coupling grating is less than 5 mm, the axial distance between the coupling grating and the sample is less than 5 mm, and the axial distance between the sample and the image sensor is less than 3 mm. The overall axial thickness of the device of the present application is less than 1 cm, which greatly shortens the axial distance between the light source and the sample.

[0016] At the same time, through the multi-order diffraction effect of the import grating and the export grating, the multi-order diffraction light is exported from the export grating and irradiated onto the sample, and the sample is illuminated simultaneously by the second diffraction light of multiple different angles. Under the irradiation of the second diffraction light, the image sensor forms a coaxial hologram carrying the sample information, realizing multi-view coaxial holographic microscopic imaging. In addition, the first diffraction light and the second diffraction light can retain the coherence of the laser emitted by the light source, thereby realizing high-coherence lensless holographic three-dimensional microscopic imaging.

[0017] In one possible design, the light source and the image sensor are disposed on the same side of the optical waveguide.

[0018] By utilizing the above technical solution, by arranging the light source and the image sensor on the same side of the optical waveguide, the structure of the light source, the optical waveguide and the image sensor is made more compact, thereby reducing the axial distance between the light source, the optical waveguide and the image sensor and reducing the axial thickness of the imaging device.

[0019] In a possible design, the light source emits laser light along a first direction, and the first direction is perpendicular to the plane where the coupling-in grating is located.

[0020] By utilizing the above technical solution, the light source is made to emit laser light in a direction perpendicular to the plane where the coupling-in grating is located, thereby ensuring that the first diffracted light diffracted from the right side of the normal line has greater energy.

[0021] In a possible design, a glass slide is further included. The glass slide is arranged between the out-coupling grating and the image sensor, and the glass slide is parallel to the plane where the out-coupling grating is located.

[0022] By utilizing the above-mentioned technical solution, by arranging a glass slide between the out-coupling grating and the image sensor and placing the sample on the glass slide, the second diffraction lights of multiple diffraction orders derived from the out-coupling grating can be respectively irradiated onto the glass slide, thereby directly forming a hologram carrying sample information on the image sensor in a transmission coaxial holographic manner; by making the glass slide parallel to the plane where the out-coupling grating is located, the second diffraction lights of multiple diffraction orders derived from the out-coupling grating can maintain a large energy and irradiate the sample.

[0023] In a possible design, it also includes a shell, the light source, the optical waveguide, and the image sensor are all arranged in the shell, a first transparent window is arranged at a position of the shell opposite to the coupling-out grating, a second transparent window is arranged at a position of the shell opposite to the image sensor, the first transparent window and the second transparent window are arranged opposite to each other, and a glass slide is arranged on the second transparent window.

[0024] By using the above technical solution, the light source, the optical waveguide and the image sensor are all arranged in the housing, making the device more compact; by arranging a first transparent window and a second transparent window on the housing, the first transparent window and the second transparent window are arranged opposite to each other, thereby providing an illumination channel for the diffracted light, so that the second diffracted light of multiple diffraction orders derived from the coupling grating are respectively irradiated on the glass slide, thereby directly forming a hologram carrying sample information on the image sensor in a transmission coaxial holographic manner.

[0025] In a possible design, the housing is a groove-shaped structure, and a first cavity and a second cavity are formed in the housing opposite to each other, and one end of the first cavity is connected to one end of the second cavity through a third cavity;

[0026] The optical waveguide is arranged in the first cavity, the image sensor is arranged in the second cavity, the light source is arranged in the third cavity, the first transparent window is arranged on the cavity wall of the first cavity close to the second cavity, and the second transparent window is arranged on the cavity wall of the second cavity close to the first cavity.

[0027] By utilizing the above technical solution, the axial thickness of the housing is effectively reduced, the volume of the device is reduced, and the components of the device are made more compact, which is beneficial to the lightweight design of the device.

[0028] In a possible design, the thickness of the housing in the second direction is less than 1 cm, and the second direction is parallel to the height direction of the optical waveguide.

[0029] By utilizing the above technical solution, the axial thickness of the shell is reduced to less than 1 cm, which effectively reduces the volume of the device and makes the various components of the device more compact, which is conducive to the lightweight design of the device.

[0030] In a possible design, the angle between the first-order diffracted light diffracted from the side of the normal line of the coupling-in grating close to the coupling-out grating and the normal line is the diffraction angle of the first-order diffracted light, and the refractive index of the optical waveguide satisfies:

[0031] n2 / n1 <sinθ1=λ / d

[0032] Wherein, n1 is the refractive index of the optical waveguide, n2 is the refractive index of the medium outside the optical waveguide, θ1 is the diffraction angle of the first-order diffracted light, λ is the wavelength of the laser, and d is the grating constant of the coupled grating.

[0033] By utilizing the above technical solution, all positive-order diffracted lights can be totally reflected in the optical waveguide, effectively increasing the energy of the first diffracted light totally reflected in the optical waveguide, so as to keep the second diffracted light irradiating the sample with a larger energy.

[0034] In one possible design, the light source includes a microlaser.

[0035] By utilizing the above technical solution, a light source with high coherence can be ensured.

[0036] The present application also provides a lensless microscopic imaging method, based on the above-mentioned lensless microscopic imaging device, comprising:

[0037] The light source emits laser light;

[0038] The coupling-in grating causes the laser to diffract once to form a first diffracted light, and the first diffracted light enters the optical waveguide at the coupling-in grating;

[0039] The optical waveguide transmits the first diffracted light to the outcoupling grating, the outcoupling grating causes the first diffracted light to undergo secondary diffraction to form second diffracted light, and the second diffracted light is guided out of the optical waveguide;

[0040] The second diffraction light of multiple diffraction orders illuminates the sample on the slide, and the image sensor obtains coaxial holograms of the sample at multiple viewing angles by means of transmission coaxial holography.

[0041] The lensless microscopic imaging method of the present application has at least the following technical effects: the laser emitted by the light source is diffracted once by the coupling grating to form the first diffracted light, and the first diffracted light is introduced into the optical waveguide, so that the first diffracted light propagates from the first end to the second end in the optical waveguide, and the first diffracted light is diffracted twice by the coupling grating to form the second diffracted light, and the second diffracted light is led out of the optical waveguide at the coupling grating, thereby converting the axial propagation between the light source and the sample into the lateral propagation along the length direction of the optical waveguide, thereby compressing the axial distance between the light source and the sample. At the same time, the multi-order diffracted light is led out from the lead-out grating and irradiated onto the sample, and the second diffracted light at multiple different angles is used to illuminate the sample at the same time, so that the image sensor can form a coaxial hologram carrying the sample information, and realize multi-view coaxial holographic microscopic imaging. In addition, the first diffracted light and the second diffracted light can retain the coherence of the laser emitted by the light source, thereby realizing high-coherence lensless holographic three-dimensional microscopic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 is a schematic structural diagram of a device provided by an embodiment of the present application from one perspective;

[0044] Figure 2 It is a schematic diagram of the diffraction principle of laser light of a device provided by an embodiment of the present application;

[0045] Figure 3 is a schematic diagram of a diffraction principle of a first diffracted light of a device provided by an embodiment of the present application;

[0046] Figure 4 is another diffraction principle schematic diagram of the first diffracted light of the device provided by one embodiment of the present application;

[0047] Figure 5 A schematic diagram of the diffraction angle of the second diffracted light of the device provided in one embodiment of the present application;

[0048] Figure 6 This is a flowchart of three-dimensional reconstruction based on multi-view holograms of the device of this application.

[0049] Description of main reference numerals:

[0050] 100 - light source, 200 - coupling-in grating, 300 - optical waveguide, 400 - coupling-out grating, 500 - image sensor, 600 - glass slide, 700 - housing, 710 - first transparent window, 720 - second transparent window, 730 - first cavity, 740 - second cavity, 750 - third cavity. DETAILED DESCRIPTION

[0051] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0052] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0053] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] In order to illustrate the technical solution described in this application, a detailed description is given below in conjunction with specific drawings and embodiments.

[0056] Reference Figures 1 to 6 As shown, an embodiment of the present application provides a lensless microscopic imaging device, which includes a light source 100, an in-coupling grating 200, an optical waveguide 300, an out-coupling grating 400, and an image sensor 500. The light source 100 is used to emit laser light. The in-coupling grating 200 is arranged opposite to the light source 100, and the in-coupling grating 200 is used to cause the laser light to diffract once to form a first diffracted light. The optical waveguide 300 has a first end and a second end that are arranged opposite to each other. The in-coupling grating 200 is arranged at a position close to the first end of the optical waveguide 300, and the in-coupling grating 200 can guide the first diffracted light into the optical waveguide 300, and the optical waveguide 300 is used to propagate the first diffracted light from the first end to the second end. The out-coupling grating 400 is arranged at a position close to the second end of the optical waveguide 300, and the out-coupling grating 400 is used to cause the first diffracted light to diffract twice to form a second diffracted light, and to guide the second diffracted light out of the optical waveguide 300. The image sensor 500 is arranged opposite to the outcoupling grating 400 , and the image sensor 500 is used to form a coaxial hologram carrying sample information under the illumination of the secondary diffraction light.

[0057] In some specific embodiments, the optical waveguide 300 is in the shape of a cuboid, and the optical waveguide 300 has an upper side surface and a lower side surface that are arranged opposite to each other, the left end of the optical waveguide 300 is the first end, and the right end of the optical waveguide 300 is the second end. The coupling-in grating 200 is arranged on the upper side surface of the optical waveguide 300 near the first end or on the lower side surface of the optical waveguide 300 near the first end. The coupling-out grating 400 is arranged on the upper side surface of the optical waveguide 300 near the second end or on the lower side surface of the optical waveguide 300 near the second end.

[0058] In some specific embodiments, the coupling-in grating 200 and the coupling-out grating 400 are disposed on the same side of the optical waveguide 300. For example, the coupling-in grating 200 is disposed on the lower side of the optical waveguide 300, the light source 100 is disposed below the coupling-in grating 200, and the light source 100 is opposite to the coupling-in grating 200; the coupling-out grating 400 is disposed on the lower side of the optical waveguide 300, the image sensor 500 is disposed below the coupling-out grating 400, and the image sensor 500 is opposite to the coupling-out grating 400. For another example, the coupling-in grating 200 is disposed on the upper side of the optical waveguide 300, the light source 100 is disposed above the coupling-in grating 200, and the light source 100 is opposite to the coupling-in grating 200; the coupling-out grating 400 is disposed on the upper side of the optical waveguide 300, the image sensor 500 is disposed above the coupling-out grating 400, and the image sensor 500 is opposite to the coupling-out grating 400.

[0059] In some specific embodiments, the coupling-in grating 200 and the coupling-out grating 400 are respectively disposed on different sides of the optical waveguide 300. For example, the coupling-in grating 200 is disposed on the lower side of the optical waveguide 300, the light source 100 is disposed below the coupling-in grating 200, and the light source 100 is opposite to the coupling-in grating 200; the coupling-out grating 400 is disposed on the upper side of the optical waveguide 300, the image sensor 500 is disposed above the coupling-out grating 400, and the image sensor 500 is opposite to the coupling-out grating 400. For another example, the coupling-in grating 200 is disposed on the upper side of the optical waveguide 300, the light source 100 is disposed above the coupling-in grating 200, and the light source 100 is opposite to the coupling-in grating 200; the coupling-out grating 400 is disposed on the lower side of the optical waveguide 300, the image sensor 500 is disposed below the coupling-out grating 400, and the image sensor 500 is opposite to the coupling-out grating 400.

[0060] When the device of the above embodiment is used to image the sample, the sample is placed between the outcoupling grating 400 and the image sensor 500. The second diffraction light diffracted from the outcoupling grating 400 can illuminate the sample and the image sensor 500, and a hologram carrying the sample information is formed on the image sensor 500 through transmission coaxial holographic imaging.

[0061] By utilizing the technical solutions of some of the above-mentioned embodiments, the laser emitted by the light source 100 is diffracted once by coupling in the grating 200 to form a first diffracted light, and the first diffracted light is introduced into the optical waveguide 300. The optical waveguide 300 serves as a propagation medium for the first diffracted light. The first diffracted light is propagated from the first end to the second end after multiple reflections along the light reflection path in the optical waveguide 300. The first diffracted light is diffracted twice by the coupling-out grating 400 to form a second diffracted light. The second diffracted light is guided out of the optical waveguide 300 at the coupling-out grating 400, thereby converting the long-distance axial propagation between the light source 100 and the sample into the lateral propagation along the length direction of the optical waveguide 300, thereby reducing the axial distance between the light source 100 and the sample, and further reducing the axial thickness of the imaging device. At the same time, through the multi-order diffraction effect of the import grating and the export grating, the multi-order diffraction light is exported from the export grating and irradiated onto the sample, and the sample is illuminated simultaneously by the second diffraction light of multiple different angles. Under the irradiation of the second diffraction light, the image sensor 500 forms a coaxial hologram carrying sample information, realizing multi-view coaxial holographic microscopic imaging. In addition, the first diffraction light and the second diffraction light can retain the coherence of the laser emitted by the light source 100, thereby realizing high-coherence lensless holographic three-dimensional microscopic imaging.

[0062] Reference Figure 1 As shown, in some embodiments, the light source 100 and the image sensor 500 are disposed on the same side of the optical waveguide 300. In some specific embodiments, the light source 100 and the image sensor 500 are disposed below the optical waveguide 300, and correspondingly, the coupling-in grating 200 is located directly above the light source 100, and the light source 100 can emit laser light to the coupling-in grating 200. The coupling-out grating 400 is located directly above the image sensor 500, and the second diffracted light diffracted from the coupling-out grating 400 can illuminate the image sensor 500.

[0063] By utilizing the above technical solution, the light source 100 and the image sensor 500 are arranged on the same side of the optical waveguide 300, so that the structure of the light source 100, the optical waveguide 300 and the image sensor 500 is made more compact, thereby reducing the axial distance between the light source 100, the optical waveguide 300 and the image sensor 500 and reducing the axial thickness of the imaging device.

[0064] Reference Figure 1 As shown, in some embodiments, the light source 100 emits laser light in a first direction, and the first direction is perpendicular to the plane where the coupling-in grating 200 is located. By using the technical solutions of some of the above embodiments, by making the light source 100 emit laser light in a direction perpendicular to the plane where the coupling-in grating 200 is located, it is ensured that the diffracted lights of various levels diffracted from the right side of the normal line can have greater energy.

[0065] Reference Figure 1As shown, in some embodiments, the lensless microscopic imaging device further includes a glass slide 600, which is disposed between the out-coupling grating 400 and the image sensor 500, and the glass slide 600 is parallel to the plane where the out-coupling grating 400 is located. In some specific embodiments, the glass slide 600 is a rectangular glass slide, and the sample is placed on the upper surface of the glass slide 600. The area of ​​the upper surface of the glass slide 600 is the effective area of ​​the glass slide 600, the lower surface of the out-coupling grating 400 is the effective area of ​​the in-coupling grating 200, and the upper surface of the image sensor 500 is the effective area of ​​the sensor. In some embodiments, the effective area of ​​the glass slide 600 is smaller than the effective area of ​​the out-coupling grating 400, and the effective area of ​​the out-coupling grating 400 is equal to the effective area of ​​the image sensor 500. In some embodiments, the effective area of ​​the glass slide 600 is equal to the effective area of ​​the out-coupling grating 400, and the effective area of ​​the out-coupling grating 400 is equal to the effective area of ​​the image sensor 500. This ensures that the sample at any position on the glass slide 600 can be illuminated by the second diffracted light diffracted from the outcoupling grating 400 , thereby improving the imaging quality of the image sensor 500 .

[0066] By using the technical solutions of some of the above embodiments, by arranging a glass slide 600 between the outcoupling grating 400 and the image sensor 500, and placing the sample on the glass slide 600, the second diffraction lights of multiple diffraction orders derived from the outcoupling grating 400 can be respectively irradiated on the glass slide 600, thereby directly forming a hologram carrying sample information on the image sensor 500 in a transmission coaxial holographic manner. By making the glass slide 600 parallel to the plane where the outcoupling grating 400 is located, the diffraction lights of multiple diffraction orders derived from the outcoupling grating 400 can maintain a large energy and irradiate the sample.

[0067] Reference Figure 1As shown, in some embodiments, the lensless microscopic imaging device also includes a housing 700, the light source 100, the optical waveguide 300, and the image sensor 500 are all arranged in the housing 700, a first transparent window 710 is arranged at a position of the housing 700 opposite to the outcoupling grating 400, a second transparent window 720 is arranged at a position of the housing 700 opposite to the image sensor 500, the first transparent window 710 and the second transparent window 720 are arranged opposite to each other, and the glass slide 600 is arranged on the second transparent window 720. In some embodiments, the shell 700 is a box structure, and at least two partitions are arranged in the shell 700, namely a first partition and a second partition, wherein the first partition is installed at a position close to the inner top wall of the shell 700, and the second partition is installed at a position close to the inner bottom wall of the shell 700, the light source 100 and the optical waveguide 300 are arranged between the inner top wall of the shell 700 and the first partition, the image sensor 500 is arranged between the second partition and the inner bottom wall of the shell 700, the first transparent window 710 is installed on the first partition, the second transparent window 720 is installed on the second partition, the first transparent window 710 is located directly above the second transparent window 720, and the glass slide 600 is arranged on the second transparent window 720.

[0068] By using the technical solutions of some of the above embodiments, the light source 100, the optical waveguide 300, and the image sensor 500 are all arranged in the housing 700, so that the device is more compact. By arranging the first transparent window 710 and the second transparent window 720 on the housing 700, the first transparent window 710 and the second transparent window 720 are arranged opposite to each other, thereby providing an illumination channel for the diffracted light, so that the diffracted light of multiple diffraction orders derived from the coupling grating 400 is respectively irradiated on the glass slide 600, thereby directly forming a hologram carrying sample information on the image sensor 500 in a transmission coaxial holographic manner.

[0069] Reference Figure 1As shown, in some embodiments, the housing 700 is a groove-shaped structure, and a first cavity 730 and a second cavity 740 are formed in the housing 700, and one end of the first cavity 730 and one end of the second cavity 740 are connected to each other through a third cavity 750. The housing 700 includes a first shell, a second shell, and a third shell. The first shell and the second shell are spaced apart to form a groove, and the third shell is disposed on one side of the first shell and the second shell. The first cavity 730 is formed in the first shell, the second cavity 740 is formed in the second shell, and the third cavity 750 is formed in the third shell. The optical waveguide 300 is disposed in the first cavity 730, the image sensor 500 is disposed in the second cavity 740, the light source 100 is disposed in the third cavity 750, the first transparent window 710 is disposed on the cavity wall of the first cavity 730 close to the second cavity 740, and the second transparent window 720 is disposed on the cavity wall of the second cavity 740 close to the first cavity 730. In some specific embodiments, the housing 700 is a rectangular parallelepiped structure with a groove on the right side, and the groove runs through the front wall and the rear wall of the housing 700 along the width direction of the housing 700. The inner upper cavity of the housing 700 is the first cavity 730, the inner lower cavity of the housing 700 is the second cavity 740, and the left cavity of the housing 700 is the third cavity 750. The optical waveguide 300 is arranged in the first cavity 730, and the length direction of the optical waveguide 300 is consistent with the length direction of the housing. The image sensor 500 is arranged in the second cavity 740. The light source 100 is arranged in the third cavity 750, and the laser emitted by the light source 100 is consistent with the height direction of the housing. The first transparent window 710 is arranged on the lower cavity wall of the first cavity 730, and the second transparent window 720 is arranged on the upper cavity wall of the second cavity 740, and the lower cavity wall of the first cavity 730 and the upper cavity wall of the second cavity 740 together constitute the side wall of the groove. When imaging the sample, the glass slide 600 carrying the sample is placed on the upper wall of the second chamber 740 .

[0070] By utilizing the technical solutions of some of the above embodiments, the axial thickness of the housing 700 is effectively reduced, the volume of the device is reduced, and the components of the device are made more compact, which is beneficial to the lightweight design of the device.

[0071] Reference Figure 1 As shown, in some embodiments, the thickness of the housing 700 in the second direction is less than 1 cm, and the second direction is parallel to the height direction of the optical waveguide 300. Reducing the axial thickness of the housing 700 to less than 1 cm effectively reduces the volume of the device, makes the various components of the device more compact, and is conducive to the lightweight design of the device.

[0072] In some embodiments, the angle between the first-order diffracted light diffracted from the side of the normal line of the coupling-in grating 200 close to the coupling-out grating 400 and the normal line is the diffraction angle of the first-order diffracted light, and the refractive index of the optical waveguide 300 satisfies:

[0073] n2 / n1 <sinθ1=λ / d (1)

[0074] Wherein, n1 is the refractive index of the optical waveguide 300 , n2 is the refractive index of the medium outside the optical waveguide 300 , θ1 is the diffraction angle of the first-order diffracted light, λ is the wavelength of the laser, and d is the grating constant of the coupled-in grating 200 .

[0075] It should be noted that the coupling-in grating 200 has a multi-level diffraction effect, and the angles of the first diffracted lights of each level emitted from the coupling-in grating 200 are based on the following grating equation:

[0076] d(sinθ in ±sinθ out )=m in λ (2)

[0077] Where d is the grating constant, θ is the angle between the first diffracted light and the normal, and θ in is the incident light angle, θ out is the diffraction angle of the first diffracted light, m in is the diffraction order coupled into the grating 200, and λ is the wavelength. in =0) is 0°, that is, parallel to the normal line, which does not meet the condition of total reflection in the waveguide, and therefore cannot be transmitted to the out-coupling grating 400 through the optical waveguide 300. The diffraction light of the coupling-in grating 200 is defined as the positive order on the right side of the normal line, and the diffraction order m that can enter the right optical waveguide 300 is in It can be 1,2,3…

[0078] According to equation (2), the diffraction order m in When θ1 is 1, the corresponding first diffracted light has the minimum diffraction angle, which is expressed as θ1=arcsin(λ / d). By designing the internal refractive index n1 of the optical waveguide 300 and the refractive index n2 of the medium outside the optical waveguide 300, θ1 satisfies the law of total reflection, that is, satisfies the above inequality (1).

[0079] The diffraction angle of the first diffraction light corresponding to a higher diffraction order is larger. Therefore, as long as the diffraction angle of the first diffraction light corresponding to the diffraction order of 1 satisfies inequality (1), the diffraction angle of the first diffraction light corresponding to a higher diffraction order will definitely satisfy inequality (1), that is, the diffraction order m in When 1, 2, 3, ..., the corresponding first diffracted light can be totally reflected in the optical waveguide 300 and propagate to the outcoupling grating 400 .

[0080] Since the energy of the first diffraction light of each level increases with the diffraction order m in Therefore, the diffraction order m is mainly considered. in is 1 and the diffraction order m inSimilarly, the energy of the first diffracted light of each level at the outcoupling grating 400 increases with the diffraction order m. out The absolute value of the diffraction order m is mainly considered. out is 0, diffraction order m out ±1, diffraction order m out The second diffracted light is ±2. For details, refer to Figure 3 , which shows the diffraction of the second diffracted light when the first diffracted light corresponding to the first diffraction order propagates to the outcoupling grating 400. Figure 4 , which shows the diffraction condition of the second diffraction light when the first diffraction light corresponding to the second diffraction order propagates to the outcoupling grating 400 .

[0081] The outgoing grating 400 uses the same grating constant d as the incoming grating 200, and defines the angle of the outgoing light on the right side of the normal as positive. in When m is 1, out The angles corresponding to the five diffraction orders of 2, 1, 0, -1, and -2 are -θ1, 0°, θ1, θ2, and θ3 respectively; for m in =2, m out The angles corresponding to the five diffraction orders of 2, 1, 0, -1, and -2 are 0°, θ1, θ2, θ3, and θ4, respectively. These angles are obtained by the following formula:

[0082] θ p =arcsin(pλ / d),p=1,2,3,4... (3)

[0083] Regardless of the coupling-in grating 200 or the coupling-out grating 400, the energy of the diffracted light at each level decreases as the diffraction order increases. Therefore, among the diffracted light at each angle emitted by the coupling-out grating 400, the light emitted at the three angles of 0°, θ1, and θ2 has the largest light intensity. Figure 5 After the emitted light at these three angles illuminates a certain sample, multiple holograms of the sample at different viewing angles are formed on the camera sensor, providing a data basis for subsequent three-dimensional reconstruction.

[0084] The image sensor 500 records the hologram and imports it into the back-end module through the data line. Through the calculation of the back-end module, the three-dimensional amplitude, phase, and morphology of the sample are inverted and reconstructed. The back-end module includes a power supply module, a control module, and a processing module. The power supply module realizes the power supply to the light source 100 and the image sensor 500, and the control module and the processing module realize the three-dimensional reconstruction of the sample.

[0085] By utilizing the technical solutions of some of the above embodiments, all positive-order diffracted lights can be totally reflected in the optical waveguide 300, effectively increasing the energy of the first diffracted light totally reflected in the optical waveguide 300, so as to keep the second diffracted light irradiating the sample with a larger energy.

[0086] In some embodiments, the light source 100 includes a micro laser. The micro laser includes one or more of a vertical cavity surface emitting laser and a laser diode. In some specific embodiments, the micro laser is a vertical cavity surface emitting laser, and in some specific embodiments, the micro laser is a laser diode. Such an arrangement can ensure high coherence of the laser, the first diffracted light, and the second diffracted light emitted by the light source 100.

[0087] The present application also provides a lensless microscopic imaging method, based on the above-mentioned lensless microscopic imaging device, including: a light source 100 emits laser light; an in-coupling grating 200 causes the laser light to diffract once to form a first diffracted light, and the first diffracted light enters an optical waveguide 300 at the in-coupling grating 200; the optical waveguide 300 transmits the first diffracted light to an out-coupling grating 400, and the out-coupling grating 400 causes the first diffracted light to diffract twice to form a second diffracted light, and the second diffracted light is derived from the optical waveguide 300; the second diffracted light of multiple diffraction orders irradiates the sample on the slide 600, and the image sensor 500 obtains the coaxial holograms of the sample at multiple viewing angles by means of transmission coaxial holography. The multi-view hologram of the sample serves as an information source for realizing three-dimensional reconstruction of the sample, and provides a data basis for subsequent three-dimensional reconstruction.

[0088] Reference Figure 6 As shown, the three-dimensional reconstruction includes: reconstructing the multi-perspective hologram into a multi-perspective amplitude / phase map; generating amplitude / phase maps of the sample at other virtual perspectives based on the multi-perspective amplitude / phase map; generating the three-dimensional amplitude / phase of the sample through the amplitude / phase maps of all perspectives; and obtaining the three-dimensional morphology of the sample through the three-dimensional amplitude / phase.

[0089] In some embodiments, the three-dimensional reconstruction is implemented by a three-dimensional reconstruction algorithm. In some embodiments, the three-dimensional reconstruction algorithm includes a complex amplitude reconstruction algorithm and a three-dimensional reconstruction algorithm, wherein the complex amplitude reconstruction algorithm and the three-dimensional reconstruction algorithm are in a serial relationship.

[0090] In some embodiments, the complex amplitude reconstruction algorithm reconstructs the multi-perspective hologram into a multi-perspective amplitude / phase map, including perspective 1 (0° illumination), perspective 2 (θ1 illumination), and perspective 3 (θ2 illumination). The complex amplitude reconstruction algorithm in this embodiment mainly refers to a neural network reconstruction algorithm based on a single image. There is no need to collect multiple images at different distances, wavelengths and other parameters. Instead, a multi-perspective amplitude / phase map of the sample is reconstructed using only a single hologram through a trained or untrained neural network. The multi-perspective amplitude / phase map is then input into a three-dimensional reconstruction algorithm. In the three-dimensional reconstruction algorithm, based on the obtained multi-perspective amplitude / phase map, a generative neural network is used to generate amplitude / phase maps under other virtual perspectives, and the three-dimensional amplitude / phase of the sample is reconstructed by integrating all perspectives. The three-dimensional morphology of the sample can be further obtained through the three-dimensional amplitude / phase.

[0091] The lensless microscopic imaging method of the present application has at least the following technical effects: the laser emitted by the light source 100 is diffracted once by the coupling-in grating 200 to form a first diffracted light, and the first diffracted light is introduced into the optical waveguide 300, so that the first diffracted light propagates from the first end to the second end in the optical waveguide 300, and the first diffracted light is diffracted twice by the coupling-out grating 400 to form a second diffracted light, and the second diffracted light is led out of the optical waveguide 300 at the coupling-out grating 400, thereby converting the axial propagation between the light source 100 and the sample into the lateral propagation along the length direction of the optical waveguide 300, thereby reducing the axial distance between the light source 100 and the sample. At the same time, the multi-order diffracted light is led out from the lead-out grating and irradiated onto the sample, and the second diffracted light at multiple different angles is used to illuminate the sample at the same time, so that the image sensor 500 can form a coaxial hologram carrying sample information, and realize multi-view coaxial holographic microscopic imaging. Furthermore, the first diffracted light and the second diffracted light can retain the high coherence of the laser emitted by the light source 100, thereby realizing high-coherence lens-free holographic three-dimensional microscopic imaging.

[0092] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A lensless microscopic imaging device, characterized in that: include: A light source for emitting laser light; A coupling grating, arranged opposite to the light source, for causing the laser to diffract once to form a first diffracted light; An optical waveguide, wherein the optical waveguide has a first end and a second end that are arranged opposite to each other, the coupling-in grating is arranged at a position of the optical waveguide close to the first end, the coupling-in grating can guide the first diffracted light into the optical waveguide, and the optical waveguide is used to propagate the first diffracted light from the first end to the second end; an outcoupling grating, the outcoupling grating being arranged at a position of the optical waveguide close to the second end, and being used for causing the first diffracted light to undergo secondary diffraction to form second diffracted light, and then leading the second diffracted light out of the optical waveguide; The image sensor is arranged opposite to the outcoupling grating, and the image sensor and the outcoupling grating are arranged on the same side of the optical waveguide.

2. The lensless microscopic imaging device according to claim 1, characterized in that: The light source and the image sensor are arranged on the same side of the optical waveguide.

3. The lensless microscopic imaging device according to claim 1, characterized in that: The light source emits the laser along a first direction, and the first direction is perpendicular to the plane where the coupling-in grating is located.

4. The lensless microscopic imaging device according to claim 1, characterized in that: It also includes a glass slide, which is arranged between the out-coupling grating and the image sensor, and is parallel to the plane where the out-coupling grating is located.

5. The lensless microscopic imaging device according to claim 4, characterized in that: It also includes a shell, the light source, the optical waveguide, and the image sensor are all arranged in the shell, a first transparent window is arranged at a position of the shell opposite to the outcoupling grating, a second transparent window is arranged at a position of the shell opposite to the image sensor, the first transparent window is arranged opposite to the second transparent window, and the glass slide is arranged on the second transparent window.

6. The lensless microscopic imaging device according to claim 5, characterized in that: The housing is a groove-shaped structure, comprising a first shell, a second shell and a third shell, the first shell and the second shell are spaced apart to form a groove, the third shell is arranged on one side of the first shell and the second shell, a first cavity is formed in the first shell, a second cavity is formed in the second shell, and a third cavity is formed in the third shell, the first cavity is arranged opposite to the second cavity, and one end of the first cavity and one end of the second cavity are connected to each other through the third cavity; The optical waveguide is arranged in the first cavity, the image sensor is arranged in the second cavity, the light source is arranged in the third cavity, the first transparent window is arranged on the cavity wall of the first cavity close to the second cavity, and the second transparent window is arranged on the cavity wall of the second cavity close to the first cavity.

7. The lensless microscopic imaging device according to claim 5, characterized in that: The thickness of the housing in the second direction is no more than 1.5 cm, and the second direction is parallel to the height direction of the optical waveguide.

8. The lensless microscopic imaging device according to claim 7, characterized in that: The thickness of the shell in the second direction is less than 1 cm.

9. The lensless microscopic imaging device according to claim 1, characterized in that: The angle between the first-order diffracted light diffracted from the side of the normal line of the coupling-in grating close to the coupling-out grating and the normal line is the diffraction angle of the first-order diffracted light, and the refractive index of the optical waveguide satisfies: n2 / n1 <sinθ1=λ / d Wherein, n1 is the refractive index of the optical waveguide, n2 is the refractive index of the medium outside the optical waveguide, θ1 is the diffraction angle of the first-order diffracted light, λ is the wavelength of the laser, and d is the grating constant of the coupling grating.

10. The lensless microscopic imaging device according to claim 1, characterized in that: The light source includes a microlaser.

Images