Integrated apparatus, imaging system, and method for wavelength-dependent detection of light

Abstract

An integrated device for wavelength-dependent detection of light is provided, comprising: an optical focusing element having a focusing end and an output end, wherein the optical focusing element is configured to focus incident light at the focusing end and concentrate the light at the output end, forming an extension from a light-receiving end to a light-distributing end, and surrounded along the extension by a host medium, wherein the output end is coupled to the light-receiving end, the waveguide is configured to receive light from the optical focusing element at the light-receiving end, the waveguide and host medium are configured to propagate light to form a light pattern at the light-distributing end, the distribution of the light pattern across the light-distributing end depends on the wavelength of light, and a plurality of photosensitive elements are arranged so as to receive different portions of the light pattern at the light-distributing end for wavelength-dependent detection of light.

Description

[Technical Field]

[0001] This specification relates to multispectral detection of light, and more specifically, to an integrated apparatus, imaging system, and method for wavelength-dependent detection of light. [Background technology]

[0002] Photodetectors and image detectors are essential solid-state components in systems that convert light into electrical signals. In particular, detectors for detecting several wavelength bands of light within the ultraviolet, visible, and infrared spectral ranges have found a wide range of applications, from consumer electronic cameras and smartphones to environmental sensing in automobiles and other scientific and industrial applications.

[0003] A particularly important instrument parameter for image detectors is spatial resolution, which is related to the size of each photosensitive element or pixel. For example, smaller pixels can result in higher camera resolution. At the same time, since wavelength and absorption length remain constant despite pixel shrinkage, pixel downscaling leads to decreased light sensitivity, increased noise, and increased spatial light crosstalk.

[0004] To distinguish light of different wavelengths, imaging devices such as digital cameras typically feature filter arrays, such as absorbing Bayer color filter arrays, that cover the pixels. A common example is a photographic camera, where color filters are integrated onto the pixel array under microlenses to distinguish different colors. However, due to the absorbing nature of color filters, approximately two-thirds of the light entering the pixels is absorbed and lost during the filtering process.

[0005] Furthermore, pixel reduction requires a reduction in the thickness of the color filter. The reduction in pixel size limits the effective use of microlens arrays, affecting spatial resolution when the pixel size is smaller than the microlens' circle of confusion. It is also important to consider the limitations on the fabrication size of microlenses, and the fact that the ability of microlenses to concentrate and focus light decreases as the lens diameter approaches the wavelength.

[0006] Therefore, in this technical field, further improvements are needed regarding the photosensitivity of photodetectors and imaging devices related to multispectral light detection, and consequently, downscaling. [Overview of the project]

[0007] The object of this specification is to mitigate, mitigate, or eliminate, individually or in any combination, one or more of the defects and shortcomings identified above in the art. These and other objects are at least partially satisfied by the invention as defined in the independent claims. Preferred embodiments are described in the dependent claims.

[0008] According to the first embodiment, an integrated device for wavelength-dependent detection of light is provided, and this integrated device is A light-gathering element having a light-gathering end and a light-transmitting end, wherein the light-gathering element is configured to gather incident light at the light-gathering end and concentrate the light at the light-transmitting end. A waveguide is placed within a host medium, and the waveguide is a multimode waveguide, forming an extension from the light-receiving end to the light-distributing end, surrounded along the extension by the host medium, the transmitting end of the light-gathering element is directly coupled to the light-receiving end of the waveguide, the waveguide is configured to receive light from the light-gathering element at the light-receiving end, the waveguide and host medium are configured to propagate light to form a light pattern at the light-distributing end, and the distribution of the light pattern across the region within the host medium and waveguide at the light-distributing end depends on the wavelength of the light. Multiple photosensitive elements, in order to detect wavelength-dependent light, are arranged so that different photosensitive elements receive different portions of the light pattern at the light distribution end, It is equipped with.

[0009] The term "wavelength-dependent detection" as used herein refers to the detection of light such that information related to the wavelength of the light is detected. Typically, light of different wavelengths propagates along different paths such that different wavelengths are incident on different photosensitive elements. A single device may be used for wavelength-dependent detection of light at a given point. It is conceivable that a single device may be used as an independent device for such detection of light at a given point. However, it is equally conceivable that multiple devices may be arranged in an array such as rows and columns, with different devices configured to detect light at different points in space. According to this arrangement, wavelength-dependent imaging may be provided.

[0010] In this context, the term "light" should not be limited to visible electromagnetic radiation, but should be interpreted in a broader sense. Rather, the term "light" could include, for example, ultraviolet light, infrared light, or a combination thereof.

[0011] The light-gathering element is configured to focus incident light at the focusing end and propagate the focused light to the output end. The light-gathering element is further configured to concentrate light at the output end. The light-gathering element may have a linear shape along the extension from the focusing end to the output end, or, alternatively, a tapered or flared shape along the extension from the focusing end to the output end. For example, the light-gathering element may be shaped so that light can be concentrated into a very small area at the output end having a size on the order of the wavelength of light. For example, the output end may have a width of about 340 nm. As a further example, the width of the focusing end may be about 220 nm.

[0012] Typically, the cross-section of a light-gathering element is square, but it is conceivable that the cross-section of a light-gathering element could be other shapes, such as rectangles, triangles, circles, or ellipses. Therefore, the light-gathering element as a whole may have a cylindrical, spherical, hemispherical, cubic, pyramidal, or any other suitable shape.

[0013] The light focusing element may be configured to concentrate light at the transmitting end, and therefore at or near the receiving end of the waveguide. According to this configuration, light can be coupled from the light focusing element into the waveguide so that specific modes can be excited within the waveguide.

[0014] As a non-limiting example, a light-gathering device may take the form of a dielectric microdevice. A light-gathering device may be configured to focus light by providing a photonic nanojet.

[0015] It should also be understood that the optical focusing element may be placed within a host medium. The host medium surrounding the optical focusing element may be the same type as the host medium surrounding the waveguide, or alternatively, a different type. Alternatively, the optical focusing element may not have a host medium surrounding it. In such cases, the optical focusing element may instead be surrounded by the ambient medium of the environment in which the device is located. The ambient medium is not part of the device itself, but can function as a host medium. For example, such an ambient medium surrounding an optical focusing element may be ambient air.

[0016] A waveguide placed within a host medium is configured to receive light from the transmitting end of a light-gathering element at its receiving end. In order to couple all the light focused at the receiving end into the waveguide, the light-gathering element is configured such that the transmitting end of the light-gathering element has a cross-section no larger than the cross-section of the receiving end of the waveguide. Typically, the transmitting end of the light-gathering element has a cross-section smaller than the cross-section of the receiving end of the waveguide.

[0017] The transmitting end of the light-gathering element may be directly coupled to the receiving end of the waveguide. The receiving end may be in direct physical contact with the transmitting end. Alternatively, a gap may be formed between the receiving end and the transmitting end. Another alternative is that the light-gathering element and the waveguide may be fabricated from a single piece of material, such that the light-gathering element and the waveguide are different parts of a single piece of material.

[0018] For example, one or more additional layers may be provided between the transmitting end and the receiving end. One or more additional layers may enhance the coupling of light between the light focusing element and the waveguide.

[0019] The waveguide and host medium are further configured to propagate light from the light-receiving end to the light-distributing end. The light-distributing end encompasses the ends of the waveguide and the ends of the host medium, and it should be understood that the waveguide and the host medium form a common region at the light-distributing end.

[0020] The waveguide may, though not required, be tapered from the receiving end to the light-distributing end so that the cross-section at the receiving end is larger than the cross-section at the light-distributing end. Alternatively, the sides of the waveguide may be parallel.

[0021] Since the waveguide is a multimode waveguide, it can propagate light through it in a wavelength-dependent manner. In other words, in a multimode waveguide, modes with different wavelengths propagate with different beating lengths. For example, lower-order modes can propagate within the waveguide, while higher-order modes can penetrate the sidewalls of the waveguide into the host medium and propagate within the host medium. In this way, an optical pattern is formed at the distribution edge. The distribution of the optical pattern across the host medium and the region within the waveguide at the distribution edge depends on the wavelength content of the light.

[0022] By way of example only, incident light of a plurality of wavelengths can propagate through the waveguide and the host medium, such that different wavelengths are provided with different intensity spatial distributions based on different modes excited in the waveguide. According to the present arrangement, different wavelengths can reach different positions of a light distribution end and form a light pattern at the light distribution end. However, it should be understood that the waveguide and the host medium do not necessarily have to completely separate different wavelengths into different portions of the light pattern. Rather, the waveguide and the host medium can provide a light pattern at a cross-section of the waveguide and the host medium, such as the light distribution end, wherein the spatial distribution of light is different for different wavelengths. However, it is contemplated that incident light of several wavelengths may alternatively be completely separated based on different modes excited in the waveguide, such that different wavelengths can reach different positions of the light distribution end.

[0023] By way of non-limiting example, the waveguide can be made of Si₃N₄ having a refractive index that varies from 2.0 to 2.1 over the visible spectrum of light, and the dielectric host medium can be made of SiO₂ having a refractive index that varies from 1.454 to 1.47 over the visible spectrum. By way of further non-limiting example, materials such as TiOₓ, NbOₓ, amorphous Si, or carbon-rich amorphous silicon can be used for the waveguide. It should be noted that the host medium can alternatively be a gas such as air. Furthermore, it should be understood that the light condensing element can be made of the same material as the waveguide or can be made of a different material.

[0024] As used herein, the term "photosensitive element" refers to an element that responds to light incident on the element by generating an electrical signal in response to light intensity. A plurality of photosensitive elements may be arranged on a detector and configured to enable reading of an electrical signal representative of light for image acquisition. By way of non-limiting example, photosensitive elements may be found in photodiodes, photomultiplier tubes (PMTs), and pixels on image detectors such as charge-coupled devices (CCDs) and complementary metal-oxide semiconductors (CMOSs). By way of example, the plurality of photosensitive elements may be in the form of pixels on a CCD or CMOS detector, but may alternatively comprise any other plurality of types of photosensitive elements.

[0025] By way of example, the plurality of photosensitive elements may be arranged in the plane of the detector. As a further example, the plane may be a flat surface of the detector.

[0026] According to one embodiment, the plurality of photosensitive elements are arranged in rows and columns forming an array of photosensitive elements. Accordingly, the plurality of photosensitive elements may be arranged regularly. This may facilitate the manufacture of the detector.

[0027] Typically, the photosensitive element has a square shape, but it is contemplated that the photosensitive element may alternatively have another shape such as a rectangle, a circle, or an ellipse.

[0028] However, it should be understood that the plurality of photosensitive elements do not need to be arranged regularly, and different photosensitive elements may have different sizes and / or shapes.

[0029] It should be understood that the waveguide and the host medium can, but are not limited to, separate the wavelength band of incident light onto the light pattern at the light distribution end, whereby different photosensitive elements can detect different wavelength bands or colors of the incident light. By way of non-limiting example, the wavelength bands may be separated in a Bayer-like pattern across the plurality of photosensitive elements.

[0030] One or more photosensitive elements may be associated with a specific wavelength band. As a non-limiting example, if the wavelength bands correspond to red, green, and blue light, the photosensitive elements are associated with the red, green, and blue wavelength bands, respectively. Furthermore, a combination of red and green may be used to represent yellow, and a combination of green and blue may be used to represent cyan.

[0031] An advantage of this embodiment is that a device for wavelength-dependent detection of light can be provided without using conventional color filters. When color filters are used, only a specific wavelength band is transmitted, so a relatively large portion of the focused light may be discarded, while unwanted wavelength bands can be removed by absorption or reflection by the color filter. According to the concept of the present invention, light is not filtered out of the optical path but rather redistributed and / or split into different paths based on wavelength, so that most, or preferably all, of the focused light can reach the detector. Therefore, this arrangement can provide wavelength-dependent light detection with higher efficiency and sensitivity.

[0032] Another advantage of this embodiment is that wavelength-dependent detection of light can be provided with little, or preferably no, dependence on the polarization of the light. Conventional techniques for wavelength-dependent detection may suffer from undesirable polarization dependence that affects the accuracy of detection. Therefore, this configuration can provide wavelength-dependent detection of light with higher accuracy in detection across different wavelength bands.

[0033] According to one embodiment, the photosensitive element is arranged planarly within the detection surface. The device further comprises an axis of symmetry that passes through the center of the detection surface and extends in a direction perpendicular to the detection surface, The light-gathering element and the waveguide are arranged symmetrically along the axis of symmetry, and the light-gathering element, waveguide, and multiple photosensitive elements extend symmetrically from the axis of symmetry in two orthogonal directions parallel to the detection surface.

[0034] In this configuration, the axis of symmetry can extend along the principal direction of light propagation. In this respect, the axis of symmetry can also be considered as the optical axis of the device.

[0035] For example, the two orthogonal directions could be the two directions in which the rows and columns of the detector's photosensitive elements are arranged.

[0036] This symmetrical arrangement can provide a symmetrical optical pattern with respect to wavelength, i.e., a symmetrical distribution of light at the beam edge. For example, shorter wavelengths may be closer to the axis of symmetry than longer wavelengths. As a further example, blue light may be located at or near the center of the optical pattern at the beam edge, while green and red light may be located further from the center of the optical pattern, distributed symmetrically in two orthogonal directions.

[0037] The advantage of this embodiment is that it is a simple method that provides wavelength-dependent detection of light, which is independent of the polarization of the light. The wavelength content or color of the light can be easily determined from such a regular and systematic distribution.

[0038] According to one embodiment, the waveguide and the host medium are configured to excite modes having a field distribution that is symmetric with respect to the symmetry axis of the waveguide.

[0039] As a non-limiting example, the waveguide and host medium may be configured to excite the mode (0,0) representing blue, the mode (2,0) and / or (0,2) representing green, and the mode (2,2) representing red.

[0040] According to one embodiment, the waveguide and the host medium are configured to propagate light such that a portion of the light propagates from the waveguide into the host medium in order to form a portion of the light pattern at the light distribution end.

[0041] The advantage of this embodiment is that strong separation between different wavelength bands can be provided, thereby reducing crosstalk between wavelength bands and improving the signal-to-noise ratio.

[0042] According to one embodiment, the waveguide and host medium are further configured to propagate light such that the distribution of the light pattern across the host medium and the region within the waveguide at the light distribution end is independent of the polarization of the light.

[0043] An advantage of this embodiment is that it can provide wavelength-dependent detection of light that is independent of the polarization of the light. Conventional techniques for wavelength-dependent imaging may suffer from undesirable polarization dependence that affects the accuracy of detection. Therefore, this arrangement can provide wavelength-dependent detection of light with higher accuracy in detection across different wavelength bands.

[0044] According to one embodiment, the light-gathering element is configured to generate a photonic nanojet for focusing light.

[0045] In this specification, the term "photonic nanojet" refers to a narrow, intense electromagnetic beam. For example, a nanojet can be generated by a dielectric microelement having a circular cross-section, such as a microsphere or microcylinder, which focuses light in its vicinity to form a beam that exits the element from the opposite side. Thus, if the optical focusing element has a focusing end with a circular cross-section, light in the vicinity of the focusing end can be focused into a nanojet exiting the optical focusing element at the output end.

[0046] Typically, light focusing elements are configured so that the nanojet is positioned along the device's axis of symmetry. However, it should also be noted that, alternatively, the nanojet may be slightly offset from the device's axis of symmetry. As a non-limiting example, the nanojet may be offset by as much as 100 nm from the axis of symmetry. Such an offset can still provide the device with polarization-independent light splitting.

[0047] Furthermore, the optical focusing element may be configured to provide nanojet at the boundary between the optical focusing element and the waveguide. Alternatively, the optical focusing element may be configured to provide nanojet near the boundary between the optical focusing element and the waveguide, but either within the optical focusing element or within the waveguide.

[0048] The advantage of this embodiment is that the combination of a multimode waveguide and a nanojet exhibits specific advantages in terms of optical efficiency, optical resolution, and spatial resolution.

[0049] Another advantage is that the stack for wavelength division, such as the total thickness of the waveguide, will be reduced. Furthermore, the reduced waveguide thickness may lead to a reduced number of fabrication steps, which in turn may lead to a simplified fabrication process. Moreover, the fabrication process for optical focusing elements for nanojet may be less complex compared to the fabrication processes for other optical focusing components.

[0050] According to one embodiment, the optical focusing element and the waveguide are made of the same material.

[0051] An advantage of this embodiment is that the manufacturing process can be simplified. If the optical focusing element and the waveguide are made from the same material, they can be fabricated using the same process, either immediately after or even simultaneously with the other.

[0052] According to one embodiment, incident light is incident from a medium having a first refractive index n1, The optical focusing element and waveguide are made of a material having a second refractive index n2. The host medium is made of a material having a third refractive index n3. The second refractive index n2 is greater than the first refractive index n1 and the third refractive index n3, respectively.

[0053] According to one embodiment, the waveguide has a straight shape along the extension from the light-receiving end to the light-distributing end such that the cross-section of the light-receiving end and the cross-section of the light-distributing end are of equal size, or the waveguide has a tapered shape along the extension from the light-receiving end to the light-distributing end such that the cross-section of the light-receiving end is larger than the cross-section of the light-distributing end.

[0054] According to one embodiment, the optical focusing element comprises a focusing end configured to focus incident light and a transmitting end configured to transmit the focused light from the optical focusing element to a waveguide, wherein the cross-section of the light-receiving end of the waveguide is larger than the cross-section of the transmitting end of the optical focusing element.

[0055] According to one embodiment, the cross-sectional width of the light-receiving end and the cross-sectional width of the light-distributing end are each 1 μm or less.

[0056] According to one embodiment, the device further comprises a spacer element disposed between the light distribution end and a plurality of photosensitive elements.

[0057] For some types of detectors used to detect light from waveguides that separate light by wavelength, it should be understood that space may be required between the waveguide and the detector to improve detection efficiency. For example, this may be the case with Si-based detectors.

[0058] However, it should be noted that spacer elements are not always necessary, for example, when thin-film detectors are used. This may be the case, for instance, with perovskite detectors.

[0059] According to one embodiment, the spacer element is a slab waveguide.

[0060] The advantage of this embodiment is that it provides an easy method for manufacturing a spacer element. A flat layer of material for the spacer element can be simply provided on the detector, and then the remaining structures of the waveguide, host medium, and light focusing element can be provided on top of the spacer element.

[0061] According to one embodiment, an anti-reflective coating is provided at the light distribution end.

[0062] Anti-reflective coatings can reduce, or even eliminate, light reflections that return to the waveguide as light reaches the light distribution end. In other words, most, and possibly all, of the light can be transmitted from the light distribution end to each photosensitive element. Anti-reflective coatings can be impedance equalizer coatings. For example, an anti-reflective coating may have a thickness of about one-quarter of the nominal wavelength of the light.

[0063] The advantage of this configuration is that optical loss is further reduced, and therefore the efficiency and sensitivity of the device's photodetection are further improved.

[0064] According to one embodiment, the apparatus further comprises deep trench isolation (DTI) technology, in which each photosensitive element is confined by a trench that prevents light incident on the photosensitive element from propagating to adjacent photosensitive elements.

[0065] If light incident on multiple photosensitive elements can propagate over a considerable distance, such as greater than 500 nm, the light can diffuse across several adjacent photosensitive elements, causing crosstalk between them. When this occurs, the spatial separation of light provided by the waveguide and host medium is lost. To prevent crosstalk, confinement can be used around each photosensitive element. DTI effectively functions as out-of-plane silicon waveguides where light is trapped by total internal reflection.

[0066] The advantage of this embodiment is that crosstalk can be efficiently reduced and, in some cases, avoided. This leads to an improved signal-to-noise ratio in the photodetector, which in turn leads to improved accuracy in the measurement of wavelength content in the incident light.

[0067] According to one embodiment, the DTI is further positioned within a spacer element.

[0068] However, if the device does not have spacer elements, it is conceivable that additional DTIs may be placed on top of the detector.

[0069] According to an alternative embodiment, the DTI is further positioned between the spacer element and the multiple photosensitive elements.

[0070] An advantage of this embodiment is that crosstalk can be further reduced, and therefore, the photodetection performance can be improved.

[0071] According to a second embodiment, an imaging system for wavelength-dependent imaging is provided, the imaging system comprising an array of the apparatus described in any one of the preceding claims.

[0072] The array of devices may be arranged in rows and columns, with different devices configured to detect light at different points in space. This arrangement may provide wavelength-dependent imaging. As described above, each device may represent a pixel (picture element), thereby corresponding to a spatial position in the scene from which each device is imaged, where each pixel contains information related to the wavelength content of light from the corresponding spatial position.

[0073] It should be understood that an imaging system may have a large imaging detector with enough photosensitive elements to provide all the multiple photosensitive elements for all the devices in such an array. Therefore, the multiple photosensitive elements of a particular device do not necessarily need to be physically separated from the multiple photosensitive elements of adjacent devices, but instead may form part of a larger imaging detector.

[0074] An advantage of this embodiment is that an imaging system for wavelength-dependent imaging can be provided without using conventional color filters. According to the concept of the present invention, light is not filtered out of the optical path, but rather redistributed and / or split into different paths based on the wavelength for each pixel, so that most, or preferably all, of the focused light can reach the imaging detector. Therefore, this arrangement can provide wavelength-dependent imaging with higher efficiency and sensitivity.

[0075] Another advantage of this embodiment is that wavelength-dependent imaging can be provided with little, or preferably no, dependence on the polarization of light. Conventional techniques for wavelength-dependent imaging may suffer from undesirable polarization dependence that affects the accuracy of light detection. Therefore, this configuration can provide wavelength-dependent imaging with higher accuracy in detection across different wavelength bands.

[0076] According to one embodiment, at least some of the photosensitive elements among a plurality of photosensitive elements in each device are shared between different devices, so that at least some of the photosensitive elements are arranged to receive light from the light distribution ends of at least two adjacent devices.

[0077] This arrangement allows photosensitive elements of the same size to be used for different wavelength bands. Due to the symmetry of the devices, and consequently the symmetry of the light patterns at the light distribution edges, adjacent devices may have the same wavelength or wavelength band at the sides or corners of the devices facing each other. In other words, a side of a device from which a certain wavelength band is distributed may face a side of an adjacent device from which the same wavelength band is distributed in the adjacent device. Thus, the sides and corners of the devices facing each other will each provide a matching wavelength band.

[0078] This symmetry allows the shared photosensitive element to receive light of the same wavelength band from different devices that share the same photosensitive element, thus enabling these devices to share the photosensitive element. This arrangement allows the photosensitive element to be shared between different devices without mixing different wavelength bands on the shared photosensitive element.

[0079] An advantage of this embodiment is that photosensitive elements can be shared between adjacent devices without wavelength band mixing occurring on the shared photosensitive elements, so these devices can be placed in close proximity to each other without any gaps between them. This, in turn, makes it possible to utilize all the photosensitive elements of the detector without leaving any photosensitive elements between adjacent devices unused. Therefore, this arrangement can provide an imaging system for wavelength-dependent imaging with high spatial resolution.

[0080] According to a third aspect, a method for wavelength-dependent detection of light is provided, and this method is The process involves using a light-gathering element to focus the incident light at the light-gathering edge of the light-gathering element, The process involves concentrating light at the output end of the light-gathering element, A waveguide placed within a host medium receives light from a light-gathering element at the light-receiving end, where the waveguide is a multimode waveguide, forming an extension from the light-receiving end to the light-distributing end, surrounded along the extension by the host medium, and the output end of the light-gathering element is directly coupled to the light-receiving end of the waveguide. The waveguide and host medium propagate light to form an optical pattern at the light distribution end, and the distribution of the optical pattern across the host medium and waveguide region at the light distribution end depends on the wavelength of the light. For wavelength-dependent detection of light, different photosensitive elements among multiple photosensitive elements receive different portions of the light pattern at the light distribution edge, It is equipped with.

[0081] The effects and features of the second and third embodiments are largely similar to those described above in relation to the first embodiment. Embodiments mentioned in relation to the first embodiment largely adapt to the second and third embodiments. It should be further noted that the concept of the present invention relates to all possible combinations of features unless otherwise specified.

[0082] Other objects, features, and advantages of the concept of the present invention will become apparent from the following detailed disclosure, the appended claims, and the drawings.

[0083] The above-mentioned and additional objectives, features, and advantages of the concept of the present invention will be better understood through the following illustrative and non-limiting detailed description with reference to the accompanying drawings. In the drawings, unless otherwise specified, similar reference numerals will be used for similar elements. [Brief explanation of the drawing]

[0084] [Figure 1A] Figure 1A illustrates a two-dimensional projection diagram of an integrated device for wavelength-dependent detection of light. [Figure 1B] Figure 1B illustrates a three-dimensional perspective view of a device for detecting the wavelength dependence of light. [Figure 1C] Figure 1C schematically illustrates a top view of the detection surface of a detector having multiple photosensitive elements. [Figure 1D] Figure 1D shows a series of examples of light transmission at the light distribution edge and the light intensity distribution detected by the array of photosensitive elements for incident light with a known wavelength content. [Figure 2] Figure 2 illustrates the detected light intensity in different photosensitive elements representing blue, green, and red light for four different linearly polarized incident light. [Figure 3A] Figure 3A schematically illustrates an integrated device for wavelength-dependent detection of light, further comprising a spacer element and an anti-reflective coating. [Figure 3B] Figure 3B schematically illustrates an integrated system with optional deep trench isolation (DTI) technology. [Figure 4A] Figure 4A schematically illustrates an imaging system for wavelength-dependent imaging. [Figure 4B] Figure 4B schematically illustrates a top view of the detection surface of the detector in the imaging system. [Figure 5] Figure 5 illustrates a schematic block diagram that concisely summarizes a method for detecting wavelength dependence of light. [Modes for carrying out the invention]

[0085] The technical content and detailed description of the present invention are described below in accordance with preferred embodiments, in conjunction with the attached drawings, but are not intended to limit the scope of the claims. The concept of the present invention can be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided for thoroughness and completeness and fully convey the scope of the concept of the present invention to those skilled in the art.

[0086] Figures 1A and 1B schematically illustrate an integrated device 100 for wavelength-dependent detection of light. Figure 1A illustrates a two-dimensional projection view of the device 100, and Figure 1B illustrates a three-dimensional perspective view of the same device 100.

[0087] The device 100 includes a light-gathering element 121 having a focusing end 122 and an output end 123 on the opposite side. The light-gathering element 121 is configured to focus light incident at the focusing end 122. The light may come from an object or scene focused by a lens (not shown here) on the flat surface of the focusing end 122, although other arrangements for guiding the light onto the focusing end 122 are also possible. The incident light may come from a medium having a first refractive index n1. For example, this medium may be ambient air.

[0088] The light focusing element 121 is further configured to propagate light from the focusing end 122 to the output end 123 so that the light is focused at the output end 123. In this example, the focusing of light is provided by the light focusing element 121, which is configured to generate a photonic nanojet. Light near the focusing end 122 can be focused into a nanojet beam exiting the light focusing element 121 at the output end 123.

[0089] As illustrated in Figures 1A and 1B, the light-gathering element 121 has a linear shape such that the cross-section of the light-gathering end 122 and the cross-section of the light-discharging end 123 are of equal width. However, as an alternative, the light-gathering element 121 may have a tapered or widening shape such that the cross-section of the light-gathering end 122 and the cross-section of the light-discharging end 123 are of different widths.

[0090] The apparatus 100 further comprises a waveguide 125 disposed within a host medium 128. The waveguide 125 forms an extension from a light-receiving end 126 to an opposite light-distributing end 127. Typically, the light-receiving end 126 and the light-distributing end 127 each form a flat surface. Along the extension, the waveguide 125 is surrounded by the host medium 128. However, at the light-receiving end 126 and the light-distributing end 127, the waveguide is not surrounded by the host medium 128. Instead, the waveguide 125 is positioned such that the light-receiving end 126 faces the output end 123 of the light-gathering element 121. The waveguide 125 may be positioned such that the light-receiving end 126 is directly coupled to the output end 123 of the light-gathering element 121. Alternatively, the waveguide 125 may be arranged such that a gap is formed between the light-receiving end 126 and the transmitting end 123.

[0091] Alternatively, it should be noted that the light-gathering element 121 may be surrounded by a host medium that also surrounds the transmitting end 123. In such a case, the host medium of the light-gathering element 121 may also cover the receiving end 126 of the waveguide 125. For example, the host medium of the light-gathering element may be the same host medium 128 as the waveguide 125, or it may be a different host medium with a different refractive index.

[0092] As illustrated in Figures 1A and 1B, the waveguide 125 has a tapered shape along the extension from the light-receiving end 126 to the light-distributing end 127 such that the cross-section of the light-receiving end 126 is larger than the cross-section of the light-distributing end 127. However, alternatively, the waveguide 125 may have a straight shape along the extension from the light-receiving end 126 to the light-distributing end 127 such that the cross-sections of the light-receiving end 126 and the cross-sections of the light-distributing end 127 are of equal size.

[0093] The waveguide 125 may be fabricated from a material having a second refractive index n2. The host medium 128 may be fabricated from a material having a third refractive index n3. For example, the refractive indices may be selected such that the second refractive index n2 is greater than the first refractive index n1 and the third refractive index n3, respectively. In this example, the optical focusing element 121 and the waveguide 125 are fabricated from the same material. Therefore, in this example, the optical focusing element 121 is also fabricated from a material having a second refractive index n2. However, the optical focusing element 121 and the waveguide 125 may, as an alternative, be fabricated from different materials having different refractive indices.

[0094] Waveguide 125 is configured to receive light from the output end 123 of the optical focusing element 121 at its receiving end 126. Most, or preferably all, of the light focused at the focusing end 122 of the optical focusing element 121 can be coupled into waveguide 125 via the receiving end 126. In order to couple all the light in the optical focusing element 121 into waveguide 125, the cross-section of the receiving end 126 of waveguide 125 is typically larger than the cross-section of the output end 123 of the optical focusing element 121.

[0095] Optionally, one or more additional layers may be provided between the transmitting end 123 and the receiving end 126. One or more additional layers may enhance the coupling of light between the light concentrating element 121 and the waveguide 125.

[0096] The waveguide 125 and host medium 128 are configured to propagate light from the light-receiving end 126 to the light-distributing end 127. Since the waveguide 125 is a multimode waveguide, the propagation of light through the waveguide 125 depends on the wavelength of the light. Therefore, light with different wavelengths can take different directions so as to form an optical pattern at the light-distributing end 127.

[0097] The waveguide 125 and the host medium 128 are configured to propagate light such that a portion of the light propagates from the waveguide 125 into the host medium 128 in order to form a portion of the light pattern at the light distribution end 127. As illustrated in Figure 1A, the shortest wavelength λ sLight having the intermediate wavelength λ can propagate along or near the axis of symmetry A, thereby emitting at or near the center of the light distribution end 127. m The light can be guided by the waveguide by internal reflection at the boundary between the waveguide 125 and the host medium 128, and may remain within the waveguide 125 until it exits the waveguide 125 at the light distribution end 127. Longest wavelength λ l The light can pass through the sidewall of the waveguide 125 at the boundary between the waveguide 125 and the host medium 128, and continue to propagate through the host medium 128 until it exits the host medium 128 at the light distribution end 127.

[0098] As a result, the distribution of the light pattern across the host medium 128 and the waveguide 125 at the light distribution end 127 depends on the wavelength of the light.

[0099] A detector 110 is positioned at the light distribution end 127 to detect the intensity of light at different wavelengths or different wavelength bands. The detector 110 comprises a plurality of photosensitive elements 114 arranged planarly within the detection surface. The detection surface is typically positioned parallel to the plane of the light distribution end 127. The axis of symmetry A extends through the center of the detection surface in a direction perpendicular to the detection surface. Furthermore, the light concentrating element 121 and the waveguide 125 are positioned symmetrically along the axis of symmetry A such that the light concentrating element 121, the waveguide 125, and the plurality of photosensitive elements 114 extend symmetrically from the axis of symmetry A in two orthogonal directions parallel to the detection surface.

[0100] Figure 1C schematically illustrates a top view of the detection surface of a detector 110 having multiple photosensitive elements 114. In this example, the multiple photosensitive elements 114 are arranged in rows and columns that form an array of photosensitive elements 114. The dashed lines correspond to the planar projection onto the detection surface of the combined width of the waveguide 125 and the host medium 128. Note that the width of this unit, as represented by the dashed lines, can be wider than the light-receiving end 126 of the waveguide, as it may be filled by the host medium 128. This is illustrated, for example, in Figures 1A and 1B.

[0101] The two orthogonal directions in which the detector 110, waveguide 125, and light-gathering element 121 are symmetrically positioned around axis A are the two directions in which the rows and columns of the photosensitive elements 114 of the detector 110 are positioned. These two directions are here denoted by x and y, respectively.

[0102] Multiple photosensitive elements 114 are arranged relative to the waveguide 125 and host medium 128 such that different photosensitive elements 114 receive different portions of the light pattern at the light distribution end 127. Different wavelength bands are exemplified by brighter or darker shading relative to each other, depending on the light wavelength within each wavelength band. Brighter shading represents shorter wavelengths, and darker shading represents longer wavelengths.

[0103] As illustrated in Figure 1C, the shortest wavelength of light is incident on the central photosensitive element 114a of this arrangement, and therefore near the axis of symmetry A. Further away from the axis of symmetry A, the intermediate wavelength is incident on the photosensitive element 114b at or near the edges of the waveguide / host medium 125, 128 arrangement. Further away from the axis of symmetry A, the longest wavelength of light is incident on the photosensitive element 114c at the corners of the waveguide / host medium 125, 128 arrangement.

[0104] For example, the wavelength band with the shortest wavelength may correspond to blue, the wavelength band with the intermediate wavelength may correspond to green, and the wavelength band with the longest wavelength may correspond to red. However, it should be understood that wavelength bands can alternatively represent different wavelengths or colors, and may further include wavelengths outside the visible portion of the spectrum, such as ultraviolet or infrared light.

[0105] This configuration may provide wavelength-dependent detection of light. The symmetry of this configuration also provides symmetry in terms of how different wavelength bands are distributed around the symmetry axis A.

[0106] Figure 1D illustrates an example of a pair of light transmission at the light distribution edge and the light intensity distribution detected by the array of photosensitive elements 114 for incident light with a known wavelength content. Only portions of the photosensitive elements 114 located beneath the waveguide and host medium are shown. Therefore, the corner and side photosensitive elements are cut off, and only the central photosensitive elements are fully shown. The gray level represents the power distribution.

[0107] The left-hand diagram in Figure 1D shows a characteristic light pattern resulting from purely blue incident light, where the wavelength is 450 nm. As also mentioned in Figure 1C, most of the light of this wavelength is incident on the photosensitive element 114a in the center of the waveguide / host medium arrangement.

[0108] The central figure in Figure 1D shows a characteristic light pattern resulting from purely green incident light, with a wavelength of 550 nm in this example. As also mentioned in Figure 1C, most of the light of this wavelength is incident on the photosensitive element 114b at the edges of the waveguide / host medium arrangement.

[0109] The right-hand side of Figure 1D shows a characteristic light pattern resulting from purely red incident light, where the wavelength is 650 nm. As also mentioned in Figure 1C, most of the light of this wavelength is incident on the photosensitive element 114c at the corners of the waveguide / host medium arrangement.

[0110] Therefore, the symmetry of the arrangement also provides symmetry in terms of how different wavelength bands are distributed around the symmetry axis A. In other words, the waveguide and host medium are configured to excite modes that have field distributions symmetric with respect to the waveguide's symmetry axis.

[0111] In this example, Si3N4 was used as the material having a refractive index n2 that varies from 2.0 to 2.1 across the visible spectrum. SiO2 was used as the dielectric host medium having a refractive index n3 that varies from 1.454 to 1.47 across the visible spectrum. Furthermore, in this example, the refractive index n1 = 1.

[0112] This example demonstrates that, due to the symmetry of the light pattern, a symmetrical Bayer pattern on a photosensitive element can be used for detection.

[0113] Figure 2 illustrates the light intensity detected by different photosensitive elements representing blue light, green light, and red light for four different linearly polarized incident light.

[0114] A typical problem with prior art is that light detected in different wavelength bands can depend not only on wavelength but also on the polarization of the light. This introduces errors in light measurement.

[0115] However, according to this configuration, the waveguide and host medium are further configured to propagate light in order to form an optical pattern at the optical end, such that the distribution of the optical pattern across the region within the host medium and waveguide at the optical end is independent of the polarization of the light.

[0116] Figure 2 illustrates the transmittance (T) of the entire visible spectrum under normal plane wave incidence, measured under the light distribution edge of the apparatus 100, for four different polarization angles: (i) 0°, (ii) 15°, (iii) 45°, and (iv) 90°. It can be seen that the light transmittance detected at different wavelengths for the three groups of photosensitive elements is substantially the same for all four polarization directions. Therefore, the response of the apparatus is actually polarization-independent. This polarization independence is due to the symmetry of the apparatus and the position of each photosensitive element in the detector, as explained in relation to the figure above.

[0117] It should be noted that although the transmittance results illustrated in Fig. 2 relate to apparatus 100, transmittance measurements for any apparatus disclosed herein will show equivalent results.

[0118] Fig. 3A schematically illustrates an integrated apparatus 200 for wavelength-dependent detection of light. Apparatus 200 shares several features with apparatus 100 described with reference to Figs. 1A to 1D, and detailed description thereof will not be repeated here.

[0119] Apparatus 200 includes a light condensing element 221 having a light condensing end 222 and an opposite output end 223. As illustrated in Fig. 3A, the light condensing element 221 has a diverging shape such that the cross-section of the output end 223 is larger than that of the light condensing end 222. In this example, the cross-section of the light condensing end 222 has a width W col = 220 nm, and the cross-section of the output end 223 has a width W tr = 340 nm. In this example, the height of the light condensing element 221 is H ce = 620 nm. Using a light condensing element 221 having a diverging shape, instead of a light condensing element having a linear shape and parallel side surfaces, provides an additional degree of freedom in controlling the concentration of light such as a nanojet beam. By way of example, the present arrangement may provide more efficient light concentration for oblique light incidence. In this way, the response of the apparatus may be less dependent on the incident angle of light.

[0120] Apparatus 200 further includes a waveguide 225 disposed within a host medium 228. The waveguide 225 forms an extension from a light receiving end 226 to an opposite light distribution end 227. The waveguide 225 has a tapered shape such that the cross-section of the waveguide 225 at the light receiving end 226 is larger than the cross-section of the waveguide 225 at the light distribution end 227. In this example, the cross-section of the waveguide 225 at the light receiving end 226 has a width W rec = 700 nm, and the cross-section of the waveguide 225 at the light distribution end 227 has a width W dis = 420 nm. In this example, the height of the waveguide 225 is H wg= 1.7 μm. Using a waveguide 225 with a tapered shape instead of a waveguide with a straight shape and parallel sides provides additional flexibility for controlling the beat length of the excitation mode. For example, by changing the angle of the tapered sides, the height to which light can pass through the sidewalls of waveguide 225 can be controlled. In this way, the light pattern can be controlled and crosstalk can be reduced.

[0121] Waveguide 225 can be fabricated from a material having a second refractive index n2. In this example, the optical focusing element 221 and waveguide 225 are fabricated from the same material and therefore have a second refractive index n2. However, alternatively, the optical focusing element 221 and waveguide 225 may be fabricated from different materials having different refractive indices. Furthermore, host medium 228 can be fabricated from a material having a third refractive index n3.

[0122] The apparatus 200 further comprises a spacer element 231 positioned between the light distribution end 227 and the plurality of photosensitive elements 214 of the detector 210. The purpose of the spacer element 231 is to provide an appropriate distance between the light distribution end 227 and the photosensitive elements 214. The spacer element 231 may be provided at a height that improves detection efficiency. For example, this may be required for a Si-based detector. In this example, the spacer element is H se It may have a height of 450 nm. The total width of the arrangement of the waveguide 225 and host medium 228 may be d = 0.8 μm. The width of each photosensitive element 214 may be 400 nm. As a non-limiting example, the spacer element 231 may be made of a material having a refractive index n5. The refractive index n5 may be different from any of the other refractive indices mentioned in the apparatus 200, or alternatively, it may be equal to one of the other refractive indices mentioned in the apparatus 200.

[0123] As illustrated in Figure 3A, the spacer element 231 is essentially a slab waveguide. However, in contrast to the conventional use of slab waveguides where light propagates inside the slab waveguide along the extension of the slab, in this configuration, light propagates across the extension of the slab waveguide. That is, light from the light distribution end 227 travels across the slab waveguide to reach the photosensitive element 214 of the detector 210.

[0124] The light distribution end 227 is further provided with an anti-reflective coating 240. The purpose of the anti-reflective coating is to reduce or eliminate light reflection returning into the waveguide 225 and / or host medium 228. With this arrangement, most, and possibly all, of the light can be transmitted from the light distribution end 227 across the spacer element 231 to each photosensitive element 214. This arrangement further improves the efficiency and sensitivity of the light detection of the device 200.

[0125] It should be noted that all dimensions mentioned with respect to apparatus 200 are merely examples and do not in any way limit the invention. Furthermore, it should be noted that any dimensions mentioned with respect to apparatus 200 may also be applicable to apparatus 100.

[0126] Figure 3B schematically illustrates an integrated system 200 with optional deep trench isolation (DTI) technology.

[0127] At the normal incidence of light, i.e., an incidence angle perpendicular to the surface of the focusing edge 222, the transmittance of light reaching the photosensitive element 214 of the detector 210 through this arrangement is high. However, in some arrangements, increasing the incidence angle of light can cause a reduction in the power transmitted through the waveguide arrangement. Furthermore, crosstalk of different wavelength bands reaching different photosensitive elements 214 may increase.

[0128] Several different measures can be taken to suppress crosstalk. For example, crosstalk can be suppressed by placing a color filter above the photosensitive element 214, reducing the size of the photosensitive element 214, or providing an absorption layer above the photosensitive element 214.

[0129] Another alternative to suppress crosstalk is to provide a deep trench isolation (DTI) 233 structure in the detector 210. By providing the DTI 233 technique in the apparatus 200, each photosensitive element 214 is confined by a trench that prevents light incident on one photosensitive element 214 from propagating to adjacent photosensitive elements 214. As illustrated in Figure 3B, the DTI 233 may optionally be located within a spacer element 231. By providing a deep trench 233 filled with a material having a lower refractive index compared to the material of the spacer element 231, reduced crosstalk, and therefore lower interference, between adjacent photosensitive elements 214 can be achieved.

[0130] Figure 4A schematically illustrates an imaging system 1000 for wavelength-dependent imaging. The imaging system 1000 comprises an array of devices 1100 for wavelength-dependent detection of light. In this example, the devices 1100 are exemplified as being of the same type as the devices 100 described in relation to Figures 1A to 1D. However, it should be understood that the devices 1100 could be any type of device disclosed herein, such as the devices 200 described in relation to Figures 3A to 3B.

[0131] The array of devices 1100 can form a fully integrated imaging system 1000, as illustrated in Figure 4A. However, alternatively, the array of devices 1100 may be formed from individual devices 1100 arranged adjacent to one another.

[0132] The imaging system 1000 includes a detector 1110 comprising an array of photosensitive elements 1114 arranged in rows and columns within the flat surface of the detector 1110. Each photosensitive element 1114 is configured to generate an electrical signal in accordance with the intensity of light incident on the photosensitive element 1114.

[0133] As illustrated in Figure 4A, the imaging system 1000 includes a large image detector 1110 having enough photosensitive elements 1114 to provide all the photosensitive elements 1114 for all the devices 1100. Thus, the photosensitive elements 1114 of a particular device 1100 are not physically separated from the photosensitive elements 1114 of adjacent devices 1100, but instead form part of the larger image detector 1110.

[0134] An array of waveguides 1125 is arranged within a host medium 1128 above an array of photosensitive elements 1114. In this arrangement, the host medium can extend between the waveguides 1125 of the array without leaving any gaps in the host medium between adjacent devices 1100. An array of light-gathering elements 1121 is arranged at the light-receiving end 1126, as described above. For clarity, only three light-gathering elements 1121 and waveguides 1125 are illustrated, but it should be understood that in actual embodiments, the array of photosensitive elements 1114 is completely covered, or at least largely covered, by the waveguides 1125 and the array of host medium 1128.

[0135] As illustrated in Figure 4A, the array of light focusing elements 1121 and waveguides 1125 is arranged in rows and columns so that different devices 1100 can detect light at different points in space. Each device 1100 is configured, as described above, to propagate light so as to form a light pattern at the light distribution end 1127, depending on the wavelength of light from a specific point in space. This arrangement can provide wavelength-dependent imaging. As described above, each device may represent a pixel 1100, thereby corresponding to a spatial position in the scene from which each device is imaged, where each pixel contains information related to the wavelength content of light from the corresponding spatial position.

[0136] It should be noted that if the optional DTI is provided in the apparatus 1100, crosstalk between different photosensitive elements within each apparatus 1100 can be reduced, as described above. However, an additional benefit of DTI applied in the imaging system 1000 is that crosstalk between photosensitive elements in adjacent apparatuses 1100 can also be reduced. This leads to an improved signal-to-noise ratio in the photodetector, which in turn leads to improved accuracy in the measurement of wavelength content in the incident light. Ultimately, this leads to improved image quality of the imaging apparatus 1000.

[0137] Figure 4B schematically illustrates a top view of the detection surface of a detector 1110 having multiple photosensitive elements 1114. The dashed lines correspond to the planar projection of the total width of the waveguide 1125 and host medium 1128 combined for each of the three devices 1100, as also illustrated in Figure 4A. Thus, the two orthogonal directions in which the detector 1110, waveguide 1125, and light-gathering element 1121 are symmetrically arranged around axis A are the two directions in which the rows and columns of the photosensitive elements 1114 of the detector 1110 are arranged. These two directions are here denoted as x and y, respectively.

[0138] For each device 1100, multiple photosensitive elements 1114 are arranged relative to the waveguide 1125 and host medium 1128 such that different photosensitive elements 1114 receive different portions of the light pattern at the light distribution end 1127. Different wavelength bands are exemplified such that brighter shadows represent shorter wavelengths and darker shadows represent longer wavelengths.

[0139] For each device 1100, the shortest wavelength of light is incident on the photosensitive element 1114a in the center of the arrangement, the intermediate wavelength is incident on the photosensitive element 1114b at the edge, and the longest wavelength is incident on the photosensitive element 1114c at the corner of the arrangement of waveguides / host media 1125, 1128.

[0140] As illustrated in Figure 4B, some of the photosensitive elements 1114b, 1114c within each device 1100 are shared between different devices 1100. In other words, some of the photosensitive elements 1114b, 1114c are arranged to receive light from the light distribution ends 1127 of at least two adjacent devices 1100.

[0141] As explained in relation to the aforementioned figure, the wavelength bands detected by the photosensitive elements 1114a, 1114b, and 1114c can correspond to blue light, green light, and red light, respectively. Therefore, in this arrangement, each of the photosensitive elements 1114b that detect green light can be shared between two adjacent devices 1100. Due to the symmetry of the light pattern at the light distribution end, the sides of the devices 1100 facing each other will provide a matching wavelength band. Thus, the photosensitive elements 1114b can be shared between different devices 1100 without mixing different wavelength bands on the shared photosensitive elements 1114b. Furthermore, each of the photosensitive elements 1114c that detect red light can be shared between four adjacent devices 1100. In this case as well, due to the symmetry of the light pattern at the light distribution end, the corners facing each other will provide a matching wavelength band, and thus, the photosensitive elements 1114c can be shared between different devices 1100 without mixing different wavelength bands. In this configuration, the photosensitive element 1114a that detects blue light is not shared between different devices 1100, but is unique to each device 1100.

[0142] Since the photosensitive elements 1114b and 1114c can be shared between adjacent devices 1100 without any mixing of wavelength bands occurring on the shared photosensitive elements 1114b and 1114c, these devices 1100 can be arranged in a compact manner without any gaps between them. Thus, an imaging system 1000 for wavelength-dependent imaging with high spatial resolution can be provided.

[0143] It should be understood that the sharing of photosensitive elements 1114 between adjacent devices is presented here only as a non-limiting example. Alternatively, it is equally conceivable that none of the photosensitive elements 1114 are shared, and instead, they are unique to each respective device 1100.

[0144] Figure 5 illustrates a schematic block diagram that concisely summarizes the method for detecting wavelength dependence of light. While the steps of this method are listed in a specific order herein, it should be understood that they can be performed in any appropriate order.

[0145] The method may include using a light-gathering element to focus the incident light at the light-gathering end of the light-gathering element (S502).

[0146] The method may include concentrating light at the output end of the light-gathering element (S504).

[0147] The method may include receiving light from a light-gathering element at the light-receiving end (S506) via a waveguide placed in a host medium. The waveguide is a multimode waveguide and forms an extension from the light-receiving end to the light-distributing end, and is surrounded along the extension by a host medium. The output end of the light-gathering element is directly coupled to the light-receiving end of the waveguide.

[0148] The method may include propagating light through a waveguide and a host medium to form a light pattern at the light distribution end (S508). The distribution of the light pattern across the region in the host medium and waveguide at the light distribution end depends on the wavelength of the light.

[0149] The method includes receiving different portions of the light pattern at the light distribution end in different photosensitive elements among a plurality of photosensitive elements for wavelength-dependent detection of light (S510).

[0150] In the foregoing, the concept of the present invention has been described primarily by reference to a limited number of examples. However, as will be readily apparent to those skilled in the art, examples other than those disclosed above are equally possible within the scope of the concept of the present invention, as defined by the appended claims.

Claims

1. An integrated device (100, 200, 1100) for detecting the wavelength dependence of light, A light-gathering element (121, 221, 1121) having a light-gathering end (122, 222) and an output end (123, 223), wherein the light-gathering element (121, 221, 1121) is configured to gather incident light at the light-gathering end (122, 222) and concentrate the light at the output end (123, 223), Waveguides (125, 225, 1125) are arranged within a host medium (128, 228, 1128), where the waveguides (125, 225, 1125) are multimode waveguides, forming an extension from the light-receiving end (126, 226, 1126) to the light-distributing end (127, 227, 1127), and the extension is surrounded along the host medium (128, 228, 1128), and the output end (123, 223) of the light-gathering element (121, 221, 1121) is directly coupled to the light-receiving end (126, 226, 1126) of the waveguides (125, 225, 1125), and the waveguides (125, 225 The 1125) is configured to receive the light from the light-collecting elements (121, 221, 1121) at the light-receiving ends (126, 226, 1126), the waveguides (125, 225, 1125) and the host medium (128, 228, 1128) are configured to propagate the light in order to form a light pattern at the light-distributing ends (127, 227, 1127), and the distribution of the light pattern over the region within the host medium (128, 228, 1128) and the waveguides (125, 225, 1125) at the light-distributing ends (127, 227, 1127) depends on the wavelength of the light. A plurality of photosensitive elements (114, 214, 1114), wherein different photosensitive elements (114, 214, 1114) among the plurality of photosensitive elements are arranged at the light distribution ends (127, 227, 1127) to receive different portions of the light pattern for wavelength-dependent detection of light, A device equipped with (100, 200, 1100).

2. The plurality of photosensitive elements (114, 214, 1114) are arranged planarly within the detection surface. The apparatus (100, 200, 1100) further comprises an axis of symmetry that passes through the center of the detection surface and extends in a direction perpendicular to the detection surface, The apparatus (100, 200, 1100) according to claim 1, wherein the light-gathering elements (121, 221, 1121) and the waveguides (125, 225, 1125) are each arranged symmetrically along the axis of symmetry, and the light-gathering elements (121, 221, 1121), the waveguides (125, 225, 1125), and the plurality of photosensitive elements (114, 214, 1114) extend symmetrically from the axis of symmetry in two orthogonal directions parallel to the detection surface.

3. The apparatus (100, 200, 1100) according to claim 2, wherein the waveguides (125, 225, 1125) and the host medium (128, 228, 1128) are configured to excite modes having a field distribution symmetric with respect to the symmetry axis of the waveguides (125, 225, 1125).

4. The apparatus (100, 200, 1100) according to any one of claims 1 to 3, wherein the waveguides (125, 225, 1125) and the host medium (128, 228, 1128) are further configured to propagate light such that the distribution of the light pattern over the host medium (128, 228, 1128) and the region within the waveguides (125, 225, 1125) at the light distribution end (127, 227, 1127) is independent of the polarization of the light.

5. The apparatus (100, 200, 1100) according to any one of claims 1 to 4, wherein the light focusing elements (121, 221, 1121) are configured to generate a photonic nanojet for focusing the light.

6. The waveguide (125, 225, 1125) has a straight shape along the extension from the light-receiving end (126, 226, 1126) to the light-distributing end (127, 227, 1127) such that the cross-section of the light-receiving end (126, 226, 1126) and the cross-section of the light-distributing end (127, 227, 1127) are of equal size, or the waveguide (125, 225, The apparatus (100, 200, 1100) according to any one of claims 1 to 5, wherein the extension from the light-receiving end (126, 226, 1126) to the light-distributing end (127, 227, 1127) has a tapered shape, such that the cross-section of the light-receiving end (126, 226, 1126) is larger than the cross-section of the light-distributing end (127, 227, 1127).

7. The apparatus (100, 200, 1100) according to any one of claims 1 to 6, wherein the cross-sectional width of the light-receiving end (126, 226, 1126) and the cross-sectional width of the light-distributing end (127, 227, 1127) are each 1 μm or less.

8. The apparatus (200) according to any one of claims 1 to 7, further comprising a spacer element (231) disposed between the light distribution end (227) and the plurality of photosensitive elements (214).

9. The apparatus (200) according to claim 8, wherein the spacer element (231) is a slab waveguide.

10. The apparatus (200) according to any one of claims 1 to 9, wherein the light distribution end (227) is provided with an anti-reflective coating (240).

11. The apparatus (200) according to any one of claims 1 to 10, further comprising deep trench isolation (DTI) (233) technology, wherein each photosensitive element (214) is confined by a trench that prevents light incident on the photosensitive element (214) from propagating to adjacent photosensitive elements (214).

12. The apparatus (200) according to claim 11, as dependent on claim 8 or 9, wherein the DTI (233) is further disposed within the spacer element (231).

13. An imaging system (1000) for wavelength-dependent imaging, wherein the imaging system (1000) comprises an array of the apparatus (1100) described in any one of claims 1 to 12.

14. The imaging system (1000) according to claim 13, wherein at least some of the photosensitive elements (1114) in each device (1100) are shared between different devices (1100), so that at least some of the photosensitive elements (1114) are arranged to receive light from the light distribution ends (1127) of at least two adjacent devices (1100).

15. A method for detecting the wavelength dependence of light, wherein the method is The light concentrating element collects the light incident at the concentrating end of the light concentrating element (S502), The light is concentrated at the output end of the light-collecting element (S504), The waveguide arranged in the host medium receives the light from the light-collecting element at the light-receiving end (S506), wherein the waveguide is a multimode waveguide, forms an extension from the light-receiving end to the light-distributing end, is surrounded along the extension by the host medium, and the output end of the light-collecting element is directly coupled to the light-receiving end of the waveguide. The waveguide and the host medium propagate the light to form a light pattern at the light distribution end (S508), wherein the distribution of the light pattern over the region within the host medium and the waveguide at the light distribution end depends on the wavelength of the light. For wavelength-dependent detection of light, different photosensitive elements among a plurality of photosensitive elements receive different portions of the light pattern at the light distribution end (S510), A method for providing this.

Images