Sensor and method for obtaining spectral data from a sensor

Abstract

Provided are a sensor and a method for obtaining spectral data from the sensor. An optical spectrometer can be used to determine the spectral components of electromagnetic waves. Spectrometers can be large, bulky devices, and for recording measurements, the waves may need to enter at nearly right angles. Disclosed is a super-compact spectrometer with nanophotonic components employing optical dispersion techniques. The nanophotonic components can include metasurfaces and Bragg filters. Each metasurface can include light-scattering nanostructures that can be randomized to produce a large input angle, and the Bragg filter can result in optical dispersion independent of the input angle. The spectrometer can be capable of handling a bandwidth of about 200 nm. The super-compact spectrometer can be capable of reading image data within the visible light (400 nm to 600 nm) and capable of reading spectral data within the near-infrared (700 nm to 900 nm) wavelength range. The surface area of the spectrometer can be about 1 mm<supgt;2< / supgt;, making it suitable for mobile devices.

Description

Technical Field

[0001] The subject matter disclosed herein relates to spectrometers. For example, aspects of some example embodiments relate to methods of metasurface construction and fabrication, spectroscopy and imaging, and spectrometer components. Background Art

[0002] Spectroscopy has been a key characterization technique in a variety of scenarios from scientific research to industrial and healthcare applications. A spectrometer can produce spectral lines and can be capable of measuring their wavelengths and intensities. Spectrometers use a dispersive element (such as a diffraction grating or a prism) for achieving wavelength-dependent angular dispersion along with focusing optics that focus the incident light onto a detector. These spectrometers are bulky and have a low angular tolerance (the angular tolerance is the angle at which incident light can enter the spectrometer and spectral analysis can be performed), which limits their use on mobile devices; thus, there is a need for a compact spectrometer with a high angular tolerance.

[0003] The above information disclosed in this background art section is only for enhancing the understanding of the disclosed background art and, thus, it may contain information that does not constitute the prior art. Summary of the Invention

[0004] According to one example embodiment, an image sensor is provided, the image sensor including: an aperture, a dispersion array, a lens, an image sensor, and a processor.

[0005] According to another example embodiment, a method for obtaining spectral data from a sensor is provided, the method including: receiving incident light, scattering the incident light through a scattering layer to produce scattered light, dispersing a subset of the scattered light through a dispersion layer to produce dispersed light, receiving the dispersed light on an image sensor, and reconstructing spectral data based on the dispersed light.

[0006] According to another example embodiment, a dispersion array including at least one dispersion structure is provided, the at least one dispersion structure dispersing light in a target wavelength range starting from 0° (degrees) dispersion of a target wavelength, wherein the dispersion structure further includes: a nanostructure layer and a filter layer.

[0007] According to another example embodiment, a method for manufacturing a dispersion array is provided, the method including: depositing a first filter stack on a substrate, depositing a defect layer, depositing a capping stack, and forming nanostructures in the capping stack. Brief Description of the Drawings

[0008] In the following sections, aspects of the subject matter disclosed herein will be described with reference to example embodiments shown in the drawings, in which:

[0009] Figure 1 Depicts the principle of operation of a spectrometer sensor.

[0010] Figure 2 Depicts the construction of an embodiment of a compact spectrometer.

[0011] Figure 3 Depicts a light dispersion array as viewed from above according to some embodiments of the disclosure.

[0012] Figure 4 Depicts a cross-sectional view of a dispersion structure according to some embodiments of the disclosure.

[0013] Figure 5 Depicts a manufacturing diagram of the formation of layers and nanostructures according to some embodiments of the disclosure.

[0014] Figure 6 Depicts a top view of a dispersion structure according to some embodiments of the disclosure.

[0015] Figure 7 Is a graph depicting the density of nanostructures and the efficiency of their metasurface light dispersion according to some embodiments of the disclosure.

[0016] Figure 8 Depicts a metasurface with nanoantennas according to some embodiments of the disclosure.

[0017] Figure 9 Is a graph depicting the processing of raw data into reconstructed images and spectral components and the efficiency of dispersion at varying wavelengths according to some embodiments of the disclosure.

[0018] Figure 10 Is a graph depicting the angular response of dispersion for selected wavelengths in an exemplary dispersion structure according to some embodiments of the disclosure.

[0019] Figure 11 Depicts an image sensor having two regions of detection pixels according to some embodiments of the disclosure.

[0020] Figure 12 Depicts the processing of raw images into spectral and visible image data according to some embodiments of the disclosure.

[0021] Figure 13 Depicts the manufacturing process of a dispersion structure according to some embodiments of the disclosure. Detailed Description

[0022] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the disclosure. However, those of ordinary skill in the art will understand that the aspects disclosed may be practiced without these specific details. In other instances, well-known methods, steps, components, and circuits have not been described in detail so as not to obscure the subject matter disclosed herein.

[0023] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "according to one embodiment," or other phrases with similar import throughout this specification are not necessarily all referring to the same embodiment. Additionally, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Further, in the context of the discussion herein, a singular term may include the corresponding plural form, and a plural term may include the corresponding singular form.

[0024] It should also be noted that the various figures (including component diagrams) shown and discussed herein are for illustrative purposes only and are not drawn to scale. Similarly, various waveforms and timing diagrams are shown for illustrative purposes only. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Additionally, if deemed appropriate, reference numerals have been repeated in the figures to indicate corresponding and / or similar elements. The terminology used herein is for the purpose of describing some example embodiments only and is not intended to limit the claimed subject matter. As used herein, unless the context clearly dictates otherwise, the singular forms "a," "an," and "the" are also intended to include the plural forms. It will also be understood that when the terms "comprises" and / or "comprising" and their variants are used in this specification, they specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the terms "first," "second," etc. are used as labels for the nouns that follow and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.) unless explicitly defined as such. Additionally, the same reference numerals may be used throughout two or more figures to refer to components, assemblies, blocks, circuits, units, or modules having the same or similar functionality. However, such usage is for simplicity of illustration and convenience of discussion only; it does not mean that the construction or architectural details of such components or units are the same throughout all embodiments or that such commonly referenced components / modules are the only means for implementing some example embodiments disclosed herein.

[0025] It will be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, directly connected to or directly coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, no intervening elements or layers are present. Like reference numerals always refer to like elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will also be understood that terms, such as those defined in a general dictionary, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0027] Figure 1 An example spectrometer 100 is shown. A light source 101 may be provided. The light source 101 may include the visible spectrum and the invisible spectrum, but it may also have a spectrum ranging from far infrared (or lower) to gamma rays. The light source 101 may be used to describe any wavelength mentioned. The light source 101 may come from a thermal solid that emits light (which may or may not be absorbed by an intermediate substance, generating absorption lines), or it may come from an emission spectrum, where the intensity and position of the spectral lines depend on the nature of the emitting substance and the cause of the emission. The input of the light source 101 may be spatial light or from an optical fiber. The light from the light source 101 reaches the entrance slit 102 at an incident light arrival angle 108. Depending on the aperture of the entrance slit 102, the incident light arrival angle 108 can generally be between 0° and 2°.

[0028] The entrance slit 102 may have an aperture in the shape of a square, rectangle or other shape. The optical resolution and throughput of the spectrometer can be determined by the entrance slit 102. The light entering the spectrometer can be focused onto the entrance slit 102, and the entrance slit 102 can be aligned with the light source 101 to allow the light to pass through to other elements. The slit width is generally between 5 μm and 800 μm and the height is generally between 1 mm and 2 mm, but can be other dimensions.

[0029] Once the light source 101 enters the entrance slit 102, it can be reflected on a collimating mirror 103 having a focal length 107, which can be the distance between the entrance slit 102 and the collimating mirror 103. The collimating mirror 103 can be a concave mirror. The collimating mirror 103 collects the light from the light source 101 and directs the light waves parallel to the diffraction grating 104.

[0030] The diffraction grating 104 can separate the light guided by the collimating mirror 103 into different wavelengths, and the different wavelengths can be diffracted at angles specific to each wavelength. These different wavelengths can pass through the diffraction grating 104 or can be reflected away at different diffraction angles. Different transmission gratings can be used for different wavelength ranges. The diffraction grating 104 can be a holographic grating or a ruled grating. A holographic grating can be developed by interfering two ultraviolet light beams on a piece of optical glass, and the holographic grating then produces a sinusoidal refractive index change. A ruled grating can be formed by etching parallel grooves onto the surface of a substrate and then coating the parallel grooves with a reflective material. Ruled gratings may produce more stray light caused by surface defects. The number of grooves per unit length and the groove width in a ruled grating affect the amount of dispersed light. The number of grooves per unit length in a ruled grating can be referred to as the groove frequency or groove density. The wavelength coverage range of the spectrometer having the diffraction grating 104 can be inversely proportional to the density of these grooves.

[0031] Once the light from the light source 101 is dispersed and reflected from the diffraction grating 104, it can reach the focusing mirror 105. The focusing mirror 105 can be concave and focus the light rays onto the image sensor 106. The image sensor 106 can include pixels. The focusing mirror 105 can form an image of the light dispersed into the selected wavelengths. The focusing mirror 105 can reflect the dispersed light into light rays of different wavelengths. Each light ray of varying wavelength can be at a different angle with respect to the diffraction grating 104 and the focusing mirror 105. These light rays can reach the pixels of the image sensor 106, where each pixel receives a different wavelength based on the dispersion angle of the light ray. The image sensor used can depend on the wavelength being measured (including short-wavelength infrared (SWIR), near-infrared (NIR), visible light, ultraviolet (UV), X-rays, etc.). These sensors can be charge-coupled devices (CCD), complementary metal-oxide-semiconductor (CMOS), n-type metal-oxide-semiconductor (NMOS), InGaAs, Si photodiode arrays with amplifiers, photomultiplier tubes (PMT), avalanche photodiodes (APD), or other sensors.

[0032] Light propagating from the diffraction grating 104 can be reflected away from the focusing mirror 105 and reach the image sensor 106. The light interacts with the pixels on the image sensor 106 to generate a voltage. The size of the image sensor 106 can affect the field of view. The resolution of the image sensor 106 can be determined by the pixel density, pixel size, and the focal length of the focusing mirror 105, which can be the distance between the focusing mirror 105 and the image sensor 106. The focal ratio (which is the focal length divided by the diameter of the focusing mirror 105), the pixel size of the sensor, and the quantum efficiency (which can be measured by the conversion between the number of electrons and the digital count in the image) can determine the sensitivity of the image sensor 106. A processor (not shown) can analyze the voltages generated from the groups of pixels to account for the spectral distribution in space.

[0033] Since the wavelengths will blur together in the diffraction grating 104, an offset of the resonance will occur. Blurring will occur if two wavelengths diffract and overlap with each other when being read by the pixels in the image sensor 106. The blurring is caused by the resolving power of the diffraction grating 104. If the gratings in the diffraction grating 104 are too thin or too closely spaced, or if the light enters at an angle, the wavelengths will overlap. When the wavelengths overlap, the ability to read the wavelengths is diminished. The offset of the resonance will result in a poor signal, and the angular tolerance can be below 2°. Figure 1 Spectrometers of can only provide a spectrum. Due to design and space constraints, they may not be able to image the target while providing the spectrum (which may require a separate set of optical devices and detectors specifically for that purpose).

[0034] Due to the size and cost of the components, Figure 1 the spectrometers in can be used by technical experts for highly specialized applications rather than for consumer devices. This can be beneficial for realizing a high-performance, ultra-compact spectrometer that can be integrated into a handheld device such as a smart phone. In addition to the performance parameters of the spectrometer such as high resolution, high throughput, and large spectral range, it can also be beneficial for the handheld spectrometer to have a large input angle tolerance. A high angular tolerance can increase the throughput of the device, and can allow them to tolerate a greater misalignment between the spectrometer and the spectral target, and may also have a larger field of view. This can be beneficial for handheld applications where an untrained user can hold the spectrometer in their hand and obtain good measurements without achieving the same precise alignment practiced in a fixed laboratory environment.

[0035] Figure 2Depicts a sensor (e.g., a spectrometer, a spectrometer and an imaging device, etc.) 200 according to some embodiments of the present disclosure. The sensor 200 may be an ultra-compact spectrometer sensor. The sensor 200 may also be an ultra-compact combined imaging and spectrometer sensor. Incident light 201 may enter the aperture 202, and the aperture 202 may be used to focus the light onto the dispersion array 204. In one embodiment, the aperture 202 may limit the field of view to + / - 15°; however, in some embodiments, the field of view may be larger or smaller. The aperture 202 may be a triplet lens that provides near-field spectroscopy, but it may also be other lens types. For example, the aperture 202 may also be a slit similar to the entrance slit 102 and may have a wider field of view (such as, + / - 30°). In one embodiment, the surface area of the dispersion array 204 may be approximately 1 square millimeter, but it may be smaller or larger. The dispersion array 204 may include nanophotonic components.

[0036] As used herein, "scattering" may be defined as the deviation of a light ray from its initial trajectory. "Dispersion" may be defined as light that can be separated into its component wavelengths. The dispersed light may also be scattered light.

[0037] The dispersion array 204 may scatter the incident light 201 within a first wavelength range and a second wavelength range, which will be described in more detail later. The dispersion array 204 may allow light within the first wavelength range to pass through with little or no dispersion, and may disperse light within the second wavelength range. The dispersion array 204 may be integrated with the aperture 202 to allow the aperture 202 to be fabricated in the same process as the dispersion array 204.

[0038] The incident light 201 passing through the aperture 202 and the dispersion array 204 can then pass through the lens 205. The lens 205 can focus the light onto the image sensor 206. In one embodiment, the lens 205 can be an optical lens, a meta-lens, or other lens. In an alternative embodiment, the aperture 202 can be integrated with the dispersion array 204 and the lens 205. In yet another alternative embodiment, the aperture 202, the dispersion array 204, the lens 205, and the image sensor 206 can all be integrated together. In one embodiment, the image sensor 206 can be used to read only spectral data. In another embodiment, the image sensor 206 can be used to read both image and spectral data. The image sensor 206 can have an internal region 208 and an external region 209. The image sensor 206 can simultaneously read spectral data in a second wavelength range within the external region 209 and image data in a first wavelength range within the internal region 208, which will be described in more detail below. Reading both image and spectral data can enable the sensor 200 to distinguish between "real" and "fake" objects. For example, if the object being analyzed is a physical object and a photograph of the object is presented to the sensor 200, the photograph of the object may appear to be the same image as the original object, but the spectral data of the photographed object may be different. The spectral data can be used to detect these differences between "real" and "fake" images.

[0039] The image sensor 206 can be a CMOS sensor or any of the sensors described previously, or can be any other sensor capable of detecting the wavelengths of the imaging and spectral sensor 200 designed for combination. The image sensor 206 can be connected to an image processor 207, which can process the image and / or spectral data. The image processor 207 can reconstruct the visualization data and / or spectral data.

[0040] The sensor 200 can be small enough to be used as a smartphone camera and can provide a hybrid function of imaging and spectroscopy. The size of the sensor 200 can be 0.1 to 3 cubic millimeters or less, allowing it to be assembled in a small form factor device. The dispersion array 204 can have a volume of approximately 0.01 cubic millimeters. For example, in some embodiments, to enable a smartphone camera to use the sensor 200, the dispersion array 204 can be placed on top of the layer of the camera lens or between the layers of the camera lens. The smartphone camera can include the lens 205, the aperture 202, the image sensor 206, and the image processor 207. Depending on the design, the dispersion array 204 can be placed before or after the smartphone lens or aperture. In another embodiment, the sensor 200 can be integrated into the smartphone camera.

[0041] Figure 3Depicts a dispersion array 204. The dispersion array 204 may include an array of dispersion structures 300a to 300n. The first dispersion structure 300a may allow light in a first wavelength range to pass through with reduced dispersion or no dispersion and reduced scattering or no scattering, and scatter and disperse light in a second wavelength range. In one embodiment, the dispersion structures 300a to 300n may each be approximately 500 micrometers by 500 micrometers square, but may be other sizes and shapes. The dispersion structures 300a to 300n may disperse light in different corresponding wavelength ranges. For example, for the dispersion structures 300a to 300n, the first dispersion structure 300a may disperse light in the wavelength range from 800 nm to 820 nm, while the second dispersion structure 300b may disperse light in the wavelength range from 820 nm to 840 nm, and so on.

[0042] Each of the dispersion structures 300a to 300n may disperse light in a different subset of the wavelength range or bandwidth that is dispersed for the entire dispersion array 204. For example, the dispersion wavelength range for the dispersion array 204 may be from 800 nm to 1000 nm, and if there are 8 dispersion structures 300a to 300n (n = 8), then each of the dispersion structures 300a to 300n may disperse a bandwidth of approximately 25 nm within the range of 800 nm to 1000 nm. In an alternative embodiment, for a given subset of the wavelength range, there may be multiple dispersion structures 300a to 300n to provide redundancy. For example, the dispersion array 204 may include 16 dispersion structures 300a to 300n, and the wavelength range is from 800 nm to 1000 nm, and the dispersion array 204 may be designed such that each individual dispersion structure 300a to 300n disperses a bandwidth of approximately 25 nm within the range of 800 nm to 1000 nm, but there are two of the dispersion structures 300a to 300n that share the dispersion bandwidth.

[0043] The dispersion structures 300a to 300n may disperse light along a single axis. For example, as will be further described and discussed below, the incident light 201 may be dispersed along an axis perpendicular to the rows of nanostructures 403a to 403n formed on the dispersion structures 300a to 300n. The dispersion structures 300a to 300n may be positioned to provide light scattering and dispersion at different angles relative to each other. In other words, each of the dispersion structures 300a to 300n disperses along one axis, and the axis of dispersion from one dispersion structure to another among the dispersion structures 300a to 300n is offset by a certain angle. This principle is in Figure 3, because each of the dispersion structures 300a to 300n has a row of nanostructures 403a to 403n formed at an angle relative to the other dispersion structures 300a to 300n. For example, the first dispersion structure 300a may have a corresponding first dispersion structure angle 301a, which may be an axis along which the first dispersion structure 300a disperses light. The nth dispersion structure 300n may have a corresponding nth dispersion structure angle 301n, and so on. Thus, each of the dispersion structures 300a to 300n may have a corresponding dispersion structure angle 301a to 301n.

[0044] In one embodiment, the angle at which light is dispersed between the dispersion structures 300a to 300n may be selected to provide a maximum difference in the dispersion structure angle 301a to 301n from one dispersion structure to another dispersion structure of the dispersion structures 300a to 300n. For example, for n dispersion structures 300a to 300n, the difference in the angle of the dispersion axis between the respective dispersion structures 300a to 300n may be n / 180°. For example, if n is 8 for the dispersion structures 300a to 300n, the dispersion structures 300a to 300n may each be rotated approximately 22.5° from 0° to 180°, providing a maximum angular difference from each other. In an alternative embodiment, two or more dispersion structures 300a to 300n may share a dispersion structure angle 301a to 301n for redundancy. In an alternative embodiment, the dispersion structures 300a to 300n may disperse light along two axes or in a conical shape.

[0045] Figure 4 Depicted is a diagram of a process according to some embodiments of the present invention. Figure 3 A cross-sectional view of an example dispersion array 204 is shown. Figure 4 In FIG. 1 , three dispersion structures are shown for example purposes: 300a, 300b, and 300n. The principles discussed can be applied to the first dispersion structure 300a and can be applied to the second dispersion structure 300a. Figure 3 2 and 3. The first dispersion structure 300a is a dispersion array 204 and dispersion structures 300a to 300n. Incident light 201 may enter the first dispersion structure 300a at an angle range 401. In some embodiments, the angle range 401 may be between 0° and + / -30°, but may be other ranges. The structure of the first dispersion structure 300a and the interaction of the incident light 201 with the first dispersion structure 300a are further described below.

[0046] The first dispersion structure 300a may include a multilayer system that includes a nanostructure layer 402 and a filter layer 404. The nanostructure layer 402 may scatter incident light 201 into scattered light 408, and the filter layer 404 may disperse the light into dispersed light 410. In one embodiment, each of the dispersion structures 300a to 300n may scatter and disperse the incident light 201 at dispersion structure angles 301a to 301n in a similar manner. The nanostructure layer 402 may be referred to as a scattering layer, which may be used to scatter the incident light 201. The filter layer 404 may be referred to as a dispersion layer, which may be used to disperse the light. The dispersed light 410 may include light of different wavelengths at different angles. For example, a first wavelength may be dispersed at 0° and may be referred to as the target wavelength 409, while a second wavelength may be dispersed at 10°. There may be dispersed light 410, and the dispersed light 410 may include a wavelength range and may be based on the optical properties of the filter layer 404. The near-field response 411 may be a response to the scattering and dispersion of the incident light 201 within the first dispersion structure 300a and for the first few wavelengths of the dispersed light 410 after the light exits the first dispersion structure 300a. The far-field response 415 may be a scattering and dispersion response of the incident light 201 after the near-field response 411. Both of these are discussed in more detail below.

[0047] The dispersed light 410 may include light of various wavelengths for different angles. More specifically, as will be described below, the dispersion angle at which the dispersed light 410 exits the first dispersion structure 300a depends on its wavelength. The nanostructure layer 402 may include nanostructure rows 403a to 403n (which extend along the Z-axis and are shown as 403a, 403b, ……, 403n-1 and 403n) of nanostructures (shown later) that may scatter light. The incident light 201 may enter the nanostructure layer 402, and the light may interact with the nanostructure rows 403a to 403n. Some of the incident light 201 may be scattered around the nanostructure rows 403a to 403n and may generate a wavefront. The wavefront may be a scattering of the electric field and may define the propagation of the light field. The wavefront may have units of volts-meter and may be considered a force. The wavefront may follow the Huygens-Fresnel principle, where each point on the wavefront may act as a source of spherical secondary microwaves. The sum of the secondary microwaves may determine the form of the subsequent waves that may generate the far-field response 415. The wavefront may have waves with varying phases and amplitudes, and these waves may add together to generate the far-field response 415. As described below, after the incident light 201 interacts with and is scattered by the nanostructure layer 402, the resulting light may interact with the filter layer 404.

[0048] The filter layer 404 may include alternating materials of a first layer 405 and a second layer 406, which will be for Figure 5Further discussion. The defect layer 407 can disperse light in a wavelength range. For each of the dispersion structures 300a to 300n, from one dispersion structure among the dispersion structures 300a to 300n to another dispersion structure, the defect layer 407 can vary in thickness across the dispersion array 204 (see, for example Figure 4 , where the defect layer 407 has different thicknesses between the dispersion structures 300a, 300b, and 300n, respectively). The varying thickness of the defect layer 407 for each of the dispersion structures 300a to 300n can cause light in different wavelength ranges to be filtered and dispersed at different angles. In some embodiments, for each of the dispersion structures 300a to 300n, the defect layer 407 can have a different thickness. In other embodiments, for two or more of the dispersion structures 300a to 300n, the defect layer 407 can have the same thickness to provide redundancy.

[0049] The scattered light 408 can include a first set of wavelengths and a second set of wavelengths. The scattered light 408 of the first set of wavelengths can pass through the filter layer 404 with little or no dispersion within the first angular range 412 and can be referred to as specular light. The scattered light 408 of the second set of wavelengths can be scattered and dispersed into colored light 410 within the second angular range 413. The second angular range 413 can fall on the image sensor 206, or a subset of the second angular range 413 can fall on the image sensor 206.

[0050] In one embodiment, the second angular range 413 can be used to read spectral data. For example, from 0 degrees to the end of the image sensor 206, the wavelengths that are scattered and dispersed within the second angular range 413 and reach the image sensor 206 can be spectrally read.

[0051] In another embodiment, as will be described later, the spectral reading angular range 414 can be a non-overlapping angular range between the second angular range 413 and the first angular range 412. The spectral reading angular range 414 can fall on the image sensor 206, or can extend beyond the image sensor 206. The spectral reading angular range 414 can be the angular range within which the colored light 410 can be spectrally read by the image sensor 206 and can be referred to as non-specular light.

[0052] As a specific example, in one embodiment, the incident light 201 may enter the nanostructure layer 402 between 0° and + / -30°. In the range of the input angle of 0° to + / -30° for the incident light 201, for the visible spectrum, the output dispersion may be from 0° to + / -15°, and for the NIR spectrum, the output dispersion may be from 0° to + / -30°; however, in other embodiments, other angles and wavelengths (from radio wavelengths to gamma wavelengths) are possible. In a spectral-only reading configuration, the image sensor 206 may be used to read spectral data from 0° to + / -30°. In an imaging and spectral reading configuration, the image sensor 206 may use 0° to + / -15° to read image data and use + / -15° to + / -30° to read spectral data.

[0053] In one embodiment, the nanostructure layer 402 may allow the first dispersion structure 300a to provide an angular tolerance of + / -30°, which means that any incident light 201 entering between 0° and + / -30° will provide the same output scattering and dispersion angles. The output dispersion angle and the angular tolerance may be due to the structure of the nanostructure layer 402. A more detailed description of the interaction of the incident light 201 with each layer is provided below. In addition, the materials and structures are also described in more detail.

[0054] The nanostructure layer 402 may be referred to as an optical metasurface. The metasurface may include one or more planar surfaces of a phase-shift array of spatially arranged nanoantennas or an array of nanopores (which may be referred to as scatterers) to scatter light.

[0055] In some embodiments, the nanostructure layer 402 may include a dielectric-based metasurface material. The nanostructure layer 402 may include a dielectric or semiconductor having a high refractive index. The high refractive index may scatter light more effectively. Additionally, a material with low light absorption may allow more light to be transmitted. Example materials used include, but are not limited to, titanium dioxide, silicon nitride, silicon, germanium, hafnium oxide, aluminum oxide, or tellurium. These dielectric materials may be capable of resonantly trapping light and re-emitting light with different phases, polarizations, modes, and spectra.

[0056] The nanostructure layer 402 may be capable of bending light through a phase change at its interface and may be described by a generalized version of Snell's law. When light passes between two media, namely air and the nanostructure layer 402, it may refract at the interface. In some embodiments, by changing the metasurface structure of the nanostructure layer 402 as described herein, the phase change of light may vary from 0 to 2-pi. The value of the phase change may be controlled by the size and orientation of the features of the metasurface. When magnetic resonance and electric resonance overlap, the phase change may cover the entire 2-pi range.

[0057] More specifically, in some embodiments, the first dispersion structure 300a may have incident light 201 entering through the nanostructure layer 402. The incident light 201 may be manipulated by the nanostructure layer 402 through Mie scattering to provide wavelength-dependent scattering. The resulting scattered light 408 may have a changed phase and amplitude. Next, a more detailed description of the filter layer 404 is provided.

[0058] The filter layer 404 may be a reflector. The filter layer 404 may be located on one side of the nanostructure layer 402. The filter layer 404 may reflect some wavelengths while selectively allowing other wavelengths in a narrower wavelength range to pass through. The filter layer 404 may disperse the target wavelength range of the scattered light 408 into dispersed light 410. The dispersed light 410 may include wavelengths dispersed at different angles (depending on the wavelength) and may include the target wavelength 409. The target wavelength 409 may be the wavelength dispersed at 0° by a particular filter layer 404. The target wavelength range may be based on the target wavelength 409 and may include the range of wavelengths of the scattered light 408 dispersed by the filter layer 404. The output angle range resulting from the dispersion of the target wavelength range may be the second angle range 413.

[0059] The filter layer 404 may disperse the wavelengths of the scattered light 408 at an angle in a wavelength-dependent manner to form the dispersed light 410. For example, for an exemplary embodiment of the first dispersion structure 300a, the target wavelength 409 may be 835 nm, and the target wavelength range of the dispersed light 410 may be 800 nm to 835 nm. The target wavelength 409 of 835 nm may be dispersed at 0°. The wavelength of 820 nm may be dispersed at + / -15°, and the wavelength of 800 nm may be dispersed at + / -30°. The filter layer 404 may include a defect layer 407 that may determine the target wavelength range of the dispersed light 410 and which specific wavelengths may be dispersed at which specific fixed angles. The thickness of the defect layer 407 may vary for each of the dispersion structures 300a to 300n to allow the dispersion array 204 to disperse a wide range of wavelengths, as will be discussed further below.

[0060] The filter layer 404 may be a distributed Bragg reflector (DBR), a dielectric mirror, a fiber Bragg grating, a semiconductor Bragg mirror, or other types of devices. The filter layer 404 may be a type of reflector formed by multiple layers of alternating materials with varying refractive indices. In one embodiment, the filter layer 404 may be a DBR filter having multiple layers.

[0061] In one embodiment, the filter layer 404 may include one or more alternating layers of a first layer 405 and a second layer 406, but there may be more types of layers, and the same principles below may apply. The first layer 405 and the second layer 406 may be alternated on top of each other multiple times and may have a constant thickness or may vary in thickness. The defect layer 407 may be a constant thickness layer of a material including the material of the first layer 405 or the second layer 406 (in this example, the defect layer 407 is shown to have the same material as the material of the first layer 405) or may be a layer with a varying thickness. In some embodiments, the defect layer 407 may be an alternating material.

[0062] The first layer 405 and the second layer 406 may have boundaries that can cause partial reflection of light waves and may provide interference to the incident light 201, which can block certain wavelengths. The first layer 405 and the second layer 406 may have different refractive indices that can allow certain wavelengths to pass through and change phase, which can result in wavelength-dependent angular dispersion. The refractive index of a material can vary according to the wavelength of the light entering the material, and thus, the refractive index values provided can be an average of a range of wavelengths. In one embodiment, the first layer 405 may be TiO2. The refractive index of TiO2 may be about 2.45 and may be considered a high refractive index. In one embodiment, the second layer 406 may be SiO2. The refractive index of SiO2 may be about 1.45 and may be considered a low refractive index. The two refractive index values may be higher or lower. These two values may depend on the specific wavelength of the light passing through, and it may be helpful to consider the refractive index as an average over the wavelength range of interest. The same principles above may apply to additional layers (including the defect layer 407 and layers of other materials).

[0063] The first layer 405 and the second layer 406 may have different thicknesses, which can also determine which wavelengths can pass through the material. The reflectivity of the first layer 405 and the second layer 406 together may depend on the configuration of the regions of destructive interference of the light reflected at the boundaries of each layer.

[0064] For each layer of material, light can have a phase delay within the material of the first refractive index n. Light can follow the rule c = λf, where c is the speed of light, λ is the wavelength, and f is the frequency. When light passes through the material of the first refractive index n, the speed of light can be changed by multiplying by 1 / n. Since the frequency f can be fixed, the wavelength λ can also be changed by multiplying by 1 / n (referred to as the effective wavelength). The effective wavelength of light can change within the material. In addition, the thickness d of the material can allow light of the first wavelength to pass through, while light of other wavelengths can be reflected. Light of other wavelengths can be reflected from the outer surface and the inner surface. The light reflected from the inner surface of the material can have a phase delay, and the phase delay can interact with the light reflected from the outer surface to produce interference, which can be constructive or destructive. Therefore, the refractive index together with the thickness of the material can allow the selected wavelength to pass through the material. When the first layer 405 is stacked on top of the second layer 406 in the Y direction, using the principles described herein, the reflections of the two layers can filter out many wavelengths while allowing a narrow wavelength range to pass through. The first layer 405 and the second layer 406 together can be referred to as a stack. These layers are described in more detail below. The following principles can also be applied to additional layers in the stack (such as the defect layer 407 or more layers).

[0065] In some embodiments, the first layer 405 and the second layer 406 can each be a single corresponding material and can each be a dielectric material. The first layer 405 can have a high refractive index, while the second layer 406 can have a low refractive index, or both can have a high refractive index. The first layer 405 and the second layer 406 can be repeatedly stacked on top of each other, which can produce Fresnel reflections at the interfaces of the alternating layers. The first layer 405 can have a refractive index n1, and the second layer 406 can have a refractive index n2. Together, the Fresnel reflection can be [(n1 - n2) / (n1 + n2)] 2 。

[0066] The effective thickness of a material can be its refractive index multiplied by the thickness of the material and can be used to determine the dispersion characteristics of the material. This concept can be applied to the first layer 405 and the second layer 406. When the first layer 405 and the second layer 406 are combined into a stack, the effective thickness can be used to tune the filter layer 404 to disperse a target wavelength range. Adding subsequent stacks on top of each other will allow for greater dispersion efficiency, but since the effective thickness of each stack can be the same, the target wavelength range will not change. When the defect layer 407 is added to the stack, the target wavelength range can be tuned as the effective thickness changes. As will be discussed later, the dispersion array 204 can have the same stack for each of the dispersion structures 300a to 300n, but can have a defect layer 407 with varying thicknesses, which can allow for different target wavelength ranges for each of the dispersion structures 300a to 300n.

[0067] When combined to form a stack, the effective thickness of the first layer 405 and the second layer 406 can be the thickness multiplied by the refractive index, and the effective thickness can be approximately half or a quarter of the target wavelength 409, where the target wavelength 409 can have zero dispersion. For example, for the thickness d1 of the first layer 405 and the thickness d2 of the second layer 406 respectively, the effective thickness can be n1×d1 + n2×d2 and can be tuned to be approximately equal to half or a quarter of the target wavelength 409. Additional stacks of the same thickness can be added to increase the dispersion efficiency, but the same target wavelength 409 can have zero dispersion. In other cases, if a defect layer 407 with a refractive index n1 and a thickness d3 is included, the formula can be n1×d1 + n2×d2 + n1×d3 and can be approximately equal to half or a quarter of the target wavelength 409. The stack and the defect layer 407 can be used to determine the target wavelength range. As previously mentioned, the target wavelength range of the filter layer 404 can be the wavelength range in which dispersion can occur in each of the dispersion structures 300a to 300n and is based on the target wavelength 409 for a particular dispersion structure.

[0068] In an alternative embodiment, using the principles described above, each of the dispersion structures 300a to 300n can target a wavelength range using different materials and / or thicknesses of the stack of the first layer 405 and the second layer 406. The stack can contain more than two layers, and each layer can have different materials and thicknesses. In an embodiment with multiple stacks, each stack can also include different materials and thicknesses, or they can be the same materials and thicknesses.

[0069] An effective thickness equal to one-half of the target wavelength of 409 can result in constructive interference and can be used as a high-reflection material. An effective thickness equal to one-quarter of the target wavelength of 409 can result in destructive interference and can be used as a low-reflection material. By stacking multiple alternating first layers 405 and second layers 406 on top of each other, a more effective phase shift can occur, which can allow for a more effective filter. In one example, by stacking four layers of the first layer 405 and the second layer 406, the resolution of wavelength dispersion can be between 2 nm and 5 nm. If more stacks are added, the resolution will decrease (higher values (such as, 5 nm to 10 nm)). If fewer stacks are added, then the resolution can increase (lower values (such as, 1 nm to 2 nm)).

[0070] In one embodiment, by stacking the first layer 405 and the second layer 406, the period of the light wave of the incident light 201 can be shifted by pi, which results in destructive interference, thereby blocking or filtering the selected wavelength while allowing other wavelengths to pass through the filter. Each layer in the filter layer 404 can have a boundary that can cause partial reflection of the light wave. When multiple layers are added together to form a stack, many reflections can combine with constructive (half-wavelength) interference or destructive (quarter-wavelength) interference and can reflect the selected wavelength or block the selected wavelength from passing through the filter layer 404.

[0071] For a simple example of destructive interference in the absence of the defect layer 407, if the target wavelength 409 is 800 nm, the first layer 405 and the second layer 406 can have an effective thickness that is a combination of two quarter-wavelength filters, and each of the two quarter-wavelength filters can shift the wavelength by 200 nm or a total of 400 nm. By shifting the 800 nm wavelength by 200 nm twice (i.e., a total shift of 400 nm), there will be destructive interference and the target wavelength 409 will be blocked. However, in constructive interference, the target wavelength 409 can be allowed to pass through.

[0072] In another embodiment, the effective thickness of the stack including the first layer 405 and the second layer 406 can be smaller than half or a quarter of the thickness of the target wavelength 409, but when multiple stacks are added together, their sum can be half or a quarter of the thickness of the target wavelength 409. In other embodiments, more variables (including their refractive indices, thicknesses, and more as described herein) can be used to determine the effective thickness of the first layer 405 and the second layer 406.

[0073] As will be discussed below, the defect layer 407 can also change the target wavelength 409 that can be filtered, and by changing the effective thickness of the defect layer 407, the dispersion structures 300a to 300n can be tuned to allow various target wavelengths 409 of the scattered light 408 to be dispersed as part of the light 410 with an approximate angle of 0°.

[0074] The defect layer 407 can modify the range of target wavelengths to be dispersed. For each of the dispersion structures 300a to 300n, the defect layer 407 can include steps having different thicknesses, which are shown as thicknesses varying along the Figure 4 X-axis. The first step thickness can allow the first target wavelength range to be dispersed in the first dispersion structure 300a, and the nth step thickness can allow the nth target wavelength range to be dispersed in the nth dispersion structure 300n. For example, for each step thickness in the defect layer 407 in the dispersion structures 300a to 300n, the target wavelength ranges can be within 20 nanometers to 40 nanometers of each other, but other wavelength ranges can be available and can be selected depending on the material (e.g., refractive index) and step size of the defect layer 407.

[0075] Over the entire range of the dispersion structures 300a to 300n on the dispersion array 204, the thicknesses of the defect layer 407, the first layer 405, and the second layer 406 together can select the entire range of wavelengths that can be dispersed. For example, for the first dispersion structure 300a, the target wavelength range can be 700 nm to 725 nm, for the second dispersion structure 300b, the target wavelength range can be 725 nm to 750 nm, and so on, for the nth dispersion structure 300n, the target wavelength range can be 875 nm to 900 nm. For the dispersion array 204, the entire range of wavelengths that can be dispersed can be 700 nanometers to 900 nanometers. Each of the dispersion structures 300a to 300n can disperse more wavelengths than the wavelengths in their respective target wavelength ranges, but these wavelengths can be at a dispersion angle wider than the dispersion angle at which the waves will not fall on the image sensor 206. Thus, the defect layer 407 can be designed to place a specific portion of the dispersion spectrum (target wavelength range) within a specific angle range (which can be the second angle range 413 or the spectral reading angle range 414) onto the image sensor 206 as defined by the physical size and arrangement of the image sensor 206.

[0076] More specifically, and also referring to Figure 3, each of the dispersion structures 300a to 300n may have a defect layer 407 with a different thickness from the other dispersion structures 300a to 300n to allow for dispersion of a wide range of wavelengths across the dispersion array 204. More specifically, if the thickness of the step of the defect layer 407 as described above is x and the base height of the layer required for the target wavelength 409 is n (as described previously), then the first dispersion structure 300a may have a thickness of approximately n + x, the second dispersion structure 300b may have a thickness of n + 2x, and the third dispersion structure 300c may have a thickness of n + 3x, and so on.

[0077] More specifically, in some embodiments, the defect layer 407 may have various thicknesses (one thickness per dispersion structure 300a to 300n) to allow light in a varying target wavelength range to pass through. For each of the dispersion structures 300a to 300n, there may be a target wavelength 409 (which may be defined as the wavelength at which light is dispersed at 0°). The target wavelength 409 for each of the dispersion structures 300a to 300n may be different or may be shared by two or more of the dispersion structures 300a to 300n to provide redundancy.

[0078] As previously described, the dispersion structures 300a to 300n may not "stop" dispersing wavelengths at the ends of their respective wavelength ranges (e.g., 700 nm to 725 nm). Instead, the dispersed wavelengths that exceed the physical boundaries of the image sensor 206 (e.g., beyond + / - 30° in some embodiments) are not sensed and are not considered part of the "wavelength range" of this discussion. That is, the dispersion wavelength range for each of the dispersion structures 300a to 300n starts at 0° for the target wavelength 409 and extends to the angle defined by the outer limits of the image sensor 206.

[0079] For example, for Figure 3For the dispersion array 204, there may be n = 8 dispersion structures 300a to 300n. Additionally, for example, the dispersion array 204 may be capable of dispersing wavelengths from 700 nm to 900 nm. According to this example, the dispersion structures among the dispersion structures 300a to 300n may each disperse a target wavelength range of approximately 25 nm. The first dispersion structure 300a may disperse light from 700 nm to 725 nm (which may be the first target wavelength range). The target wavelength 409 with approximately 0° dispersion may be 725 nm. The 700 nm wavelength may be dispersed at + / - 30°, and the wavelengths between 700 nm and 725 nm may be dispersed at a lower angle. The defect layer 407 may be of a first thickness for the first dispersion structure 300a. The second dispersion structure 300b may disperse light from 725 nm to 750 nm (which may be the second target wavelength range). The target wavelength 409 with approximately 0° dispersion may be 750 nm. For the second dispersion structure 300b, the defect layer 407 may have an increased thickness (relative to the first dispersion structure 300a) to disperse different target wavelengths 409 at 0° and have a second target wavelength range (relative to the first dispersion structure 300a). For example, when the refractive index of the defect layer 407 is 1.25, the increased thickness may be 20 nm, thus allowing a 1.25×20 = 25 nanometer shift in the target wavelength 409 to be dispersed and the wavelength range. Of course, if a different target wavelength 409 shift or material refractive index is desired, a different defect layer 407 thickness may be used.

[0080] In some embodiments, from the dispersion structures 300a to 300n, the defect layer 407 may have an incrementally increasing thickness in the above manner to allow for the dispersion of the entire target wavelength range.

[0081] In some embodiments, the image sensor 206 may read imaging data from a first angular range 412 and spectral data from the color-dispersed light 410 in a spectral read angular range 414. In an exemplary embodiment, the spectral read angular range 414 may be from + / - 15° to + / - 30°, and the first angular range 412 for reading imaging data may be from 0 degrees to + / - 15 degrees. To compensate for the fact that some angles of the color-dispersed light 410 may not be used for spectral data, an overlap portion in the target wavelengths 409 among the dispersion structures 300a to 300n designed according to the principles disclosed herein may be used.

[0082] For example, the first dispersion structure 300a may have a first target wavelength range that disperses light in the range of 700 nm to 735 nm. The target wavelength 409 with approximately 0° dispersion may be 735 nm. The 700 nm wavelength may be dispersed at + / - 30°, and the 725 nm wavelength may be dispersed at + / - 15°. Thus, for example, the first dispersion structure 300a may provide spectral reading in the range of ~700 nm to 725 nm, and light with wavelengths from 725 nm to 735 nm falls outside the spectral reading angle range 414 on the image sensor 206 (but within the first angle range (imaging data angle) 412).

[0083] The second dispersion structure 300b may have a thicker defect layer 407. The second dispersion structure 300b may have a second target wavelength range that disperses light in the range of 725 nm to 760 nm. The target wavelength 409 with approximately 0° dispersion may be 760 nm. The 725 nm wavelength may be dispersed at + / - 30°, and the 750 nm wavelength may be dispersed at + / - 15°. Thus, the second dispersion structure 300b may provide spectral reading in the range of 725 nm to 750 nm, and light from ~750 nm to 760 nm falls outside the spectral reading angle range 414 of the image sensor 206. Thus, the target wavelength range of the second dispersion structure 300b may compensate for the fact that some of the target wavelength range of the first dispersion structure 300a is not measured. Then this principle of overlap can be repeated on the dispersion structures 300a to 300n to allow continuous coverage of wavelengths from 700 nm to 900 nm.

[0084] Details of the target wavelength ranges (and associated target wavelengths 409) that may be sought for the respective dispersion structures 300a to 300n may be based on the angle at which the image sensor 206 can gather image data and spectral data (which may be based on the physical design parameters of the image sensor 206), the number of dispersion structures 300a to 300n and any redundancy sought, the entire wavelength range of the spectrum to be analyzed by the sensor 200, and various other factors that will be apparent to those skilled in the art after reading this disclosure. Figure 2 and the angle at which the image sensor 206 can gather image data and spectral data (which may be based on the physical design parameters of the image sensor 206), the number of dispersion structures 300a to 300n and any redundancy sought, the entire wavelength range of the spectrum to be analyzed by the sensor 200, and various other factors that will be apparent to those skilled in the art after reading this disclosure.

[0085] Return reference Figure 4 as will be in Figure 10As shown in more detail below, the intensity of the wavelength of the chromatic dispersion light 410 can vary with the angle of dispersion and can be referred to as the transmission angle intensity. The transmission angle intensity of the wavelength can be a function of the refractive index and thickness of the material of the filter layer 404, the composition of the nanostructure layer 402, the scattered light 408, and the number of stacks (the first layer 405 and the second layer 406) of the filter layer. The transmission angle intensity of each wavelength can be calculated, and a distribution of the angle intensity can be created. The dispersion of the chromatic dispersion light 410 can be calculated from the distribution. This calculation can be used to design the filter layer 404, including the thickness, material, and number of stacks of the first layer 405 and the second layer 406. More details are provided further below.

[0086] Figure 5 FIG. illustrates a process 500 for manufacturing a dispersion array 204 according to some embodiments. As Figure 4 discussed, the first dispersion structure 300a can include a nanostructure layer 402 and a filter layer 404. Figure 5 Cross-sectional views of the dispersion structures 300a to 300n can be shown, where additional layers of the nanostructure layer 402 or the filter layer 404 can be generated or used during the manufacturing process. In this example view, the defect layer 407 can have 8 steps, and a dispersion array 204 with 8 dispersion structures 300a to 300n side by side can be shown. The manufacturing of the dispersion array 204 can be monolithic; that is, the designs of all the dispersion structures 300a to 300n can be completed together.

[0087] The layer of the substrate 501 can be used as a substrate on which additional layers are added to the dispersion structures 300a to 300n. The substrate 501 can be glass, silicon, or other optically transparent materials in the wavelength range of interest. The substrate 501 can be used in the manufacturing process and can be disposed of after manufacturing. As shown in structure 510, the first layer 405 and the second layer 406 can be alternately deposited on each other to form a first filter layer 502. In one embodiment, the first layer 405 and the second layer 406 are two different materials; however, there can be additional layers using other materials. The first layer 405 can have a first thickness d1, and the second layer 406 can have a second thickness d2. The alternating first layer 405 and second layer 406 can have the same thickness d1 and d2, or their thicknesses can vary. The first filter layer 502 can allow filtering of selected wavelengths to pass through.

[0088] The defect layer 407 can be fabricated on top of the first filter layer 502. The defect layer 407 can include a stepped step pattern of different thicknesses. The varying thickness of the defect layer 407 can allow for the dispersion of different wavelength ranges of light. The defect layer 407 can be made from a defect preparation layer 504 and one or more defect lithography layers 503. The defect lithography layer 503 can be one or more photolithography masks and can be a polymer film. The defect preparation layer 504 can be the same material as one of the first layer 405 and the second layer 406, or it can be a different material. The defect preparation layer 504 can be deposited on top of the first filter layer 502. The defect lithography layer 503 can be deposited on top of the defect preparation layer 504, which can form a lithography structure 511. A photolithography mask and etching (in one or more repeating processes described in more detail below) can be applied to the defect lithography layer 503, which can change the structure of the defect preparation layer 504 and can form a structure 512 in its final form including the defect layer 407, which is described in more detail below.

[0089] Additional first layer 405 and second layer 406 can be deposited on top of the defect layer 407 alternately with each other to form a second filter layer 505. The first filter layer 502, the defect layer 407, and the second filter layer 505 can constitute Figure 4 the filter layer 404. Referring back Figure 5 , a cap stack 506 can be deposited and planarized on the second filter layer 505 to form a structure 513. The cap stack 506 can have a photolithography mask 507 temporarily deposited thereon to allow for the photolithographic generation of nanostructure rows 403a to 403n by etching to form a structure 514. When etching the nanostructure rows 403a to 403n for each of the dispersion structures 300a to 300n, the photolithography mask 507 can be removed to form a structure 515 that can be the dispersion structures 300a to 300n.

[0090] In one embodiment, the first layer 405 can be titanium dioxide (TiO2) and can be deposited by a sputtering method, but any other technique for depositing materials on the substrate 501 can be used.

[0091] The second layer 406 can be silicon dioxide (SiO2). The second layer 406 can be deposited by plasma-enhanced chemical vapor deposition (PECVD), but any other technique can be used for deposition.

[0092] In one embodiment, the first layer 405 can be 83 nm thick and the second layer 406 can be 135 nm thick to target a wavelength of 800 nm, and the first layer 405 includes TiO2 and the second layer 406 includes SiO2. Four stacks of the first layer 405 and the second layer 406 (alternating four layers of the first layer 405 and four layers of the second layer 406) stacked on top of each other can be present before the defect layer 407 for a total of eight layers. Fewer or more stacks can be present. Another four stacks of the first layer 405 and the second layer 406 can be present after the defect layer 407. To target other wavelengths, other thicknesses can be used as discussed herein. Fewer or more stacks can be present.

[0093] As previously described, the defect layer 407 can be formed by depositing a thicker layer of the first layer 405 or the second layer 406, which can be the defect preparation layer 504. A gray-scale lithography technique can be applied to form the defect layer 407. Ultraviolet (UV) exposure can be applied to the defect lithography layer 503. The defect lithography layer 503 can cover the entire surface of the defect preparation layer 504. In Figure 5 the example shown, UV irradiation can be applied in the X direction over the range 508, and the total dose of the UV exposure can vary over the range 508. UV irradiation can also be applied in the Z direction. A variable dose power or variable time dose of UV exposure can be applied, which will affect the durability of the defect lithography layer 503 under an etching process along the X direction, which can then result in a defect layer 407 of variable thickness. For example, the variable dose power levels for eight zones can have power levels of x, 7 / 8x, 6 / 8x,..., down to 1 / 8x power level. The variable time dose of the UV exposure can have the same power level x and can have times of t, 7 / 8t, 6 / 8t,..., down to 1 / 8t for each zone. After applying the UV exposure, an etching can be performed, which can produce the defect layer 407. The etching can be dry etching or wet etching.

[0094] In an example alternative method, a stepped structure of the defect layer 407 is produced from the defect preparation layer 504 using repeated etchant mask lithography. Specifically, in each round of lithography, an etchant mask covering one less step than the previous etchant mask stage is used, and the device is etched downward in height by one "step". By repeating this process, a stepped structure is produced.

[0095] Figure 6 A top-down view of an example dispersion structure 300a is depicted, and specifically shows Figure 4Top-down view of the nanostructured layer 402. Along the X-axis, nanostructured rows 403a to 403n are distributed. The nanostructured rows 403a to 403n may include a plurality of nanopores or nanoantennas (shown here as nanopores) extending along the Z-axis. The nanostructured rows 403a to 403n may be placed adjacent to each other along the X-axis and extend parallel to each other along the Z-axis. The nanostructured rows 403a to 403n may be distributed in a pattern, and the pattern may be a semi-random pattern. The distance between two adjacent nanostructured rows 403a to 403n may be randomly distributed along the X-axis between the minimum allowable distance and the maximum allowable distance of each adjacent row. In one embodiment, the nanostructured rows 403a to 403n may have a maximum distance that is half the length of the longest wavelength of the target wavelength range of the first dispersion structure 300a between adjacent rows (this may be the target wavelength 409). The semi-random pattern may be implemented using inverse transform sampling for uniform distribution. The semi-random pattern may allow low spatial correlation or no spatial correlation between adjacent nanostructured rows 403a to 403n. In the case of low spatial correlation or no spatial correlation, an angular range (range of incident angles) 401 may be allowed to allow a constant output scattering range of light over the first angular range 412 and the second angular range 413. Because there is no row pattern, the random distribution of the nanostructured rows 403a to 403n along the X-axis may allow the nanostructured layer 402 to operate independent of Figure 4 the polarization of the incident light 201, and thus the light is independent of the pattern.

[0096] In one embodiment, a nanostructured row (such as 403a) may include nanopores 601a to 601n. The nanostructured rows 403a to 403n may each include replicas of a group of nanopores 601a to 601n. The nanopores 601a to 601n may be similar or different in terms of radius, thickness, and the distance between adjacent nanopores within the subject nanostructured row (such as 403a). In one embodiment, the nanopores 601a to 601n may have a radius of 140 nm and a depth of 750 nm, but they may be larger or smaller.

[0097] In one embodiment, the nanopores 601a to 601n may be spaced from each other by approximately equal distances. The nanopores 601a to 601n may be placed closely together to allow light to pass through with little or no scattering in the Z direction. To allow light to pass through with little or no scattering in the Z direction, the condition to be satisfied may be:

[0098] λ≥n·d.

[0099] Wherein, the wavelength λ can be the wavelength of interest, n can be the refractive index of the nanopores 601a to 601n, and d can be the distance between adjacent nanopores 601a and 601b. For example, the nanopores 601a to 601n can have a distance of 10 nm to 200 nm between adjacent nanopores in the first row of nanostructures 403a, and can have a refractive index of about 1.5, which can allow the scattering of both visible light and NIR light. As described below, the non-scattering condition or low-scattering condition can be used for the design of one-dimensional structures.

[0100] The one-dimensional structure can provide a pattern in one dimension (such as, the distribution of the rows of nanostructures 403a to 403n along the X-axis). The pattern can be a repetitive distribution or a random distribution of the rows of nanostructures 403a to 403n, and will be discussed in more detail later. The one-dimensional structure can maintain consistency in the second dimension (such as maintaining the same number or position of nanopores 601a to 601n in the Z direction between the rows of nanostructures 403a to 403n); for each of the rows of nanostructures 403a to 403n, the same number or arrangement of nanopores 601a to 601n can be repeated.

[0101] The two-dimensional structure can provide a pattern in both the first and second dimensions. For example, the rows of nanostructures 403a to 403n can have a pattern along the X-axis direction. As mentioned before, the pattern can be the rows of nanostructures 403a to 403n randomly distributed between the minimum distance and the maximum distance along the X-axis. Additionally, the first row of nanostructures 403a can have a pattern of nanopores 601a to 601n in the Z direction within the row. For example, the first row of nanostructures 403a can have nanopores 601a to 601n with a pattern of different diameters, shapes, thicknesses, and spacings between each of the nanopores 601a to 601n.

[0102] As mentioned before, light can be scattered in one direction by the first dispersion structure 300a, and the one direction can be along Figure 6 the X-axis in (perpendicular to the rows of nanostructures 403a to 403n), but can be substantially non-scattering along the direction parallel to the rows of nanostructures 403a to 403n (shown as the Z-axis direction). This uniaxial scattering can be due to the compactness of the nanopores 601a to 601n in the Z direction. When the distance between two adjacent nanopores among the nanopores 601a to 601n is smaller than the wavelength of the incident light 201, it allows the light to substantially pass through with little or no scattering. Then, since the rows of nanostructures 403a to 403n are spaced far enough apart (according to a semi-random distribution), scattering can occur along the X-axis to prevent certain wavelengths of light from passing through without scattering.

[0103] More specifically, the radius r of the first nanopore 601a can impart a phase shift θ in the incident light 201, which can result in the near-field response 411 as shown and previously described in Figure 4 . The near-field response 411 of a single nanopore, such as the first nanopore 601a, can be referred to as Figure 4 . The near-field response 411 can include the sum of the near-field responses 411 of the nanopores 601a to 601n for all the nanopore rows 403a to 403n of Figure 6 .

[0104] The radius r of the first nanopore 601a can allow for more scattering (if larger) and less scattering (if smaller), and can be due to Mie scattering. The light scattered by a single first nanopore 601a can be scattered in a conical shape. In one embodiment, the radius r can be about 140 nm to 150 nm; however, the radius can be larger or smaller depending on the target wavelength 409. As will be discussed below, when the nanopores 601a to 601n form the first nanopore row 403a, the closeness of the nanopores 601a to 601n to each other in the Z direction can allow light to pass through and be substantially non-dispersive in the Z direction.

[0105] When the nanopore rows 403a to 403n are distributed in the X direction, Figure 4 the scattering of the incident light 201 can be substantially limited to the X direction. The nanopore rows 403a to 403n can be designed to scatter light of a selected wavelength and at a selected angle due to Mie scattering by selecting the radius r of the nanopores 601a to 601n and semi-randomly distributing the nanopore rows 403a to 403n. The average distance between all the nanopore rows 403a to 403n can determine whether light scatters and at what wavelength.

[0106] In one embodiment, the distribution of the rows can depend on the density of the nanopore rows 403a to 403n. The density of the nanopore rows 403a to 403n can be the surface area of the nanopores 601a to 601n divided by the total surface area. For a one-dimensional configuration, the density can be higher when the nanopore rows 403a to 403n are closer to each other, and the density can be lower when the nanopore rows 403a to 403n are farther apart. The spacing between the nanopore rows 403a to 403n can be referred to as the row density. The row density can be the count of the nanopore rows 403a to 403n per unit length on the first dispersion structure 300a and can be used to determine the density of the one-dimensional configuration. By changing the row density, the efficiency of the first dispersion structure 300a can be changed.

[0107] If the sensor 200 reads both image data and spectral data, the efficiency can be the ratio of the intensity of the dispersed light 410 in the second angular range 413 to the intensity of the incident light 201. If the sensor 200 reads only spectral data, the efficiency can be the intensity of the dispersed light 410 in the spectral read angular range 414 divided by the intensity of the incident light 201. The intensity can be measured in lux. The efficiency can also be referred to as the relationship between the intensity of the non-mirror forward-scattered light that is dispersed and spectrally read by the image sensor 206 and the intensity of the incident light 201. The efficiency can be used to determine the density of the nanostructure rows 403a to 403n. Mirror (as opposed to non-mirror) forward-scattered light can include zero-order transmitted light (which can be the scattered light 408). Non-mirror forward-scattered light can include higher-order or non-zero-order transmitted light (which can be light dispersed at non-zero angles). The image sensor 206 can read the spectrum of the non-mirror light. Higher efficiency can lead to a higher probability of scattering the incident light 201. As will be described in more detail below, the scattering of the incident light 201 can be determined based on the target wavelength 409, the pore density, and the row density.

[0108] As described below, to determine the efficiency of the first dispersion structure 300a for the nanostructure rows 403a to 403n of a given density, the near-field response of the nanopores 601a to 601n analyzed below can be performed. The near-field response 411 can depend on the radii of the nanopores 601a to 601n used. The collective near-field response 411 of the nanopores 601a to 601n can be used to determine the row density of the nanostructure rows 403a to 403n of the first dispersion structure 300a. The first nanopore 601a can have a radius and the of the entire nanopores 601a to 601n

[0109]

[0110] can be similar, which can follow the following equation:

[0111] where θ can be the phase shift of the incident light 201, i is the imaginary unit, and R is the radius of the first nanopore 601a at which the light can no longer be scattered and can be approximately half of the width of the wavelength to be scattered. By determining the radii of the nanopores 601a to 601n, the density of the first dispersion structure 300a can be determined.

[0111] At a higher row density of the nanostructure rows 403a to 403n, due to the subwavelength condition, the amount of scattering of the incident light 201 can be reduced. As will be further described below, the subwavelength condition can occur when the average distance d between adjacent nanostructure rows 403a to 403n decreases from the maximum subwavelength of 1 / 2 of the target wavelength 409 to 0 nm.

[0112] The line density (including the distribution and average distance between adjacent rows of nanostructures 403a to 403n) can be determined by the target wavelength 409 of the incident light 201 that can be scattered. The maximum distance between adjacent rows of nanostructures 403a to 403n can be closer to each other than the sub-wavelength of the target wavelength 409 of the incident light 201. For example, for an 800 nm wavelength, the sub-wavelength can be 400 nm, and the maximum distance between adjacent rows of nanostructures 403a to 403n can be 400 nm. If for an 800 nm wavelength, the adjacent rows of nanostructures 403a to 403n are within 400 nm of each other, the 800 nm wavelength can be scattered. If the distance between two adjacent rows of nanostructures 403a to 403n is closer to the maximum 400 nm distance, there may be more scattering. If the distance between two adjacent random rows of nanostructures 403a to 403n is closer to 0 nm, there may be less scattering. Thus, when designing the arrangement of the rows of nanostructures 403a to 403n, the line density can affect the efficiency of scattering. Additionally, if there is a pattern in the arrangement of the rows of nanostructures 403a to 403n, the light scattering can depend on the pattern of the rows of nanostructures 403a to 403n. For example, if the rows of nanostructures 403a to 403n are evenly spaced or spaced by a repeatable pattern, the scattering of the target wavelength range can occur at a fixed angle for each wavelength and can not be scattered in the first angular range 412 or the second angular range 413. Thus, the arrangement of the rows of nanostructures 403a to 403n can be a semi-random uniform distribution using inverse transform sampling to produce a random distribution between the minimum and maximum distances.

[0113] In some embodiments, the distribution of the rows of nanostructures 403a to 403n can be determined by a probability density function The probability density function can be used to provide the boundaries for the random arrangement of each row.

[0114] In some embodiments, the Fourier transform of the probability distribution of the rows of nanostructures 403a to 403n can be written as The Fourier transform of the probability density function can be used to determine how the rows of nanostructures 403a to 403n are randomly or semi-randomly distributed. The Fourier transform can be the characteristic function for the distribution of the rows of nanostructures 403a to 403n. The Fourier transform can be used to configure the random distribution of the rows of nanostructures 403a to 403n to allow the distribution of the rows of nanostructures 403a to 403n to be as independent as possible from the scattered light 408, which can be expressed as scattered light

[0115] Using a Fourier transform for configuring a random distribution, a semi-uniform random distribution of nanostructure rows 403a to 403n can be generated such that there is no spatial correlation between adjacent nanostructure rows 403a to 403n. The lack of spatial correlation between adjacent nanostructure rows 403a to 403n can permit various angles of an angular range (angle of incidence range) 401 to allow a constant output scattering range of light within a first angular range 412 and a second angular range 413.

[0116] Specular term of transmitted light Position information of the scattered light 408 can be provided (which can be used to construct an incident image). The position information of the scattered light 408 and the chromatic scattered light 410 can permit simultaneous imaging and spectral analysis of light from the first dispersion structure 300a. In some embodiments, it can be beneficial to optimize the scattering of high-angle light for angle-independent spectroscopy.

[0117] Figure 7 A design analysis depicting a one-dimensional construction of the first dispersion structure 300a is shown. It shows an example efficiency-versus-density relationship of the first dispersion structure 300a having a target wavelength range of 700 nm to 725 nm. In some embodiments, Figure 4 the efficiency of the near-field response 411 versus Figure 6 the different total densities of the nanostructure rows 403a to 403n in

[0118] Figure 8 A top view of an example nanostructure layer 402 is depicted. The nanostructure layer 402 can include nanoantennas 801 and can serve as Figure 6 an alternative embodiment of the nanopores 601a to 601n of

[0119] Plasma materials can include metals, transparent conductive oxides, transition metal nitrides, or 2D materials. Plasma nanoantennas can interact with light through plasma resonance. During the interaction, electrons in the plasma nanoantennas may be displaced from their steady-state positions due to an external electric field, which can be referred to as polarization. The polarization of the electrons can generate an internal field to restore the electrons to their steady state. Under the influence of an external electric field, the oscillation of the electrons can occur with a phase shift of pi over the spectral width of the plasma resonance. Noble metals such as gold and silver can be used as the building materials for plasma structures. Additional modifications such as creating V-shaped nanoantennas can be utilized to support two resonance modes and include a metal ground plane separated from the nanoantenna array by a thin dielectric spacer. By adding a thin dielectric spacer, incident light can induce anti-parallel currents on the nanoantenna 801 and the ground plane, which can generate gap resonances and provide a phase shift from 0 to 2pi.

[0120] Plasma nanoantennas can be fabricated by focused ion beam milling. A thin layer of metal can be milled from a focused ion beam to produce a plasma nanoantenna structure. The nanoantenna 801 can also be a dielectric nanoantenna or a dielectric nanopore. Dielectric nanoantennas or nanopores can manipulate light through Mie scattering. Electron beam (e-beam) lithography and electron beam evaporation can also be used to fabricate dielectric nanoantennas.

[0121] Figure 9 A graph is depicted showing an example of the dispersion efficiency of light at various wavelengths for an embodiment of the dispersion array 204 for Figure 2 The efficiency response for the first wavelength band can be response 901a, and response 901a can correspond to the first dispersion structure 300a. Subsequent responses 901b to 901n can be associated with subsequent dispersion structures 300b to 300n. Figure 9 Can be used to configure and verify Figure 6 the efficiency of the dispersion structures 300a to 300n and their corresponding rows of nanostructures 403a to 403n. Additionally, this efficiency can be used to calibrate the dispersion structures 300a to 300n. This efficiency can also be used for spectroscopic purposes. When an image is read by the Figure 2 sensor 200, the spectral response portion can be interpreted by referring to an efficiency graph such as Figure 9 the one shown.

[0122] In this example, the dispersion array 204 can include n = 8 dispersion structures 300a to 300n that can cumulatively provide a dispersion efficiency for light in the approximate wavelength range of 700 nm to 900 nm. Figure 3 The dispersion structures 300a to 300n for

[0123] Figure 10 depicts the angular-intensity dispersion curves of the chromatic light 410 of various dispersion output angles θ generated by an exemplary embodiment of a dispersion structure such as 300a to 300n. The shown wavelength-dependent dispersion angles can be used when designing Figure 4 the parameters of the nanostructured layer 402 (e.g., when designing a specific dispersion structure such as 300a), and can also be used to design the image sensor 206. In one example, Figure 4 the angular-intensity dispersion of the first dispersion structure 300a can be shown, and the target wavelength range of the chromatic light 410 is between 800 nm and 835 nm. The wavelength of 835 nm can pass through the exemplary first dispersion structure 300a with 0° dispersion. The dispersion output angles θ of approximately + / -30° can correspond to the wavelength range of 800 nm to 835 nm, which can be the second angular range 413. In one embodiment, the second angular range 413 can be used for spectral analysis. In another embodiment, the first angular range 412 can be the wavelength for imaging rather than for spectral analysis. The first angular range 412 can be + / -15°. The spectral reading angular range 414 can be from + / -15° to + / -30°. Figure 10 For other dispersion structures (such as 300b to 300n), there can be chromatic light 410 with different target wavelength ranges, and thus, different wavelengths can be dispersed at a specific angle (e.g., + / -30°).

[0124] From a design perspective, the dispersion angle for each wavelength can be fitted to an exponentially broadened Lorentzian distribution, resulting in a curve similar to the

[0125] curve graph in Figure 10 .

[0126] The peak position with respect to the wavelength can be extracted from the fit of the exponentially broadened Lorentzian distribution. Then, the peak position can be fitted to the following equation to extract the target wavelength 409 for the chromatic light 410 and the refractive index n* for the filter layer 404. For the following calculations, the full width at half maximum (FWHM) of the fit of the dispersion angle and wavelength can be considered to determine the characteristics of the first dispersion structure 300a. The dispersion angle of the chromatic light 410 can depend on the target wavelength 409 (λ0) of the chromatic light 410 and the refractive index n* of the filter layer 404:

[0127]

[0128] In some embodiments, this peak position can be used to determine the target wavelength 409 of the chromatic light 410, which can be used to generate the dispersion array 204 having the dispersion structures 300a to 300n.

[0129] Figure 11Depicts a view from the side Figure 2 The incident light 201 passes through the image sensor 206. Figure 2 The aperture 202 and dispersion array 204 (and possibly lens 205) of the image sensor 206 enter from the center of the image sensor 206 and define a central axis through the center of the image sensor 206, and the aperture 202 and dispersion array 204 (and possibly lens 205) are located at a specific height from the image sensor 206 (off the page). The image sensor 206 includes an inner region 208 and an outer region 209, each of the inner region 208 and the outer region 209 including a corresponding plurality of pixels. The inner region 208 includes a first group of pixels within a first angular range 412 from the axis of the incident light 201 traveling from the dispersion array 204 and the lens 205, and the outer region 209 includes a second group of pixels within a larger second angular range 413 from the axis of the incident light 201 traveling from the dispersion array 204 and the lens 205 and not yet included by the inner region 208. As will be described in detail in FIG. Figure 12 As shown pictorially in FIG. 2 , the inner region 208 and the outer region 209 of the image sensor 206 may be viewed from Figure 3 The dispersion structures 300a to 300n read imaging data and spectral data.

[0130] More specifically, in some embodiments, the inner region 208 may be used to image the scattered light 408, and the outer region 209 may be used to read the spectrum of the dispersed light 410. In some embodiments, the inner region 208 may be a group of pixels logically grouped as a circle, and the outer region 209 may be a group of pixels logically grouped together as a ring coaxial with the inner region 208. In other embodiments, the inner region 208 and the outer region 209 may be used together to read only spectral data.

[0131] More specifically, recall that filter layer 404 can allow certain wavelengths of light (e.g., scattered light 408) within a first angular range 412 and dispersed light 410 of a selected set of different wavelengths within a second angular range 413 to pass without dispersion, and that the precise dispersion angle is based on the wavelength of the light. Thus, spectral reading can be accomplished using sensor pixels in outer region 209 since only wavelength-dependent angularly dispersed light reaches these pixels.

[0132] Because the inner region 208 receives light that has undergone reduced scattering and contains only a portion of the dispersed light 410, the inner region 208 can read imaging data from all of the received light falling within it.

[0133] For example, if the first angular range 412 is from 0° to + / -15° and the second angular range 413 is from 0° to + / -30°, the inner region 208 can image visible light in the range from 0° to + / -15°, and the outer region 209 can read the dispersed NIR light in the range from + / -15° to + / -30°.

[0134] Figure 12 A composite image 1201 that can be illuminated by incident light 201 is depicted. In one embodiment, the incident light 201 can include visible broadband light or NIR broadband light.

[0135] The composite image 1201 with a center can be seen, and the center has stripes radially diverging from the center towards the edges. For illustrative purposes, the composite image 1201 can be in false color. The composite image 1201 can be a false-color representation of an image captured by a monochromatic sensor, and the color can represent the intensity or brightness of the image. Due to both the scattering of light (scattered light 408) and the dispersion of light (dispersed light 410), the composite image 1201 may appear blurred. The stripes (such as 1204) can be the result of the scattering of light along a single axis from a single dispersion structure among the dispersion structures (light dispersion mechanisms) 300a to 300n.

[0136] Referring to Figure 3 , each of the dispersion structures 300a to 300n can scatter and disperse light in one dimension. For example, the dispersion structures 300a to 300n can scatter and disperse light along an axis perpendicular to the dispersion structures 300a to 300n including the rows of nanostructures 403a to 403n. Since each of the dispersion structures 300a to 300n is at a different angle from the other dispersion structures 300a to 300n, each of the dispersion structures 300a to 300n generates its own unique stripes in a defined orientation corresponding to the arrangement of the dispersion structures 300a to 300n within the dispersion array 204. Figure 12 n = 8 dispersion structures 300a to 300n can be depicted, where the stripes of the scattered light and the dispersed light shown in the composite image 1201 are each separated by 22.5° from one another, and the stripes each correspond to the dispersion structure angles 301a to 301n.

[0137] Each of the dispersion structures 300a to 300n can be configured (as discussed above, based in part on their respective target wavelengths 409 and the dimensions of their defect layers 407) to disperse incident light 201 within a defined set of target wavelength ranges. As previously discussed, each of the dispersion structures 300a to 300n can produce a unique linear fringe of dispersed spectral light (such as fringe 1204 for the first dispersion structure 300a). Additionally, as discussed above, due to the physical connection of the dispersion array 204 to the image sensor 206, each fringe can occur at a unique known position and orientation. Finally, within each fringe, each specific wavelength will be dispersed at a known angle corresponding to a known distance from the image center. Thus, light of each wavelength received across the entire target wavelength range of the dispersion array 204 can fall on a known region of the image sensor 206 and thus on known pixels. Based on this information, an accurate determination of the spectral composition and intensity of a given optical signal can be made based on the signals received from those pixels.

[0138] After the composite image 1201 is read by the image sensor 206, the image 1202 and spectral data 1203 can be extracted. In one embodiment, the image 1202 can be a visible image, and the spectral data 1203 can be an NIR spectrum. Post - processing algorithms can be applied to extract the image 1202 and spectral data 1203.

[0139] To reconstruct the image, post - image processing can be used to remove artifacts caused by scattering. In some embodiments, this can involve applying a de - blurring algorithm based on the calibration of the dispersion structures 300a to 300n. In some embodiments, this can involve measuring the point - spread function (PSF) by measuring the transmitted angular intensity of light through each of the dispersion structures 300a to 300n when illuminated by collimated visible light (400 nm to 650 nm). The Richardson - Lucy algorithm can be used to de - convolve the measured point - spread function (PSF) from the original image. Ten iterations can be used to provide a balance between de - blurring and avoiding ringing artifacts.

[0140] To reconstruct the measured spectrum, in some embodiments, the following process can be utilized. The spectrum can be extracted from the spectral region of the raw data by fitting the raw data to an ideal model of the wavelength - dependent scattering fringes of the dispersion structures 300a to 300n. When the incident light 201 impinges on the dispersion structures 300a to 300n, first, the incident light 201 can be scattered into different angles according to the orientation of the first dispersion structure 300a and the initial angle of the light. Second, the light can be filtered and dispersed at a set of angles according to the spectral content (e.g., wavelength) of the light.

[0141] Therefore, it is possible to model the scattering intensity distribution g(θ x , θ y and the positions x, y on the detector with respect to the incident light angle θ x , θ y , x, y). The ideal dispersion structures 300a to 300n can scatter the incident light equally to all pixels along their dispersion structure angles 301a to 301n. Therefore, g can be defined as:

[0142]

[0143] where f can be the focal length of the focusing lens and θ can be the angle of the axis orientation of the dispersion structures 300a to 300n. For a given image, the total scattering intensity distribution can be written as:

[0144] g′(x, y) = ∫∫α(θ x , θ y )g(θ x , θ y , x, y )dθ x dθ y .

[0145] where α(θ x , θ y ) is the intensity distribution of the image as an input parameter in the model.

[0146] Next, the filtering effect at different angles with spectral intensity I(λ) can be described. For the first dispersion structure 300a, only the target wavelength range of the chromatic light 410 (which can be called λ R (θ)) for a given angle θ can be transmitted at the given angle. Therefore, we can define the spectral filtering function at the pixel positions x, y as:

[0147] S(x, y) = ∫I(λ)·δ(λ R (θ eq (x, y)) - λ)dλ = I(λ R (θ eq (x, y))).

[0148] where, for the optical system, θ eq (x, y) can be the angle corresponding to the pixel positions x, y, which can be written as:

[0149]

[0150] Finally, the full fringe pattern of the dispersion structures 300a to 300n can be calculated by multiplying the spectral filtering by the random scattering to obtain the final spectral fringe pattern:

[0151] SP(x, y) = g′(x, y)·S(x, y).

[0152] The same calculation can be repeated for each of the n dispersive structures 300a to 300n, and then the intensity patterns can be added together to obtain a final spectral fringe pattern from the model.

[0153] To calculate the spectrum from the measured fringe pattern, in some embodiments, a least squares fitting method (LSQR) with a tolerance of, for example, 10 -6 can be used to fit the obtained model to the raw data.

[0154] As described above, the ideal dispersive structures 300a to 300n are considered to have angle-independent scattering and transmission efficiencies. However, in practice, due to the fact that scattering can be completely random, slight intensity variations with respect to the angle can be observed. Additionally, due to Fresnel reflection, light at higher angles may pass through the filter with lower efficiency than light at lower angles. Moreover, the transition from one dispersive structure 300a to 300n to another with respect to the wavelength can lead to additional errors. To correct for this, a wavelength-dependent calibration term is multiplied across the entire spectrum:

[0155] I′(λ) = c′(λ)I(λ).

[0156] Where I′ is the calibrated spectral intensity and c′ is the calibration factor. To calculate c′, the spectrum measured using a high-resolution commercial spectrometer can be divided by the spectrum I(λ) measured by the dispersive structures 300a to 300n for the incident unfiltered light. Then this factor can be used to calculate the spectrum using the dispersive structures 300a to 300n, showing good agreement with the measurements of the reference spectrometer.

[0157] Since the calibration takes into account the non-constant scattering of the dispersive structures 300a to 300n, it can vary according to the angle of incidence of the light and thus can vary according to the incident image of the light. Therefore, a separate calibration matrix for c′(λ) for each angle of incidence can be measured and used for each image used. However, in a more general setting where the image is not known a priori, the linearity of the system can be utilized to calculate the calibration factor for any image, as shown by the following formula:

[0158] I single-point (λ) = f(g(θ x , θ y , x, y )),

[0159] I′(λ) = c(θ x , θ y , λ)I single-pointψ(λ) = c(θ x ,θ y ,λ) f(g(θ x ,θ y ,x,y)).

[0160]

[0161] Finally, using the definition of the calibration factor, the total calibration factor c' can be calculated:

[0162]

[0163] Thus, if a pre - calibration is performed to measure c(θ x ,θ y ,λ), then the total calibration factor c'(λ) can be calculated for any arbitrary incident image using the dispersion structures 300a to 300n. Once fully calibrated (such as after factory production), the sensor 200 including the dispersion array 204 including the dispersion structures 300a to 300n can be used to measure the spectrum in the field.

[0164] Figure 13 Illustrates a manufacturing process 1300 of the dispersion array 204. More specifically, it illustrates the process for forming the structures 510 to 515 graphically shown in Figure 5 . The manufacturing process 1300 can be a monolithic process.

[0165] Referring to Figure 4 and Figure 5 , the first process 1301 can include depositing a first layer 405 on top of a substrate 501. The first layer 405 can include a first material. In one embodiment, the first layer 405 can be TiO₂ and can be deposited by sputtering, but other materials and deposition techniques can also be used. TiO₂ sputtering can be reactive sputtering, magnetron sputtering, rf magnetron sputtering or other techniques. Other deposition techniques include, but are not limited to, sol - gel method, pulsed laser deposition, molecular beam epitaxy, and atomic layer deposition.

[0166] The second process 1302 can include depositing a second layer 406 onto the first layer 405 as described above. In one embodiment, the second layer 406 can be SiO₂ and can be deposited by PECVD or SiO₂ sputtering, but other materials and deposition techniques can also be used.

[0167] The third process 1303 may include depositing alternating first layers 405 and second layers 406 after the second process 1302. That is, the first process 1301 and the second process 1302 may be repeated multiple times one after the other to construct an alternating series of first layers 405 and second layers 406, thereby producing a desired number of first layers 405 and second layers 406. Figure 5 The materials and designs of the first layer 405 and the second layer 406 are described.

[0168] The fourth process 1304 may deposit a defect preparation layer 504. In one embodiment, the defect preparation layer 504 may be SiO2 and may be deposited by PECVD, but other materials and deposition techniques may also be used. In one embodiment, the defect preparation layer 504 may be a thicker layer of SiO2. The thickness of the defect preparation layer 504 may be determined by the thickness of the defect layer 407 desired after processing the defect preparation layer 504.

[0169] The fifth process 1305 may include depositing one or more defect lithography layers 503 onto the defect preparation layer 504 after the fourth process 1304. The defect lithography layer 503 may be a photoresist and may be a polymer.

[0170] The sixth process 1306 may apply UV exposure to the defective photoresist layer 503 and may also penetrate to the defective preparation layer 504. Figure 5 UV irradiation is applied over a range 508 of, and the total dose of UV exposure can vary over the range 508. Variable dose power or variable time dose UV exposure can be applied, which can form a defect layer 407 of variable thickness. For example, the variable dose power level for 8 partitions can have power levels of x, 7 / 8x, 6 / 8x, ..., as low as 1 / 8x power level. The variable time dose UV exposure can have the same power level x, and can have time t, 7 / 8t, 6 / 8t, ..., as low as 1 / 8t for each partition. The fifth process 1305 and the sixth process 1306 together can be referred to as grayscale lithography technology, but other techniques can be used.

[0171] The seventh process 1307 may include etching of the defective lithography layer 503 and the defective preparation layer 504. In one embodiment, dry etching may be used, wherein a focused electron beam may bombard the defective lithography layer 503 and the defective preparation layer 504 to form the defective layer 407. Other etching techniques may be used. The defective layer 407 may have a variable thickness (after the subsequent process steps described above), and may allow dispersion of light with variable wavelengths due to its different thicknesses. In one embodiment, the defective layer 407 may have a thickness of eight steps, and the eight different thickness layers may allow dispersion of wavelengths with sub-bands of two nanometers to five nanometers.

[0172] In an alternative embodiment, as discussed with respect to Figure 5 multiple rounds of etchant masking and etching may be performed to generate the defect layer 407 from the defect preparation layer 504.

[0173] The eighth process 1308 may include depositing the first layer 405 onto the defect layer 407 using the same techniques described in the first process 1301. The first layer 405 may include the same materials as in the first process 1301, and its thickness may be the same or may vary.

[0174] The ninth process 1309 may include depositing the second layer 406 using the same techniques described in the second process 1302. The second layer 406 may include the same materials as in the second process 1302, and its thickness may be the same or may vary.

[0175] The tenth process 1310 may include alternately depositing the first layer 405 and the second layer 406 of the eighth process 1308 and the ninth process 1309 one or more times (i.e., to produce the desired number of repeating layers including the first layer 405 and the second layer 406) according to the desire.

[0176] The eleventh process 1311 may include depositing the cap stack 506. In one embodiment, the cap stack 506 may include the materials of the first layer 405 and may be deposited for a longer period of time using the first process 1301. The cap stack 506 may be TiO2 and may be deposited by a sputtering method. The cap stack 506 may be significantly thicker than the first layer 405 and the second layer 406 and may be level with the initial layer / substrate to allow nanostructures to be generated therein.

[0177] The twelfth process 1312 may include depositing the photolithography mask 507 onto the cap stack 506. The photolithography mask 507 may be a photoresist and may be a polymer.

[0178] The thirteenth process 1313 may apply irradiation to the photolithography mask 507 and may also penetrate into the cap stack 506. The irradiation may be electron beam (e-beam) lithography, UV exposure, or other irradiation. The irradiation may be applied to the photolithography mask 507, and the total dose of the irradiation may follow the pattern to generate nanopores 601a to 601n as shown in Figure 6 . A variable dose power or a variable time dose of irradiation may be applied to form the nanopores 601a to 601n.

[0179] The fourteenth process 1314 may include the etching of the photolithography mask 507 and the capping stack 506. In one embodiment, dry etching may be used, wherein a focused electron beam may bombard the photolithography mask 507 and the capping stack 506 to form nanopores 601a to 601n. Other etching techniques may be used.

[0180] Embodiments of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware (including the structures disclosed in this specification and their structural equivalents), or in combinations of one or more of the foregoing. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs (i.e., one or more modules of computer program instructions) encoded on a computer storage medium for execution by, or to control the operation of, a data processing apparatus. Optionally or additionally, the program instructions can be encoded on an artificially generated propagated signal (e.g., a machine-generated electrical, optical, or electromagnetic signal) that is generated to encode information for transmission to an appropriate receiver apparatus for execution by the data processing apparatus. A computer storage medium can be a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof, or be included in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof. Moreover, although a computer storage medium is not a propagated signal, a computer storage medium can be the source or destination of computer program instructions encoded in an artificially generated propagated signal. A computer storage medium can also be one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices), or be included in one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). Additionally, the operations described in this specification can be implemented as operations performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources.

[0181] Although this specification may include many specific implementation details, these implementation details should not be construed as limitations on the scope of any claimed subject matter, but rather should be construed as descriptions of features specific to particular embodiments. Certain features described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented separately in multiple embodiments or in any suitable sub-combination. Moreover, although the features may be described above as acting in certain combinations and even initially claimed as such, in some cases one or more features from a claimed combination can be deleted from the combination, and the claimed combination can be directed to a sub-combination or a variation of a sub-combination.

[0182] Similarly, although operations are depicted in the drawings in a particular order, this should not be construed as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the foregoing embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0183] Accordingly, specific embodiments of the subject matter have been described herein. Other embodiments are within the scope of the claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve desirable results. In certain embodiments, multitasking and parallel processing may be advantageous.

[0184] As those skilled in the art will recognize, the innovative concepts described herein can be modified and varied over a wide range of applications. Accordingly, the scope of the claimed subject matter should not be limited to any of the particular example teachings discussed above, but is defined by the claims.

[0185] Embodiments of the inventive concept can be extended to the following statements, but are not limited thereto:

[0186] Statement 1: A sensor, comprising: an aperture, a dispersion array, a lens, an image sensor, and a processor.

[0187] Statement 2: The sensor according to Statement 1, wherein the dispersion array further comprises one or more dispersion structures capable of scattering light in a first wavelength range and dispersing light in a second wavelength range.

[0188] Statement 3: The sensor according to Statement 2, wherein at least two of the dispersion structures comprise defect layers, and wherein the defect layers of the at least two dispersion structures have different thicknesses from each other.

[0189] Statement 4: The sensor according to Statement 3, wherein the dispersion structures comprise the at least two dispersion structures that disperse light having different wavelength ranges from each other.

[0190] Statement 5: The sensor according to Statement 3, wherein the dispersion structure scatters light in a first direction, but allows light to pass substantially through in a second direction without scattering.

[0191] Statement 6: The sensor according to Statement 3, wherein the at least two dispersion structures include rows of nanostructures positioned at different angles from each other.

[0192] Statement 7: The sensor according to Statement 3, wherein the at least two dispersion structures include rows of nanostructures positioned at the same angle from each other.

[0193] Statement 8: The sensor according to Statement 1, wherein the image sensor reads spectral data from light of wavelengths dispersed by the dispersion array.

[0194] Statement 9: The sensor according to Statement 8, wherein the processor can reconstruct a spectrum based on the spectral data.

[0195] Statement 10: The sensor according to Statement 1, wherein the image sensor is logically subdivided to read image data from a first set of pixels and spectral data from a second set of pixels.

[0196] Statement 11: The sensor according to Statement 10, wherein the first set of pixels includes circles and the second set of pixels includes rings coaxial with the circles of the first set of pixels.

[0197] Statement 12: The sensor according to Statement 10, wherein the processor can reconstruct an image based on the image data or reconstruct a spectrum based on the spectral data.

[0198] Statement 13: The sensor according to Statement 1, wherein the dispersion array provides a constant range of scattering angles and a constant range of dispersion angles for incident light input within an incident light input angle range.

[0199] Statement 14: The sensor according to Statement 1, wherein the incident light input angle range is between 0° and + / -30°.

[0200] Statement 15: The sensor according to Statement 2, wherein the range of scattering and dispersion angles is between 0° and + / -15° for a first wavelength range and between 0° and + / -30° for a second wavelength range.

[0201] Statement 16: The sensor according to Statement 1, wherein the lens can be a metalens.

[0202] Statement 17: The sensor according to Statement 1, wherein the aperture, the dispersion array, and the lens are integrated together.

[0203] A method of obtaining data from a sensor, comprising the steps of: receiving incident light, scattering the incident light through a scattering layer to produce scattered light, dispersing a subset of the scattered light through a dispersion layer to produce dispersed light, receiving the dispersed light on an image sensor, and reconstructing spectral data based on the dispersed light.

[0204] Statement 19: The method according to statement 18, wherein the incident light comprises light from the visible spectrum or the near-infrared (NIR) spectrum.

[0205] Statement 20: The method according to statement 18, the method further comprising the steps of: receiving scattered light on an image sensor; and reconstructing an image based on the scattered light.

[0206] Statement 21: The method according to statement 18, wherein the spectral data comprises light from the NIR spectrum.

[0207] Statement 22: The method according to statement 18, wherein the incident light is scattered by a scattering layer comprising a nanostructured surface.

[0208] Statement 23: The method according to statement 18, wherein the subset of the scattered light is dispersed by a distributed Bragg filter.

[0209] Statement 24: The method according to statement 18, wherein the image data and the spectral data are reconstructed simultaneously.

[0210] Statement 25: A dispersion array, the dispersion array comprising: at least one dispersion structure that disperses light in a target wavelength range starting from 0° dispersion of a target wavelength, wherein the dispersion structure further comprises: a nanostructured layer; and a filter layer.

[0211] Statement 26: The dispersion array according to statement 25, wherein the nanostructured layer comprises nanopores, nanorods, or nanoantennas.

[0212] Statement 27: The dispersion array according to statement 25, wherein the nanostructured layer is a dielectric material or a plasmonic material.

[0213] Statement 28: The dispersion array according to statement 25, wherein the dispersion structure is adjusted to scatter and disperse light associated with the target wavelength range.

[0214] Statement 29: The dispersion array according to statement 25, wherein the nanostructured layer further comprises nanostructured rows, wherein each nanostructured row is parallel to each other.

[0215] Statement 30: The dispersion array according to statement 29, wherein each nanostructured row further comprises nanopores.

[0216] Statement 31: The dispersion array according to statement 30, wherein the nanopores are located in a TiO2 layer.

[0217] Statement 32: The dispersion array according to Statement 30, wherein the radius of the nanopore is half or less of the target wavelength within the target wavelength range of the dispersion structure.

[0218] Statement 33: The dispersion array according to Statement 30, wherein each nanopore is spaced close enough within the nanostructure row to allow the target wavelength range to pass through the nanostructure row in one dimension with little or no scattering.

[0219] Statement 34: The dispersion array according to Statement 29, wherein the nanostructure rows are distributed between a minimum distance and a maximum distance.

[0220] Statement 35: The dispersion array according to Statement 34, wherein the nanostructure rows are randomly distributed between the minimum distance and the maximum distance.

[0221] Statement 36: The dispersion array according to Statement 34, wherein the maximum distance between the nanostructure rows is half of the length of the longest wavelength within the target wavelength range of the dispersion structure.

[0222] Statement 37: The dispersion array according to Statement 25, wherein the filter layer includes a distributed Bragg reflector, a dielectric mirror, a fiber Bragg grating, or a semiconductor Bragg mirror.

[0223] Statement 38: The dispersion array according to Statement 25, wherein the filter layer includes at least a first layer of a first thickness and a first material and a second layer of a second thickness and a second material, and the first layer and the second layer are alternately stacked on top of each other to form a stacked layer.

[0224] Statement 39: The dispersion array according to Statement 38, wherein the first layer includes TiO2 and the second layer includes SiO2.

[0225] Statement 40: The dispersion array according to Statement 38, wherein there are at least two sets of stacked layers.

[0226] Statement 41: The dispersion array according to Statement 38, wherein the stacked layer can disperse light of the target wavelength of the dispersion structure.

[0227] Statement 42: The dispersion array according to Statement 38, wherein the dispersion array includes two or more dispersion structures, and at least one dispersion structure includes a defect layer.

[0228] Statement 43: The dispersion array according to Statement 42, wherein the dispersion array includes a plurality of dispersion structures with defect layers, and at least two dispersion structures have defect layers of different thicknesses.

[0229] Statement 44: A method of fabricating a dispersive array, the method comprising the steps of: depositing a first filter stack on a substrate; depositing a defect layer; depositing a second filter stack; depositing a cap stack; and forming nanostructures from the cap stack.

[0230] Statement 45: The method according to Statement 44, wherein the step of depositing the first filter stack comprises depositing a first layer composed of at least one first material and a second layer composed of at least one second material.

[0231] Statement 46: The method according to Statement 45, wherein the first material is a dielectric material having a refractive index between 1.6 and 2.7.

[0232] Statement 47: The method according to Statement 45, wherein the second material is a dielectric material having a refractive index between 1.3 and 1.6.

[0233] Statement 48: The method according to Statement 44, wherein a gray-scale lithography technique is used to etch the defect layer.

[0234] Statement 49: The method according to Statement 44, wherein the defect layer comprises materials used in the first filter stack.

[0235] Statement 50: The method according to Statement 44, wherein the nanostructures are formed by electron beam lithography or photolithography.

[0236] Statement 51: The method according to Statement 44, wherein the nanostructures are formed as one or more dispersive structures.

[0237] Statement 52: The method according to Statement 51, wherein for a plurality of dispersive structures, the defect layer is etched to different thicknesses.

Claims

1. A sensor, the sensor comprising: An aperture; A dispersion array, including a dispersion structure, the dispersion structure being adjusted to scatter and disperse light associated with a target wavelength range; A lens; An image sensor; And A processor, Wherein, the image sensor is subdivided into reading image data from a first group of pixels and reading spectral data from a second group of pixels, wherein, the spectral data is reconstructed according to the dispersed light, the image data is reconstructed according to the scattered light, wherein, the first group of pixels includes circles, and the second group of pixels includes rings coaxial with the circles of the first group of pixels.

2. The sensor according to claim 1, wherein, The dispersion array includes one or more dispersion structures, the dispersion structure being capable of scattering light in a first wavelength range and dispersing light in a second wavelength range.

3. The sensor according to claim 2, wherein, When the dispersion array includes multiple dispersion structures, at least two dispersion structures include defect layers, wherein, the defect layers of the at least two dispersion structures have different thicknesses from each other.

4. The sensor according to claim 3, wherein, The at least two dispersion structures disperse light with different wavelength ranges from each other.

5. The sensor according to claim 3, wherein, The at least two dispersion structures scatter light in a first direction, but allow light to pass through substantially without scattering in a second direction.

6. The sensor according to claim 3, wherein, The at least two dispersion structures include rows of nanostructures positioned at different angles from each other.

7. The sensor according to claim 3, wherein, The at least two dispersion structures include rows of nanostructures positioned at the same angle from each other.

8. The sensor according to claim 1, wherein, The image sensor reads spectral data from light of wavelengths dispersed by the dispersion array.

9. The sensor according to claim 8, wherein The processor is configured to reconstruct a spectrum according to the spectral data.

10. The sensor according to claim 1, wherein The processor is configured to reconstruct an image according to the image data or reconstruct a spectrum according to the spectral data.

11. The sensor according to any one of claims 1 to 10, wherein, The dispersion array provides a constant range of scattering and dispersion angles for incident light input within an incident light input angle range.

12. The sensor according to any one of claims 1 to 10, wherein, The incident light input angle range is between 0° and + / -30°.

13. The sensor according to claim 2, wherein, The range of scattering and dispersion angles is between 0° and + / -15° for the first wavelength range, and between 0° and + / -30° for the second wavelength range.

14. The sensor according to any one of claims 1 to 10, wherein, The lens is a meta-lens.

15. The sensor according to any one of claims 1 to 10, wherein, The aperture, the dispersion array and the lens are integrated together.

16. A method for obtaining spectral data from a sensor, the method comprising: Receiving incident light; Scattering the incident light through a scattering layer to produce scattered light; Dispersing a subset of the scattered light through a dispersion layer to produce dispersed light; Receiving the dispersed light on an image sensor; Reconstructing spectral data according to the dispersed light, Receiving the scattered light on an image sensor; and Reconstructing image data according to the scattered light, Wherein, the image sensor is subdivided into reading image data from a first group of pixels and reading spectral data from a second group of pixels, Wherein, the first group of pixels includes circles, and the second group of pixels includes rings coaxial with the circles of the first group of pixels.

17. The method according to claim 16, wherein The incident light includes light from the visible spectrum or the near-infrared spectrum.

18. The method according to claim 17, wherein, The spectral data is reconstructed according to the dispersed light from the near-infrared spectrum.

19. The method according to any one of claims 16 to 18, wherein The incident light is scattered through a scattering layer including a nanostructured surface.

20. The method according to any one of claims 16 to 18, wherein, The subset of the scattered light is dispersed through a distributed Bragg filter.

21. The method according to any one of claims 16 to 18, wherein The image data and the spectral data are reconstructed simultaneously.

Images