Super wide field, large depth of field superlens assembly for microscopic endoscopy

Abstract

A pair of metasurfaces is used in the microendoscope to provide imaging within a 172° field of view with a depth of focus extending from 0.3 mm to >300 mm. The operating wavelength range can be from 450 nm to 1550 nm. The resolution of the microendoscope can be up to 115 line pairs / mm. The size of the meta-optical imager of the microendoscope can be as small as approximately 1 mm × 1 mm × 1 mm.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Application No. 63 / 626,926, filed January 30, 2024, pursuant to 35 USC 119(e), the entire contents of which are incorporated herein by reference for all purposes. Background Technology

[0003] The human body contains several narrow and / or tortuous anatomical structures that are difficult to reach and image using conventional endoscopes. These structures include tissues and organs that can be monitored for early cancer detection (such as the lungs, ovaries, and pancreas), cerebral arteries (for assessing cardiovascular risk), or the fetus (which needs to be observed during prenatal surgery). Optical probes that enable surgeons to perform better in-situ imaging and analysis of problems will significantly improve the specificity and sensitivity of screening procedures (e.g., cancer screening) or guide surgical procedures (e.g., treatment of cerebral aneurysms).

[0004] Various miniaturized endoscopes have been developed to facilitate access to such areas while minimizing trauma. These endoscopes include fiber optic bundles, spectrally encoded endoscopes, scanning fiber optic endoscopes, and advanced chip-based endoscopes. However, apart from advanced chip-based endoscopes, these other endoscopes are not yet widely used by clinicians. Currently, many surgeons still rely on demanding ex vivo bright-field microscopy of biopsy samples for diagnosis. Summary of the Invention

[0005] Due to considerations of sterility and cost, disposable microendoscopes providing high-resolution wide field-of-view (WFOV) imaging would benefit clinicians and researchers in the medical field. This article describes a microendoscope that uses a meta-optical imager (comprising two metasurfaces spaced apart) and a deconvolution process to produce WFOV images with high resolution (up to 115 line pairs / mm) (FOV up to 172 degrees). The depth of focus (DOF) of the meta-optical imager can range from 0.3 mm to at least 300 mm. The imaging optics may not include conventional lenses (such as compound lenses) but instead comprise two metasurfaces formed on opposite sides of a flat substrate or on the flat surfaces of two substrates using conventional photolithography processes. Therefore, the imaging optics can be low-cost and disposable. Furthermore, in some embodiments, the size of the meta-optical imager may not exceed 1 cubic millimeter.

[0006] Some embodiments relate to a microendoscopy comprising: a wide-field metalens including a first plurality of metaatoms disposed on a first surface; an aperture including an opening in a light-blocking material layer disposed on a second surface spaced from the first surface, the aperture being arranged to limit the spatial extent of light received by the wide-field metalens; and an extended depth-of-focus metaoptics including a second plurality of metaatoms disposed on the second surface in the opening of the aperture, wherein the second plurality of metaatoms are arranged across the opening to impart a phase profile to light passing through the opening and incident on the wide-field metalens.

[0007] Some implementations relate to a method for imaging using a microendoscopy. The method may include the following actions: receiving light with wavelengths in the range of 450 nm to 1550 nm passing through an opening in a field of view, the field of view having an angle of at least 160 degrees; imparting a phase profile to the light using an extended depth-of-focus meta-optics disposed in the opening; receiving the light from the extended depth-of-focus meta-optics using a wide field-of-view meta-lens; recording raw image data at the image plane of the wide field-of-view meta-lens using an imaging array; and deconvolving the raw image data using at least one point spread function (PSF) corresponding to the phase profile imparted by the extended depth-of-focus meta-optics to generate an image of the object in the field of view.

[0008] All combinations of the concepts described above and other concepts discussed in more detail below (provided that such concepts do not contradict each other) constitute part of the inventive subject matter disclosed herein. In particular, all combinations of the subject matter appearing in this disclosure are part of the inventive subject matter disclosed herein. Terms used herein that may also appear in any disclosure incorporated by reference should be given the meaning most consistent with the specific concepts disclosed herein. Attached Figure Description

[0009] Those skilled in the art will understand that the accompanying drawings are primarily for illustrative purposes and are not intended to limit the scope of the subject matter of the invention described herein. The drawings are not necessarily drawn to scale; in some cases, various aspects of the subject matter disclosed herein may be exaggerated or enlarged in the drawings to facilitate understanding of different features. In the drawings, similar reference numerals generally refer to similar features (e.g., functionally and / or structurally similar elements).

[0010] Figure 1 A portion of a metasurface is depicted, which has multiple metaatoms disposed on the surface of a planar substrate.

[0011] Figure 2A An exemplary structure of a meta-optical imager that can be realized in a micro-endoscope is depicted.

[0012] Figure 2B An exemplary embodiment of an optical assembly for a microendoscopy is depicted, the optical assembly comprising two meta-optical devices located on a substrate.

[0013] Figure 2C An exemplary embodiment of an optical assembly is described, comprising two meta-optical devices located on two substrates that can be combined for use in a microendoscopy.

[0014] Figure 3A A cubic phase diagram of the extended depth-of-focus meta-optical device was drawn.

[0015] Figure 3B The point spread functions (PSFs) of several different cubic extended depth-of-focus meta-optical devices, calculated through numerical simulation, are plotted.

[0016] Figure 3C The measured PSF values ​​generated by the cubic extended depth-of-focus meta-optics are shown, in comparison with... Figure 3B The simulation was compared. The grayscale in the image has been inverted.

[0017] Figure 4A The PSF of the logarithmic aspherical extended depth-of-focus meta-optical device, calculated through numerical simulation, is plotted.

[0018] Figure 4B The measured PSF (grayscale inversion) produced by the log-aspheric extended depth-of-focus meta-optics is shown, in comparison with... Figure 4A The simulations were compared.

[0019] Figure 5A The phase diagram of the shift axis pyramid of the extended depth-of-focus meta-optical device was drawn.

[0020] Figure 5B A spiral phase diagram of the extended depth-of-focus meta-optical device was drawn.

[0021] Figure 6 The steps of the design process for meta-optical devices are described.

[0022] Figure 7 This is a photograph of the meta-optical imager (the black rectangle on the right), and it indicates the size of the imager.

[0023] Figure 8 Drawing out the use of Figure 2A The relationship between deconvolution time and the number of pixels in an image frame is shown in the original image acquired by the meta-optical imager.

[0024] Figure 9A The original image is shown using a meta-optical imager with cubic extended depth of focus meta-optics.

[0025] Figure 9B It shows the result of Figure 9A The deconvolutioned image is generated from the original image.

[0026] Figure 10A The image shows deconvolution (grayscale inversion) images of different line pair groups of a caliper obtained using a meta-optical imager with logarithmic aspherical extended depth of focus meta-optics.

[0027] Figure 10B Showing the target Figure 10A The original image (grayscale inverted) of line pairs grouped at different object distances obtained from the marking board.

[0028] Figure 11 The components of a microendoscopy endoscope with a meta-optical imager at the distal end are described. Detailed Implementation

[0029] 1. Introduction

[0030] When attempting to manufacture small imaging devices with wide FOV, large DOF, and high imaging resolution, the trade-offs between various optical parameters (such as FOV, DOF, and imaging resolution) and the size of the imaging device are particularly challenging. In colonoscopy, providing improved images of the entire colon can increase the detection rate of polyps and adenomas. A 1% increase in adenoma detection can reduce the risk of interphase cancer by 3% and the risk of lethal interphase colorectal cancer by 5%. Therefore, wide FOV imaging systems are desirable for endoscopic imaging, and some conventional systems combine two separate optical components to provide an FOV exceeding 180°. Wide FOV “fisheye” lenses (with an FOV approaching 180°) typically use at least seven cascaded lenses to correct aberrations. Such lens assemblies are almost incompatible with the size requirements of microendoscopy. The axial extension of the imaging system limits the bending radius of the endoscope, restricting its capabilities in surgical settings. Furthermore, wide FOV imaging is typically achieved with a large f-number, which hinders imaging at increased magnification and / or near the endoscope tip.

[0031] In endoscopy, imaging at close range and / or at increased magnification is desirable. Magnifying endoscopy is particularly important for the early detection of small lesions in patients with Barrett's esophagus and those undergoing colorectal cancer screening. Magnifying endoscopy can be enhanced by the local application of staining agents (e.g., magnifying chromoendoscopy). Because endoscopes are often susceptible to unwanted motion, high numerical aperture (NA) imaging typically utilizes extended depth of focus. Some commercial endoscopes include objectives with switchable focus to avoid this problem. An example of such endoscopes is the EVIS X1™, available from Olympus™ Corporation, Americas, Center Valley, PA. However, such endoscopes with extended DOF can be larger and more complex. While a large DOF at low f-numbers theoretically allows for magnified tissue observation without refocusing, existing endoscopes remain too limited in depth of focus to achieve such seamless magnification.

[0032] 2. Overview of Metasurfaces and WFOV Metalenses

[0033] Metasurfaces are engineered optical surfaces that consist of multiple subwavelength three-dimensional structures (called "meta-atoms") patterned across the substrate surface. Figure 1 A portion of a metasurface 110 is depicted, having a plurality of metaatoms 120 disposed on the surface of a substrate 130. The metaatoms can be formed on the surface 130 using microfabrication processes such as photolithography patterning, material deposition, etching, etc. For some applications, the substrate surface 130 and the resulting metasurface 110 may be planar, but in other applications they may be curved or non-planar. The metaatoms 120 may have different shapes and orientations on the metasurface 110. The metaatoms 120 may have any shape (e.g., straight lines, curved or broken lines, rectangles, cylinders, polygons, H-shapes, etc.).

[0034] Figure 1A portion of the metasurface 110 shown is part of a WFOV fisheye lens. Rectangular and H-shaped metaatoms are patterned in lead telluride and disposed on a flat calcium fluoride substrate. These materials were chosen to achieve an operating wavelength of 5.2 micrometers. Other materials and shapes can be used for other operating wavelengths. The WFOV lens, combined with apertures spaced apart from it on the same substrate, achieves diffraction-limited imaging over a FOV range of approximately 170° for the 5.2-micrometer operating wavelength. Further details about the WFOV fisheye lens can be found in “Single-Element Diffraction-Limited Fisheye Metalens,” Shalaginov et al., Nano Lett. 2020, 20, 7429−7437, the full text of which is incorporated herein by reference.

[0035] A large number of meta atoms 120 can exist on the metasurface. The periodicity of the meta atoms 120 can be from about or exactly 150 nm to about or exactly 1 micrometer. In some embodiments, a larger periodicity is used. Therefore, approximately 10 meta atoms 120 can exist per square millimeter on the metasurface. 6 One to nearly 10 8 Each superatom 120. Typically, the filling ratio of the superatom 120 in its unit cell is no greater than 0.8. The height of the superatom 120 can be approximately or exactly 100 nm to 3 micrometers. The superatom 120 can be arranged in a rectangular array (including a square array) or a hexagonal array on the metasurface, but other types of arrays are also possible. A rectangular array is an array in which each superatom 120 is arranged in a rectangular unit cell. Figure 1 A rectangular metaatomic array is a special case where each unit cell is a square. A hexagonal array is an array where each metaatomic atom 120 is arranged in a hexagonal unit cell.

[0036] It should be understood that other materials can be used to form metaatoms and metalenses. Other materials used for metaatoms include, but are not limited to, amorphous silicon, silicon, silicon nitride, high-refractive-index polymers, and titanium oxide. Other metaatom materials include, but are not limited to, various oxides (e.g., tantalum oxide Ta₂O₅, hafnium oxide HfO₂, zirconium oxide ZrO₂), compound semiconductors (e.g., gallium nitride, indium phosphide, etc.). Substrate materials include, but are not limited to, glass, quartz, fused silica, sapphire, and transparent polymers.

[0037] Meta-atoms 120 scatter light incident on meta-surface 110 and form and align them in a predetermined pattern on meta-surface 110 to provide at least one desired optical function for the meta-surface. Examples of desired optical functions include, but are not limited to, focusing incident light over a wide field of view, filtering incident light by wavelength, forming a desired pattern from incident light, and polarizing or acting on the polarization of incident light. In some cases, the meta-surface can be designed to perform optical functions only for a selected polarization of the incident light, without performing optical functions for other polarizations of the incident light. Meta-surfaces provide new ways to efficiently manipulate light and can replace bulky refractive optical components with ultrathin optical components that can be fabricated using microfabrication processes instead of grinding and polishing. Compared to diffractive optical elements, the reduced periodicity of meta-atoms 120 on meta-surface 110 allows for large phase gradients, which is beneficial for realizing lenses with large FOVs. The so-called “planar optics” approach using meta-surfaces can replace the bulky lenses and optical fibers used in conventional endoscopes while improving optical performance. Meta-optics for endoscopes can be engineered to provide aberration correction, increased field of view (FOV), increased depth of field, and more. Furthermore, CMOS fabrication technology can be used to manufacture metasurfaces at low cost compared to conventional bulky optical components.

[0038] The inventors have recognized and understood that the fisheye lens method described above, providing a near 180° WFOV, may be suitable for endoscopic examinations; however, this lens has a limited depth of field, especially at higher numerical apertures. To image points that are not located at or near infinity of the lens, mechanical components are typically used to adjust the distance between the focal plane and the WFOV lens to focus the image. Therefore, the combination of WFOV fisheye lens and aperture is less suitable for high NA imaging in endoscopic applications, where the object being imaged can be located at or near infinity of the lens, as well as close to the lens.

[0039] However, the inventors have also recognized and understood that point spread function (PSF) engineering can significantly extend the DOF of an imaging system and, when combined with image post-processing via deconvolution, eliminate the need for moving parts to image objects located at or near the lens, as well as those close to the lens (e.g., single-shot imaging). In PSF engineering, a desired phase profile is assigned to the light focused by the lens to produce a raw image modulated by that desired phase profile. The raw image can then be deconvolved using the PSF corresponding to the phase profile to produce an image of the object (within the extended DOF) in the system's field of view. In some implementations, the engineered PSF can be designed to eliminate the need for a deconvolution step during imaging, thereby ensuring faster imaging speeds and reducing computational requirements. An example of such a PSF is described below in conjunction with… Figure 4A and Figure 4B Further discussion on logarithmic aspherical PSF.

[0040] 3. Extended Depth-of-Field Meta-Optical Imager

[0041] The inventors have recognized and understood that the phase profile engineered for generating extended depth of field in a PSF can be combined with a focusing lens phase profile, and both phase profiles can be imparted by separate, flat metasurfaces. These two metasurfaces comprise metaatoms disposed on the flat surfaces. In some cases, the two metasurfaces can be disposed on opposite sides of the same substrate. In other embodiments, the two metasurfaces can be patterned on two surfaces of a separate substrate. The two substrates can then be aligned and bonded together.

[0042] The inventors have further recognized and understood that placing an unfocused or weakly focused PSF phase-modulated meta-optical device (which imparts the desired phase profile for extending depth of field) at the aperture position of a fisheye meta-lens, such as Figure 2A The described method imparts a desired PSF-engineered phase wavefront to light passing through a PSF phase-modulated meta-optics device (referred to as "structured light"), thereby significantly increasing the depth of field of the meta-optics and providing suitable imaging quality over a wide field of view. For a given wavelength, this PSF-engineered phase can be imparted in the same or approximately the same manner at all incident angles of light onto the fisheye meta-lens. For each imaging angle, the engineered PSF remains invariant over a wide range of imaging depths. The inventors have also recognized and understood that this extended depth-of-focus (EDOF) phase profile can be imparted at the aperture location to obtain a large depth-of-field imager without introducing distortion to the light incident on the fisheye meta-lens, which would occur if the EDOF meta-optics device were located between or in front of the WFOV meta-lens. Furthermore, if residual angle-dependent wavefront aberrations predictable on the fisheye lens are present, the resulting image can be deconvoluted during post-processing. For example, a proper image can still be reconstructed despite the presence of residual angle-dependent metaatomic responses. The inventors have also recognized and understood that the extended depth-of-focus (EDOF) phase profile imparted by the EDOF meta-optics at the aperture can be used to extend the spectral bandwidth of the optical components, compared to WFOV components with only an aperture.

[0043] In view of the foregoing, the inventors have conceived of a meta-optical imager for microscopic endoscopy. Figure 2AAn example of such a meta-optical imager 200 for a microendoscopy is depicted. The meta-optical imager 200 includes a meta-optical assembly 210 having two meta-surfaces, although more meta-surfaces may be used in some embodiments. The meta-optical assembly 210 includes an aperture 220, a WFOV meta-lens 240, and an EDOF meta-optical device 230 located within the opening of the aperture 220. The meta-optical imager 200 may also include an imaging array 250 (e.g., a CMOS imager) that optically communicates with the meta-optical assembly 210 to acquire raw image data. The meta-optical imager 200 can be highly compact (e.g., occupying no more than 25 mm). 3 The volume, in some cases, is no greater than 10 mm. 3 In some cases, it is no more than 5mm 3 And in some cases, it is no greater than 1mm. 3 And, for example, it can be achieved at the end or head of a microendoscopy or a larger endoscope.

[0044] Aperture 220 includes an opening 222 in the opaque layer 225 and can be formed using a thin metal layer or other light-blocking material. The opening 222 in the light-blocking material can be formed by photolithography (e.g., using photoresist, resist patterning, and etching). In some embodiments, aperture 220 may be disposed on the same surface of the substrate on which the EDOF meta-optical device 230 is disposed, but in some cases it may be formed on another surface. Aperture 220 limits the spatial range (in the x and y directions) of light received by the WFOV meta-lens 240. Light received by the WFOV meta-lens 240 passes through the opening 222 of aperture 220.

[0045] According to some embodiments, the WFOV meta-lens 240 can be implemented as a first meta-surface disposed on opposite surfaces of the same substrate 205, with the EDOF meta-optical device 230 and / or aperture 220 disposed on the same substrate such that the aperture 220 and / or EDOF meta-optical device 230 are spaced from the WFOV meta-lens 240 by a desired distance d. Figure 2B Such implementations are described. In some cases, the EDOF meta-optics 230 can be implemented as a second metasurface on the same substrate 205. The distance d between the WFOV meta-lens 240 and the EDOF meta-optics 230 can be from 0.05 mm to 5 mm. In some cases, the working distance of the meta-optical imager 200 can extend from sub-millimeter to infinity, or in some cases it can be from 0.2 mm to 100 mm. Currently, conventional commercial lens assemblies for endoscopes claim working distances of 3 mm to 80 mm and FOVs limited to 120 degrees, but as discussed above, compared with... Figure 2A and Figure 2BCompared to meta-optical components, this conventional commercial lens assembly includes significantly larger optical components and multiple large optical lenses.

[0046] Figure 2C An embodiment is described in which an EDOF meta-optical device 230 and an aperture 220 are patterned on a first substrate 205-1, and a WFOV meta-lens 240 is patterned on a second substrate 205-2. The patterning and processing of the two meta-optical devices can be performed individually and in parallel. Subsequently, the two meta-optical devices can be aligned with each other, and their substrates 205-1 and 205-2 can be bonded together. The thicknesses of the two substrates can be selected such that when bonded, the EDOF meta-surface and the WFOV meta-surface are spaced by a desired distance d.

[0047] 4. EDOF Meta-optical Elements

[0048] As described above, the EDOF meta-optical device 230 includes metaatoms disposed on a surface spaced apart from the surface on which the WFOV meta-lens 240 is disposed. Light passing through the EDOF meta-optical device 230 has its wavefront across the aperture 220 and the EDOF meta-optical device 230 given a phase profile, which can be defined by the shape and arrangement of the metaatoms on the surface. The EDOF meta-optical device 230 can employ at least four PSF modulation phase profiles. PSF modulation phase profiles can achieve accurate imaging in both the near and far fields. The first PSF modulation phase profile considered by the inventors is a cubic phase profile (which is non-axisymmetric). Figure 3A A phase diagram of the EDOF meta-optics 230 corresponding to the cubic phase profile is depicted. The transition from black to white in the image spans... Range of radians. The cubic phase EDOF meta-optical element 230 is designed to impart such a phase shift to plane waves over the region of aperture 220. The cubic phase profile implemented in the meta-optical imager 200 can provide a near 180° FOV, an extended DOF of 1 mm to 300 mm, and a resolution of up to 50 lp / mm without refocusing. In some embodiments, an efficient back-end deconvolution process can provide an image acquisition frame rate suitable for video displays.

[0049] The cubic phase profile is assigned according to the following equation 1, which describes the phase profile across an aperture of 220:

[0050]

[0051] In this expression, r=0 is located at the center of the aperture opening 222, r 2 =x 2 +y 2R is the radius of the opening in the aperture 220 where the EDOF meta-optical device 230 is located, and α = 1000π. The parameter α has a lower limit of π and can be adjusted to set the distance of the extended depth of focus from the meta-optical component 210. The upper limit is set by the Nyquist sampling criterion. Taking into account the cell size d and the aperture radius R, the Nyquist sampling criterion requires that the phase change Δφ on two adjacent cells be less than π, such that... This translates to an upper limit. A cubic phase profile is an example of an aberration-based phase profile that introduces intentional phase aberrations to change the focus and extend the DOF.

[0052] The cubic PSF modulation phase profile was numerically and experimentally evaluated across a wide range of incident angles. Figure 3B Several different PSFs (Precision Phase Spectra) were calculated through numerical simulations for a point source located at infinity (which generates plane waves incident on the EDOF meta-optics 230 at corresponding angles), at two different depths of focus (3 mm and 10 mm) and different incident angles (0°, 60°, 80°, and 89°). The PSF is generated by light from the point source, which passes through the cubic EDOF meta-optics 230, then through the WFOV meta-lens 240, and finally forms an image on the image plane where the imaging array 250 is located. The peak intensity of each image is located at the center. These plots show the normalized intensity across the image plane located 3 mm and 10 mm behind the EDOF meta-optics 230 as a function of the x and y directions. These plots show that the cubic phase PSF is relatively stable across the incident angle and the 7 mm depth of focus. Figure 3C The measurement results of the PSF generated by the EDOF meta-optical device 230 with a cubic PSF modulated phase profile are shown, for comparison with... Figure 3B The simulations were compared. The recorded original images were not shifted to center the peak intensity and were not... Figure 3B The same horizontal scale was used for plotting. The recorded images are in reasonable agreement with numerical simulations (steady PSF) for incident angle (AOI) variations up to 86 degrees, and the numerical calculations were validated.

[0053] The inventors considered a second phase profile for the EDOF meta-optical device 230: a logarithmic aspherical phase profile (which is axisymmetric). The logarithmic aspherical phase profile imparts a phase profile across the aperture opening according to the following equation 2. Considering parallel incident beams, the logarithmic aspherical phase profile can provide a uniform intensity distribution across the focal line extending between object positions s1 and s2.

[0054]

[0055] In this expression, r=0 is located at the center of the aperture opening 222, and r′ 2 =x 2 +y 2 And R is the radius of the aperture opening 222. To demonstrate the extended depth of focus at high numerical apertures (f / #1.5), the following values ​​can be chosen: s1 = 300 μm and s2 = 1 mm. The logarithmic aspherical phase profile is an example of an axially redistributed phase profile that redistributes light intensity along the propagation axis while maintaining relatively high energy efficiency.

[0056] The logarithmic aspherical PSF modulation phase profile was also numerically and experimentally evaluated. Figure 4A The normalized logarithmic aspherical phase profile (PSF) is shown, calculated from numerical simulations, for a point source located at infinity and for light waves passing through the EDOF meta-optics 230 and the WFOV meta-lens 240. The assigned logarithmic aspherical phase profile produces a PSF with a long, narrow focal spot spanning a distance defined in the design step, in this case, from 400 μm (minimum measurable distance) to 2 mm.

[0057] The EDOF meta-optics 230 is designed to impart a logarithmic aspherical phase profile to the incident plane wave at an aperture of 220. The EDOF meta-optics is designed to have an elongated focal length over a range of 300 μm to 1 mm, similar to... Figure 4A The simulation conditions. The experimentally measured PSF is shown in... Figure 4B In the middle. For experimental measurements (and Figure 4A (Simulation), the imaging array is located 240,600 micrometers from the WFOV metalens, which in turn is located 230,500 micrometers from the EDOF metaoptics. The illumination wavelength is 940 nm. Figure 4B The measured PSF and Figure 4A The simulated PSF is quite consistent.

[0058] More generally, an EDOF phase profile can be integrated from any of the following series of phase profiles, or any combination of EDOF phase profiles described below and above. The listed phase profiles increase the depth of focus (DOF). The following symbols (and their related meanings) are used in the following expressions: r - radial distance (in polar coordinates); θ - azimuth angle (in polar coordinates); k - wave number, defined as k = 2π / λ, where λ is the wavelength of light; A - constant (amplitude or scaling factor), varying with the phase profile; m - topological charge or integer (for helical phase profiles), related to the phase twist number; B - constant in logarithmic phase profiles, used to control the depth of field; x, y - Cartesian coordinates, - A Zernike polynomial of radial order n and angular order m, used to describe wavefront aberrations; r0 - the reference position in the shift-axis pyramidal phase profile; σ - a parameter used to control the apod width in the apod phase profile; f - focal length (in the context of the FrFT phase profile); α - the fractional order of the Fourier transform (in the context of the FrFT phase profile).

[0059] 4.1. Axial redistribution of phase profile

[0060] The first type of phase profile that can be introduced by the EDOF meta-optics 230 is an axially redistributed phase profile. This type of phase profile redistributes light intensity along the propagation axis while maintaining relatively high energy efficiency. Examples of this type of phase profile are given in this section.

[0061] Logarithmic aspherical phase profile: This distribution improves depth by modifying the phase in a logarithmic manner. This phase profile can also be expressed analytically in the following form, without being bound by any particular theory:

[0062]

[0063] Sinusoidal phase profile: Sinusoidal phase modulation redistributes light along the axis, thereby increasing the depth of focus, and can be expressed analytically in the following form, without being bound by any particular theory:

[0064]

[0065] Exponential phase profile: Exponential phase modulation redistributes light along the axial direction, thereby increasing the depth of focus, and can be expressed analytically in the following form, without being bound by any particular theory:

[0066]

[0067] Tangent phase profile: Tangent phase modulation redistributes light along the axial direction, thereby increasing the depth of focus, and can be expressed analytically in the following form, without being bound by any particular theory:

[0068]

[0069] Square root phase profile: Square root phase modulation redistributes light along the axis, thereby increasing the depth of focus, and can be expressed analytically in the following form, without being bound by any particular theory:

[0070]

[0071] Arcsine phase profile: Arcsine phase modulation redistributes light along the axis, thereby increasing the depth of focus, and can be expressed analytically in the following form, without being bound by any particular theory or coordinate basis:

[0072]

[0073] Displaced Axipyramidal Phase Profile: The axial pyramid produces an extended focal line, while the displacement configuration allows for axial control. The displaced axial pyramid phase profile can be expressed analytically in the following form, without being bound by any particular theory:

[0074]

[0075] Figure 5A A phase diagram depicting the phase profile of the shift-axis pyramid is provided. This phase diagram illustrates the phase shift that will be imparted to the plane wave incident on the EDOF meta-optical device 230.

[0076] Apodized phase profile: A smooth apodization (e.g., a gradually decreasing aperture transmittance) expands the focal point by suppressing diffraction sidelobes and can be expressed by a correlated analytical formula of the following form, without being bound by any particular theory:

[0077]

[0078] Jacobi / Fourier polynomial phase: Additional examples of axially redistributed phase profiles include Jacobi / Fourier polynomial phase profiles of the following forms, without being bound by any particular theory:

[0079]

[0080] 4.2. Aberration-based phase profile

[0081] A second type of phase profile that can be introduced by the EDOF meta-optics 230 is an aberration-based phase profile. This type of phase profile introduces intentional aberrations to modify the focus and extend the DOF. Examples of this type of phase profile are given in this section.

[0082] Cubic phase profile: A cubic phase mask introduces a linear variation in defocus with depth, thereby extending the depth of focus. As described above, a cubic phase mask can be expressed analytically in the following form, without being bound by any particular theory:

[0083]

[0084] Quartic phase profiles: Quartic phase masks extend DOF by introducing higher-order aberrations. Quartic phase profiles can be expressed analytically in the following form, without being bound by any particular theory:

[0085]

[0086] Radial and angular Zernike phase profiles: These phase profiles use Zernike polynomials to control higher-order aberrations, thereby extending the DOF, and can be expressed analytically in the following form, without being bound by any particular theory:

[0087]

[0088] 4.3. Angular redistribution of phase profile

[0089] A third type of phase profile that can be introduced by the EDOF meta-optics 230 is the angular redistribution phase profile. This type of phase profile introduces an angular phase variation, thereby achieving robust propagation and an extended focusing area, and forming a unique beam shape. Examples of this type of phase profile are given in this section.

[0090] Ring-shaped or ring-based phase profiles: These distributions use ring structures to redistribute the focus through angular phase modulation to produce extended depths, such as Bessel-Gaussian phase profiles, and can be expressed analytically without being bound by any particular theory:

[0091]

[0092] Spiral phase profile: This phase profile introduces an azimuth phase shift, thereby producing a vortex beam with increased DOF. The spiral phase profile is designed to generate structured light carrying orbital angular momentum and can be expressed analytically in the following form, without being bound by any particular theory:

[0093]

[0094] The quantity m(r,θ) represents the topological charge. The topological charge can vary with the radial coordinate (r) or azimuth angle (θ), thus enabling dynamic control of the beam characteristics. The target phase profile can involve a linear combination of multiple spiral phase profiles or a combination through other mathematical transformations, thereby allowing for flexible customization of optical vortex characteristics for specific applications. Figure 5B An example of a spiral phase diagram that can be realized in the EDOF meta-optical device 230 is shown.

[0095] Fractional Fourier Transform (FrFT) Phase Profiles: FrFT phase masks modify the optical field through fractional transformation to increase the DOF (Displacement of Light). These phase profiles can be expressed analytically in the following form, without being bound by any particular theory:

[0096]

[0097] 5. Design of Meta-optical Elements

[0098] Meta-optical devices (such as EDOF meta-optical device 230 and WFOV meta-lens 240) can be designed using iterative numerical processes. Figure 6 An overview of the steps involved in the design process 600 of the meta-optics is provided. The design process 600 can begin by identifying (step 605) one or more wavelengths that the meta-optics will use. For this application, the micro-endoscope can operate at one or more wavelengths in the range of approximately or exactly 450 nm to approximately or exactly 1550 nm. Once the wavelength is selected, materials can be selected for the meta-optics (step 610). Typically, materials that exhibit low loss and provide high refractive index contrast at the operating wavelength are selected. For visible wavelengths, example choices of materials for these meta atoms include TiO2, HfO2, ZrO2, GaN, crystalline silicon, and silicon nitride. In the near-infrared, material choices for these meta atoms include crystalline silicon or amorphous silicon, or chalcogenides. As an example of visible radiation at 650 nm, glass (e.g., fused silica) can be selected for the meta-optics substrate 205, and crystalline silicon or another semiconductor material can be selected for the meta atoms 120.

[0099] One or more phase profiles can be selected for the meta-optics (step 615) to obtain the desired optical functionality (or multiple functionality) of the meta-optics. For example, if extended depth of field is desired, a cubic phase profile, a logarithmic aspherical phase profile, a spiral phase profile, or a shift-axis pyramidal phase profile can be selected, examples of which are described above. This phase profile is essentially the phase pattern that imparts to the light waves passing through the meta-optics. If the meta-optics is expected to have more than one functionality (e.g., EDOF and weak focusing), more than one phase profile can be selected and these phase profiles can be superimposed to form the phase profile of the meta-optics. The weak focusing phase profile can be a weak focusing Fresnel lens, such as a weak focusing Fresnel lens that provides focusing capability between 0.01 diopters and 1 diopter. In some cases, such a weak focusing phase profile can be combined with an EDOF phase profile.

[0100] The lattice type (e.g., rectangular or hexagonal) can also be selected by the designer (step 620). Any lattice type can work, and other lattices can also work. A rectangular lattice may be preferred because it is better suited to photolithographic patterning tools that typically generate patterns in Cartesian coordinates.

[0101] Design process 600 may also include selecting the thickness of the metaatoms (step 625). Typically, due to microfabrication process constraints, all metaatoms across the metasurface can have the same thickness. Having all metaatoms with the same thickness simplifies microfabrication process steps. However, in some cases, grayscale lithography can be used to make the metaatoms across the metasurface have different thicknesses. The thickness of the metaatoms can be selected based on the phase profile and the material used. For example, if the maximum phase assigned by the phase profile is θ... max Then the thickness of the metaatomic material can be chosen such that the wave (normal incident angle) propagating through the metaatomic material over the shortest distance receives a value equal to θ. max The phase change is greater than θ max Phase change.

[0102] Once the material, phase profile, lattice type, and metaatom thickness are selected, iterative design of the metasurface can begin. Metasurface design can be performed region-by-region or even metaatom-by-metatom. In this design phase, design process 600 involves selecting the metaatom shape for the metaatom located at position P(x,y) on the metasurface (step 630), then simulating the interaction of this metaatom (surrounded by the same nearest-neighbor metaatoms) with incident light at the design wavelength, and observing the metaatom's response in terms of amplitude and assigned phase.

[0103] The shape of the metaatom 120 at this location can be extracted from a library of metaatom shapes. The shape for each metaatom can be any of the following: cylinder, disk, disk with a central hole, rectangle, rectangle with a central hole, square, square with a central hole, cross, H-shape, I-shape, L-shape, and an n×n grid composed of any of the aforementioned shapes, where n is an integer (e.g., 2, 3, or greater). Manufacturing constraints may limit the value of n, as the grid features in the unit cell will be smaller than the features of a single metaatom. An iterative design process can test each metaatom shape from the library at each location on the metasurface.

[0104] refer to Figure 3A The interaction between light and metaatoms is simulated for each selected location P(x,y) in the metasurface. The simulated location is a unit cell containing the i-th and j-th metaatoms in the metaatomic lattice. Each unit cell containing the metaatoms can be represented as C(i... n , j nThe dimensions of the metaatoms and their neighboring metaatoms used in the simulation can be varied (scaled down to occupy a smaller portion of the unit cell or scaled up) and / or their shapes can be changed to different metaatomic shapes and scaled until the desired phase value at that location is obtained. The periodicity of the lattice can also be varied. The height of the metaatoms can be varied on a unit cell-by-unit-cell basis. If grayscale lithography or nanoimprint lithography is used to pattern the metaatoms, metaatoms of different heights can be fabricated. If the lithography process used to pattern the metaatoms does not allow the height of the metaatoms to be varied on a unit cell-by-unit-cell basis, a global height value can be selected from the different heights simulated. The global height can be the height that provides the minimum amount of phase error considering the response of all metaatoms in the array. The optical interaction between light and the metaatoms and their neighboring metaatoms can be simulated using finite-difference time-domain (FDTD) electromagnetic field solving software and / or strictly coupled-wave analysis (RCWA) software.

[0105] When the desired phase response is achieved, simulations are repeated for variations in the input wave (e.g., variations in incident angle, wavelength, polarization). One goal of these repeated simulations is to find a metaatom shape that provides a stable phase response and transmission value independent of variations in the input wave (steps 640, 650, 660). During this iterative process, the size and / or shape of the metaatom (and its neighboring metaatoms) can be gradually changed (step 660). The shape and size that provide the most stable phase response and transmission value can be selected for this location on the metasurface.

[0106] The iterative process can be repeated until a meta-atom shape is obtained that provides a stable imparted phase and stable transmission value for the input wave range (e.g., a stable phase within ±20 degrees, or within ±10 degrees, or even within ±5 degrees, and a stable transmission value within ±10%, or within ±5%, or even within ±2%). The design process then proceeds (step 654) to the next meta-atom in the lattice (in this example, the lattice index n is incremented), and the iterative process is repeated for the next meta-atom. This process is repeated (e.g., incrementing row-wise or column-wise through each unit cell (steps 652, 654, 656, 658) until the shape and size of all meta-atoms in the lattice are obtained, after which the design process can end (step 670) and a pattern of meta-atoms and the lattice suitable for photolithography can be output. The output pattern can be used for electron beam lithography to pattern metasurfaces on a substrate.

[0107] The design of the WFOV meta-lens 240 may involve determining the phase profile of the WFOV lens. The polynomial of the phase profile can be estimated from optical analysis (e.g., from ray tracing analysis) based on the expected location of the focal point of the WFOV lens and the receiving angle of the WFOV lens. Once this polynomial is found, it can be used to determine the phase profile imparted by the WFOV meta-lens 240. The thickness (or...) of the substrate used for the WFOV lens... Figure 2A The distance d) can be adjusted to provide telecentrism for the meta-optical imager 200, where the principal ray is incident perpendicular to the image plane. Interestingly, separating the EDOF meta-optical element 230 and aperture 220 from the WFOV meta-lens 240 reduces the design burden on the WFOV meta-lens 240. This is because the aperture reduces the reception angle of the WFOV meta-lens 240. The larger reception angle is accommodated by the EDOF meta-optical element 230, which does not require strong focusing.

[0108] 6. Image Restoration

[0109] To reconstruct the scene using the meta-optical imager 200 and a specially engineered PSF, the raw image data generated by the meta-optical imager can be deconvolved using the PSF fabricated from the EDOF meta-optical device 230. Because the PSF is stable over a very wide angular range of the system, a single PSF and a single set of parameters can be used to deconvolve the raw image with acceptable accuracy. Using a single PSF reduces post-processing latency and accelerates image acquisition.

[0110] In one approach, the deconvolution process uses the Wiener filtering algorithm given by the equation (18):

[0111]

[0112] in It is a Wiener filter. It is the Fourier transform of PSF. It is the power spectrum of the signal process, and This is the power spectrum of the noise process. (Ratio) This can be understood as the signal-to-noise ratio (SNR). Using a Wiener filter, the measured data can be expressed using the following expression. Reconstructing the scene :

[0113]

[0114] Numerical simulations were performed to compare deconvolution using a single PSF and deconvolution using multiple incident angle-dependent PSFs. In the first image deconvolution, image data was deconvolved using a single PSF (derived from a point source at 0°) for all incident angles ranging from 0° to 80°. In the second image deconvolution, different PSFs (derived from point sources at 0°, 20°, 40°, 60°, and 80°) were used depending on the incident angle of the light. Some segmentation appeared in the deconvolutioned images when using different PSFs, but otherwise, comparable image quality was observed for both deconvolution processes.

[0115] 7. Exemplary Meta-Optical Imager

[0116] Using similar Figure 2A The meta-optical imager 200 shown acquired several images. Figure 7 An example of such a meta-optical imager 200 is shown. The meta-optical imager 200 is a rectangular structure (small black rectangle) with an aperture opening of 0.2 mm × 0.2 mm and an imaging plane of 1 mm × 1 mm.

[0117] To analyze the meta-optical imager 200, the restored image was obtained using a single PSF (corresponding to either the cubic phase EDOF meta-optical device 230 or the log-aspheric phase EDOF meta-optical device 230). The signal-to-noise ratio (SNR) used for deconvolution of all original images was 0.003. After deconvolution, the contrast of all images was rescaled relative to their maximum contrast to provide contrast continuity for video imaging. The deconvolution and contrast scaling post-processing are crucial for images with… An image with 1664 x 2864 pixels (3664 x 2864 pixels) takes approximately 1.1 seconds to process, and for images with 1664 x 2864 pixels... An image of 500 x 500 pixels takes approximately 44 milliseconds to process. This is because the most advanced chip-based cameras currently available, with a diameter of less than 1 mm, integrate approximately... With a pixel count, the post-processing pipeline of this embodiment of the microendoscopy is almost compatible with video frame rate imaging (41ms per image). Therefore, it has Figure 2A The microendoscopic components can provide clinicians with real-time video (assuming no other significant delays in data acquisition and image display).

[0118] Figure 8 The relationship between post-processing delay and the resolution of the resulting image is plotted. The state-of-the-art 1mm × 1mm cutting-edge chip-type endoscope camera has... It has a number of pixels (indicated by the upward arrow) and is able to acquire and display images within a latency typically allowed for video frame rate imaging (indicated by the horizontal dashed line) (within a much smaller FOV and DOF range). The exemplary microendoscopy of this embodiment (with the same number of pixels and a larger FOV and DOF) has a latency slightly exceeding the currently allowed latency (by less than 10%).

[0119] The inventors have recognized and understand that various methods can be used to accelerate and / or simplify post-processing pipelines. Therefore, hybrid imaging methods combining planar meta-optical elements with efficient image restoration techniques have room for improvement. The inventors have also recognized that some meta-optical element designs do not require computational reconstruction for image restoration. Instead, the quality of the original image may be sufficient for image analysis.

[0120] Figure 9A A set of raw images (line pairs on a 1951 USAF datum plate) acquired at different distances from the endoscope aperture 220 using the micro-endoscope of this embodiment are shown. The endoscope uses a cubic PSF modulated phase EDOF meta-optical device 230. Figure 9B It shows the corresponding Figure 9A The deconvolutioned image is generated from the target image. The distance to the target decreases from left to right, from 75mm to 1mm. The imaging resolution can be as fine as 50 line pairs / mm.

[0121] The inventors have discovered that log-aspheric PSFs may have two advantages over cubic PSFs: (1) log-aspheric PSFs are rotationally symmetric, which improves the SNR in the final image, and (2) the final image is directly interpretable before deconvolution. The same advantages apply to the third and fourth embodiments of PSF-modulated meta-optics, namely: (1) generating phase profiles of structured light carrying orbital angular momentum, and (2) generating inversely designed phase profiles of PSFs with extended depth of focus.

[0122] Figure 10A It has Figure 2A Imaging results from a microendoscopy device with a meta-optical imager 200, a log-aspheric EDOF meta-optical device 230, and an aperture opening 222 with a diameter of 200 µm. These images were acquired using a CMOS sensor with a pixel size of 1.67 μm × 1.67 μm, allowing image acquisition using only approximately 120 × 120 pixels. The imager is capable of resolving lines spaced approximately 4 μm apart (1951 USAF grading board, group 6, set 6), corresponding to a resolution limit of approximately 115 lp / mm. Figure 10B As shown, the focus remains stable within a distance range of 400μm to 1.5mm. Figure 10BThe images were obtained without any post-processing, demonstrating that the original images are recognizable for log-aspheric phase profiles without deconvolution. The resolution of the imager may be limited by the pixel size of the imaging array 250, rather than by the meta-optical components 210.

[0123] Polarization multiplexing provides a way to embed the above-described features into a single imaging device. Figure 9A (PSF associated with cubic phase profile) and Figure 10A This involves two complementary approaches to the PSF (Phase Filtering) associated with a log-aspheric phase profile. For example, the metaatoms of the EDOF meta-optics 230 can be designed to provide a first phase profile (e.g., cubic phase) for a first polarization state of light and a second phase profile (e.g., log-aspheric) for a second polarization state of light incident on the EDOF meta-optics 230. In such cases, the EDOF can be further enhanced (by selecting polarization) without requiring refocusing in the endoscope or replacement of optics.

[0124] Color imaging makes endoscopes more suitable for widespread use. Because the refractive index varies with wavelength, chromatic aberration may exist in the meta-optical imager 200 when imaging across the entire visible wavelength band. For example, image size and / or image position may differ for different color bands (red, green, blue). To compensate for chromatic aberration during color imaging, different PSFs can be used to deconvolve the recorded image for different color bands (wavelength ranges). For example, a first PSF can be used to deconvolve the image obtained from red pixels (corresponding to red wavelengths), a second different PSF can be used to deconvolve the image obtained from green pixels (corresponding to green wavelengths), and a third different PSF can be used to deconvolve the image obtained from blue pixels (corresponding to blue wavelengths). Different PSFs can be calculated or measured from the meta-optical component 210 for the center wavelength in each color band.

[0125] The inventors also recognized that the telecentric architecture of the two-layer EDOF and WFOV is suitable for full-color imaging applications. For example, during the design phase, phase stability can be further studied under wavelength variations across part or all of the visible region. If the metaatoms produce stable phase profiles within a certain wavelength range, deconvolution with different PSFs may not be necessary.

[0126] Figure 11A microendoscopic system 900 is depicted, comprising a meta-optical imager 200 disposed in an endoscope lens section 910. The microendoscopic system 900 includes the endoscope lens section 910, a flexible cable 920, a controller 930, and a display 940 (e.g., an LED display screen) for displaying images acquired by the system. The endoscope lens section 910 may include an aperture 220, an EDOF meta-optical element 230, and a WFOV meta-lens 240, examples of which have been described above. In some cases, the opening of the aperture 220 may have a radius in the range of 50 μm to 500 μm, or in some cases, a radius in the range of 25 μm to 100 μm. The EDOF meta-optical element 230 may be disposed within the opening of the aperture 220. In some cases, the WFOV meta-lens 240 may be disposed on a first surface of the substrate, and the aperture 220 and the EDOF meta-optical device 230 may be disposed on a second surface of the same substrate, which is located on the side of the substrate opposite to the first surface (e.g., on both surfaces of an optical plate).

[0127] The endoscope lens unit 910 may also include an imaging array 250, which, in conjunction with the above description, Figure 2A The description is as follows. Imaging array 250 may be located at the image plane of WFOV meta-lens 240 to record raw images of objects in the field of view of the endoscope section. The field of view may have an angle of at least 160 degrees. In some embodiments, aperture 220, EDOF meta-optics 230, and WFOV meta-lens 240 may be arranged within the endoscope section 910 at a distance not exceeding 5 mm. 3 Within its volume. The endoscope section 910 may be located at the distal end of the flexible cable 920, away from the controller 930. Data from the imaging array 250 may be transmitted to the controller 930 via the flexible cable 920.

[0128] The flexible cable 920 may include one or more conductive wires for powering and communicating with the imaging array 250 (e.g., receiving image data from the imaging array). An endoscope portion 910 may be mounted on the distal end of the flexible cable 920, and the flexible cable 920 may have an external polymer sheath.

[0129] A flexible cable 920 can be connected to a controller 930, which receives and processes data from the imaging array 250 in the endoscope lens section 910. The controller 930 may include processing circuitry at least in part for deconvolving the raw image and generating a resulting image for display on a display 940. Examples of components that may be included in the processing circuitry of the controller 930 include, but are not limited to, microprocessors, microcontrollers, field-programmable gate arrays (FPGAs), digital signal processors (DSPs), discrete analog circuitry components, digital logic chips, etc.

[0130] Microendoscopy can be implemented and operated in a variety of configurations, some of which are listed below.

[0131] (1) A microendoscopy comprising: a wide field-of-view metalens, the wide field-of-view metalens including a first plurality of meta atoms disposed on a first surface; an aperture including an opening in a light-blocking material layer disposed on a second surface spaced apart from the first surface by a distance d, the aperture being arranged to limit the spatial range of light received by the wide field-of-view metalens; and an extended depth-of-focus (EDOF) metaoptics, the extended depth-of-focus (EDOF) metaoptics including a second plurality of meta atoms disposed on the second surface in the opening of the aperture, wherein the second plurality of meta atoms are arranged across the opening to impart a phase profile to light passing through the opening and incident on the wide field-of-view metalens.

[0132] (2) The micro-endoscope configured as described in (1), wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens includes an axially redistributed phase profile.

[0133] (3) The micro-endoscope as configured in (1) wherein the phase profile imparted by the extended depth-of-focus meta-optics to the light passing through the opening of the aperture to the wide field-of-view meta-lens includes an aberration-based phase profile.

[0134] (4) The micro-endoscope as described in (1) wherein the phase profile imparted by the extended depth-of-focus meta-optics to the light passing through the opening of the aperture to the wide field-of-view meta-lens includes an angularly redistributed phase profile.

[0135] (5) The micro-endoscope as described in (1) wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens is a reverse-designed phase profile that generates a point spread function (PSF) with extended depth of field.

[0136] (6) The microendoscopy as configured in any one of (1) to (5) further comprises: an imaging array arranged at the image plane of the wide field-of-view metalens to record a raw image generated at the image plane by the wide field-of-view metalens and the extended depth-of-focus metaoptics; and a controller communicatively coupled to the imaging array to deconvolve the raw image using a point spread function corresponding to the phase profile imparted by the extended depth-of-focus metaoptics.

[0137] (7) The micro-endoscope as described in (6) further includes: a cable for connecting the controller to the imaging array; and an endoscope portion disposed at the distal end of the cable away from the controller, wherein the wide field-of-view meta-lens, the aperture, the extended depth-of-focus meta-optics and the imaging array are disposed in the endoscope portion.

[0138] (8) A microendoscopy as configured in any one of (1) to (7), wherein the first surface is located on a first side of the substrate and the second surface is located on a second side of the substrate opposite to the first side.

[0139] (9) A microendoscopy configured as described in any one of (1) to (8), wherein the wide field-of-view meta-lens, the aperture and the extended depth-of-focus meta-optics are arranged at a focal length of no more than 25 mm. 3 Within the volume.

[0140] (10) A microendoscopy configured as described in any one of (1) to (9), wherein the opening of the aperture has a radius of less than 500 micrometers.

[0141] (11) A microendoscopy configured as described in any one of (1) to (10), wherein the second plurality of metaatoms are configured to: impart a first phase profile to a first polarization state of the light passing through the opening; and impart a second phase profile to a second polarization state of the light passing through the opening.

[0142] (12) The microendoscopy as configured in (11), wherein the first phase profile is a cubic phase profile and the second phase profile is a logarithmic aspherical phase profile.

[0143] (13) A method for imaging using a microendoscopy, the method comprising: receiving light of wavelength in the range of 450 nm to 1550 nm through an opening in a field of view, the field of view having an angle of at least 160 degrees; imparting a phase profile to the light using an extended depth-of-focus meta-optical device disposed in the opening; receiving the light from the extended depth-of-focus meta-optical device using a wide field-of-view meta-lens; recording raw image data at the image plane of the wide field-of-view meta-lens using an imaging array; and deconvolving the raw image data using at least one point spread function (PSF) corresponding to the phase profile imparted by the extended depth-of-focus meta-optical device to generate an image of the object in the field of view.

[0144] (14) The method as described in (13), wherein assigning the phase profile includes assigning a cubic phase profile to the light.

[0145] (15) The method as described in (13), wherein assigning the phase profile includes assigning a logarithmic aspherical phase profile to the light.

[0146] (16) The method as described in (13), wherein assigning the phase profile includes assigning a phase profile to generate structured light carrying orbital angular momentum.

[0147] (17) The method as described in (13), wherein assigning the phase profile includes assigning a reverse-designed phase profile that generates a PSF with extended depth of field.

[0148] (18) The method of any one of (13) to (17), wherein deconvolution of the original image data comprises deconvolution of the original image data using only one PSF.

[0149] (19) The method of any one of (13) to (17), wherein deconvolution of the original image data comprises: deconvolving the original image data using a first PSF corresponding to the red wavelength range; deconvolving the original image data using a second PSF corresponding to the green wavelength range; and deconvolving the original image data using a third PSF corresponding to the blue wavelength range.

[0150] (20) The method of any one of (13) to (19), wherein applying the phase profile to the light using the extended depth-of-field meta-optics comprises: applying a first phase profile to a first polarization state of the light passing through the opening; and applying a second phase profile to a second polarization state of the light passing through the opening, which is different from the first phase profile.

[0151] 8. Summary

[0152] Although embodiments of the invention have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing the functions described herein and / or obtaining these results and / or one or more of these advantages, and each of such variations and / or modifications is considered to be within the scope of the embodiments of the invention described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on one or more specific applications in which the teachings of the invention are applied. Those skilled in the art will recognize or be able to determine many equivalents of the specific embodiments of the invention described herein using only conventional experimentation. Therefore, it should be understood that the foregoing embodiments are presented by way of example only, and embodiments of the invention may be practiced in ways other than those specifically described. Embodiments of the invention disclosed herein relate to each individual feature, system, article, material, toolkit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials, toolkits, and / or methods is included within the scope of the invention disclosed if it does not contradict each other.

[0153] Furthermore, various inventive concepts may be embodied in one or more methods, examples of which have been provided. Actions performed as part of said method may be ordered in any suitable manner. Therefore, embodiments may be constructed to perform actions in a different order than that shown, and said actions may include performing several actions simultaneously, even if said actions are shown as consecutive actions in the illustrative embodiments.

[0154] All definitions defined and used in this document should be understood as controls over dictionary definitions, definitions incorporated by reference in other documents, and / or the general meaning of the definition terms.

[0155] Unless otherwise stated, the terms "about" and "approximately" are used to indicate within ±20% of the target value (e.g., size or orientation) in some embodiments, within ±10% of the target value in some embodiments, within ±5% of the target value in some embodiments, and within ±2% of the target value in other embodiments. The terms "about" and "approximately" can include the target value. The term "substantially" is used to indicate within ±3% of the target value.

[0156] Unless explicitly indicated otherwise, the indefinite articles “a” and “a kind” used in this article should be understood as meaning “at least one”.

[0157] As used herein, the phrase “and / or” should be understood as meaning “any one or both” of the elements so connected, that is, elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” should be understood in the same way, that is, “one or more” of the elements so joined. Other elements may optionally be present, whether related to or unrelated to those specifically identified by the “and / or” clause. Thus, as a non-limiting example, in one embodiment, when used in conjunction with open-ended language such as “including,” a reference to “A and / or B” may refer only to A (optionally including elements other than B); in another embodiment, only to B (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so on.

[0158] As used herein, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when items in a list are separated, “or” or “and / or” should be interpreted as inclusive, i.e., including many elements or at least one element in a list of elements, but also including more than one element and optionally other items not listed. Only when a term explicitly indicates the opposite meaning (e.g., “only one,” “exactly one,” or “consisting of…”) does it indicate the inclusion of a quantity or exactly one element in a list of elements. In general, when preceded by an exclusive term such as “any one,” “one of…,” “only one of…,” or “exact one of…,” the term “or” as used herein should be interpreted only as indicating an exclusive alternative (i.e., “one or the other, not two”). “Substantially consisting of…” should have its ordinary meaning as used in the field of patent law.

[0159] As used herein, with respect to a list of one or more elements, the phrase "at least one" should be understood as at least one element selected from any one or more elements in the list of elements, but does not necessarily include at least one element from every single element specifically listed in the list of elements, nor exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified within the list of elements referred to by the phrase "at least one," regardless of whether they are related to or unrelated to those specifically identified elements. Thus, as a non-limiting example, in one embodiment, "at least one of A and B" (or equivalently, "at least one of A or B," or equivalently, "at least one of A and / or B") may refer to at least one element that optionally contains more than one A, has no B (and optionally contains elements other than B); in another embodiment, it may refer to at least one element that optionally contains more than one B, has no A (and optionally contains elements other than A); in yet another embodiment, it may refer to at least one element that optionally contains more than one A, and optionally contains more than one B (and optionally contains other elements); and so on.

[0160] In the above description, all transitional phrases, such as “comprising,” “including,” “with,” “having,” “containing,” “involving,” “maintaining,” “consisting of,” etc., should be understood as open-ended, meaning including but not limited to. Only the transitional phrases “consisting of” and “substantially consisting of” should be closed or semi-closed transitional phrases, respectively, as described in Section 2111.03 of the U.S. Patent Examination Procedure Manual.

Claims

1. A microendoscopy system, the microendoscopy system comprising: A wide field-of-view meta-lens, the wide field-of-view meta-lens comprising a first plurality of meta-atoms disposed on a first surface; An aperture, comprising an opening in a light-blocking material layer disposed on a second surface spaced apart from the first surface by a distance d, wherein the aperture is arranged to limit the spatial extent of light received by the wide field-of-view metalens; And an extended depth of focus (EDOF) meta-optical device, the extended depth of focus (EDOF) meta-optical device including a second plurality of meta atoms disposed on a second surface in the opening of the aperture, wherein the second plurality of meta atoms are arranged across the opening to impart a phase profile to light passing through the opening and incident on the wide field of view meta-lens.

2. The microendoscopy of claim 1, wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens includes an axially redistributed phase profile.

3. The microendoscopy of claim 1, wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens includes an aberration-based phase profile.

4. The microendoscopy of claim 1, wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens includes an angularly redistributed phase profile.

5. The microendoscopy of claim 1, wherein the phase profile imparted by the extended depth-of-focus meta-optics to light passing through the opening of the aperture and reaching the wide field-of-view meta-lens is a reverse-designed phase profile that generates a point spread function (PSF) with extended depth of field.

6. The microendoscopy as described in any one of claims 2 to 5, wherein the microendoscopy further comprises: An imaging array is arranged at the image plane of the wide field-of-view meta-lens to record the original image generated by the wide field-of-view meta-lens and the extended depth-of-focus meta-optics at the image plane; A controller, communicatively coupled to the imaging array, deconvolves the original image using a point spread function corresponding to the phase profile imparted by the extended depth-of-focus meta-optics.

7. The microendoscopy as described in claim 6, further comprising: Cables for connecting the controller to the imaging array; The endoscope is disposed at the distal end of the cable away from the controller, wherein the wide field-of-view meta-lens, the aperture, the extended depth-of-focus meta-optics, and the imaging array are disposed in the endoscope.

8. The microendoscopy of claim 1, wherein the first surface is located on a first side of the substrate, and the second surface is located on a second side of the substrate opposite to the first side.

9. The microendoscopy of claim 1, wherein the wide field-of-view metalens, the aperture, and the extended depth-of-focus metaoptical device are arranged within a radius of no more than 25 mm. 3 Within the volume.

10. The microendoscopy of claim 1, wherein the opening of the aperture has a radius of less than 500 micrometers.

11. The microendoscopy of claim 1, wherein the second plurality of metaatoms are configured to: impart a first phase profile to a first polarization state of the light passing through the opening; and impart a second phase profile to a second polarization state of the light passing through the opening.

12. The microendoscopy of claim 11, wherein the first phase profile is a cubic phase profile and the second phase profile is a logarithmic aspherical phase profile.

13. A method for imaging using a microendoscopy, the method comprising: Light with wavelengths in the range of 450 nm to 1550 nm passing through an aperture opening in the field of view is received from an object in the field of view, the field of view having an angle of at least 160 degrees; the light is given a phase profile using an extended depth-of-focus meta-optical device disposed in the aperture; the light is received from the extended depth-of-focus meta-optical device using a wide field-of-view meta-lens; The original image data is recorded at the image plane of the wide field-of-view meta-lens using an imaging array; and the original image data is deconvolved using at least one point spread function (PSF) corresponding to the phase profile imparted by the extended depth-of-focus meta-optics to generate an image of the object in the field of view.

14. The method of claim 13, wherein assigning the phase profile includes assigning a cubic phase profile to the light.

15. The method of claim 13, wherein assigning the phase profile comprises assigning a logarithmic aspherical phase profile to the light.

16. The method of claim 13, wherein assigning the phase profile includes assigning a phase profile for generating structured light carrying orbital angular momentum.

17. The method of claim 13, wherein assigning the phase profile includes assigning a reverse-designed phase profile that generates a PSF with extended depth of field.

18. The method of claim 13, wherein deconvolution of the original image data comprises deconvolution of the original image data using only one PSF.

19. The method of claim 13, wherein deconvolution of the original image data comprises: The original image data is deconvolved using a first PSF corresponding to the red wavelength range; The original image data is deconvolved using a second PSF corresponding to the green wavelength range; and the original image data is deconvolved using a third PSF corresponding to the blue wavelength range.

20. The method of claim 13, wherein assigning the phase profile to the light using the extended depth-of-field meta-optics comprises: Assign a first phase profile to the first polarization state of the light passing through the opening; And to assign a second phase profile, different from the first phase profile, to the second polarization state of the light passing through the opening.

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