Interpretation of optical signals from array metasurfaces

Abstract

A system and method interprets optical characterization tests performed using a set of optical devices. Each device includes one or more arrays of optical metasurface structures, with the arrays tailored to have distinct characteristics that differentiate them from one another. First and second data are accessed, capturing a physical fingerprint of each device and the results of an optical characterization test performed using each device, respectively. The results of the test are affected by each distinct characteristic of the array. Each device is identified based on the accessed first data, which allows a readout key associated with the identified device to be obtained. The readout key addresses a respective one of the distinct characteristics. Finally, the second data is interpreted according to the obtained readout key to interpret the results of the optical characterization test. The present invention is also directed to a related computer program product.

Description

[Technical field]

[0001] The present disclosure relates generally to techniques for interpreting optical characterization tests performed using several optical devices, and in particular to a method based on a device with an array of optical metasurface structures, where the array is tailored to have distinctly different properties that serve as a set secret, and where a physical fingerprint of the device is additionally utilized to authenticate the device. Summary of the Invention

[0002] According to a first aspect, a method for testing a set of optical devices is provided. Each device includes one or more arrays of optical metasurface structures. The devices are adjusted such that their respective arrays have distinct characteristics. Thus, the optical devices are different from each other due to the distinct characteristics of the arrays. The method includes a series of steps performed for each device of the set. First, first and second data are accessed (for example by a server) capturing, respectively, the physical fingerprint of each device and the result of an optical characterization test performed using each device. Since the devices have distinct characteristics, the result of the test performed using the device is influenced by each distinct characteristic of the array. That is, the result of the characterization test performed using a given device of the set is influenced by each one of the distinct characteristics. Each device is identified based on the accessed first data, which allows obtaining a readout key associated with the identified device. This readout key addresses each one of the distinct characteristics. Finally, the second data is interpreted according to the obtained readout key in order to resolve the result of the optical characterization test. This result is then provided to the testing device.

[0003] Optical characterization testing performed using an optical device containing distinct arrays can result in the formation of distinct or merged optical signals (attributable to the distinct arrays), all of which therefore affect or in some way form part of the outcome of the test.

[0004] The method of the present application allows the realization of two levels of security. First, the physical fingerprint of each optical device is difficult, if not impossible, to clone so that each optical device is unambiguously identified. Second, the readout key can only be obtained for those devices that are duly identified. Also, the user of the device may possibly be authenticated during this process. Thus, only genuine devices (and possibly authenticated users) can, for example, have the server properly interpret the results or provide analytical information to interpret the data acquired using the tuned optical device.

[0005] In some embodiments, the outcome is influenced by both a respective one of the distinct characteristics of each device and the physical fingerprint. In this case, each readout key may be devised to address both a respective one of the distinct characteristics of each device and the physical fingerprint. Furthermore, accessing the first and second data may first include receiving characterization data. In that case, the first and second data are determined based on the received characterization data with the intention of identifying each device in order to obtain an associated readout key and to interpret the second data according to the obtained readout key. Relying on a single characterization step (where both types of data are obtained) may be advantageous in some applications, since it may simplify operations to be performed locally, for example at the point of care.

[0006] Preferably, the physical fingerprint is an unclonable characteristic of one or more arrays of each device. An unclonable characteristic, such as a physical unclonable characteristic, makes it more difficult (or even impractical) for a malicious user to clone an optical device of an array. Variations may rely on built-in security features instead of unclonable characteristics. Further variations may utilize unclonable characteristics of or security features embedded in physical anchors attached to the optical device.

[0007] In some embodiments, each of the optical devices of the set includes two or more arrays of metasurface structures that combine to give the optical devices distinct properties such that the devices of the set are different from one another. Thus, the properties can be more easily tailored to produce different (but predictable) properties and thereby different characterization results when performing optical characterization tests. Nevertheless, the optical devices can be assigned appropriate readout keys, such keys including codes, functions, etc., according to which the results of the tests can be correctly interpreted.

[0008] Preferably, the metasurface structures of at least one of the arrays of each device are coated with a substance for selectively binding the analyte, the substance forming the respective functionalization pattern of the array of devices. The result of the characterization test captured by the second data (for each device) is influenced by both the metasurface structures of the respective array (for each device) and the respective one of the functionalization patterns. The functionalization patterns can generate distinctly different optical signals, possibly all of which are part of the result (for each device). The readout key therefore also then addresses the respective one of the functionalization patterns.

[0009] Preferably, the material comprises a molecular receptor for selectively binding the analyte. The metasurface structures of at least one of the arrays of each device are coated with the molecular receptor such that the array of devices is functionalized according to a respective functionalization pattern formed by the molecular receptor.

[0010] For example, two or more of the arrays of each device may be coated with distinct types of molecular receptors to selectively bind distinct types of analytes. The receptors may be formed, for example, as molecular compounds immobilized on the surface of one or more metasurface structures. Each of the molecular compounds may include several moieties, including a first moiety immobilized on the surface and a second moiety that is a receptor chemically bound to the first immobilized moiety via a backbone. These several moieties may advantageously include a third moiety that is a protecting moiety for acetylene, the protecting moiety being bound to the backbone acetylene unit via an electrochemically cleavable bond. In that case, the method may further include deprotecting the backbone acetylene unit of the molecular compound by electrochemically cleaving the protecting moiety and then binding the molecular receptor to the deprotected acetylene unit. This deprotection mechanism results in an acetylene-functionalized surface, since the initially protected acetylene unit is immobilized on the surface. Thus, providing a chemically flexible attachment, which allows for subsequent binding of a variety of functional receptors to the cleaved compound. Together with electrochemically processable deprotection, site-selective functionalization can be performed to create metasurface devices with different materials (patterns).

[0011] In some embodiments, the results of the optical characterization include optical data representative of a spectral response of each device, for example, a spectral response of each array of each device. Preferably, the method further includes performing an optical characterization test for each device, prior to accessing the first data and the second data, by illuminating each array of each device with electromagnetic radiation at a frequency that matches a resonant frequency of the metasurface structures of the array in the absence of analyte. The spectral response may be, for example, a response to electromagnetic radiation transmitted through each device, where the spectral response reflects a change in absorption resonance caused by an effective change in the dielectric environment of the metasurface structures in one or more of the arrays of devices.

[0012] In some embodiments, the method is performed (at least in part) in a server in data communication with the set of client devices. In such a case, the method may further include, for each device, receiving data from one of the client devices paired with each optical device before accessing the first data and the second data, whereby the server can access the first data and the second data based on the received data, such that the server identifies each device based on the accessed first data and accordingly interprets the second data according to the obtained read key. In a variant, the interpretation is performed on the client side.

[0013] The method may further include, after identifying each device and interpreting the second data to resolve a result of the optical characterization test, sending a message to the one of the client devices including information regarding the resolved result. In a variant, the message may include information used to interpret the optical data, thereby enabling the result to be generated by the client device itself.

[0014] In some embodiments, the method further includes, for each device of the set, fabricating each device such that one or more arrays of each device have a respective one of the distinct characteristics prior to accessing the first data and the second data for any device of the set of devices, and associating a read key for the respective one of the distinct characteristics with an identifier of each device.

[0015] In some embodiments, the method further includes, after fabricating each device and before accessing the first data and the second data for any device of the set of devices, reading a physical fingerprint of each device to obtain a digital fingerprint corresponding to the physical fingerprint, and associating the digital fingerprint with an identifier of each device.

[0016] In some embodiments, each array of devices of each of the devices includes a pattern of repeating cells of metasurface structures, each cell including at least one (e.g., two) metasurface structures. The metasurface structures are preferably formed as semiconductor layer structures disposed on a substrate. The substrate may be transparent, for example, to allow optical characterization inspection in transmission. The semiconductor structures may optionally each have lateral dimensions between 1 nm and 500 nm on average, the lateral dimensions being measured parallel to the major surface of the substrate. Preferably, the semiconductor structures each have vertical dimensions between 10 nm and 500 nm on average, with a standard deviation of the vertical dimensions being less than 5 nm, the vertical dimensions being measured perpendicular to the major surface of the substrate.

[0017] According to another aspect, disclosed herein is a computer program product for interpreting optical characterization tests performed using a set of devices as described above, where each device includes one or more arrays of electromagnetic metasurface structures, and the devices are tuned such that each array has distinctly different characteristics. The computer program product includes a computer readable storage medium having program instructions embodied therewith, the program instructions being executable by a processing means to cause the processing means to implement steps according to the method of the present application for each device of the set. That is, such program instructions cause the first data and the second data to be accessed as described above, to identify each device based on the accessed first data, to obtain a read key, and to interpret the second data according to the read key to interpret the results of the optical characterization test.

[0018] Methods and computer program products will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which:

[0019] The accompanying drawings, in which like reference numbers refer to identical or functionally similar elements throughout the different views, and which, together with the following detailed description, are incorporated in and form a part of this specification, further illustrate various embodiments, and all serve to explain various principles and advantages according to the present disclosure. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a block diagram that illustrates, in some embodiments, the components of a system including an optical device having an array of functionalized metasurface structures, an optical detector, a smartphone connected to the detector, and a server connected to the smartphone for interpreting optical characterization tests performed using the optical device. In a variant, a mobile phone is used as the optical detector, and the smartphone's built-in camera is used. [Diagram 2]FIG. 2 is another block diagram that illustrates, in some embodiments, a server interacting with several optical devices (having distinct array characteristics) via respective connected smartphones to interpret optical characterization tests performed using the optical devices. [Diagram 3] 1A and 1B are schematic top views illustrating optical devices having distinct array characteristics (indicated by distinct fill patterns) according to some embodiments. [Figure 4] FIG. 13 is a sequence diagram illustrating how metasurface structures of an array of optical devices can be coated with molecular receptors to selectively bind analytes to form a given functionalization pattern of the array of optical devices, according to an embodiment. [Diagram 5] 1 is a flow chart showing the general steps of a method for interpreting an optical characterization test performed using a set of optical devices, where first and second data are obtained by respective characterization (or detection) steps. In some embodiments, each device is identified based on the first data to obtain an associated readout key, which is then used to interpret the second data. [Figure 6] 6 is a flowchart similar to that of FIG. 5, except that in some embodiments, a single characterization step is required to obtain the characterization data from which the first and second data are extracted. [Figure 7](A), (B), and (C) are diagrams showing wavelength bins (i.e., intervals, see Fig. 7(A)) used to measure the optical wavelength resonance obtained due to the array of metasurface structures. Intended to authenticate the optical device later, the signals obtained (e.g., by the manufacturer before or during the commissioning of the optical device) can be recorded and stored (Fig. 7(B)). Subsequently, the signals obtained by the end - user of the device are made capable of identifying the corresponding bins, thereby enabling the authentication of the optical device (Fig. 7(C)). Thus, in some embodiments, this enables the identification of the corresponding read - out key that is ultimately used to interpret the signal values. [Figure 8A] FIG. showing a cloud - computing environment according to an embodiment of the present invention. [Figure 8B] FIG. showing an abstraction model layer according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The accompanying drawings show schematic representations of devices or parts thereof, relating to some embodiments. The technical features illustrated in the drawings are not necessarily shown to the same scale. Unless otherwise indicated, like or functionally similar elements in the figures are assigned the same reference numerals.

[0022] Ensuring the authenticity of products is a necessity across multiple industries, especially when there is a risk of harmful or other negative consequences if a counterfeit or already used product is used. It is important to track and trace the logical and physical path, condition, and chain of custody (or ownership) of goods throughout the supply chain and asset lifecycle, but it is also desirable to maintain a tight link between the physical object and its digital representation. Blockchain (or any other digital track / trace solution) is in most cases insufficient to prove authenticity, correctness, or legitimacy, e.g., uninterrupted chain of custody, or a combination of these, in the supply chain or throughout the product lifecycle. In general, such attributes can only be verified if trust can be extended to the physical domain. Thus, physical objects need to be linked to associated digital records.

[0023] Typically, an object is associated with a digital record by a unique identifier (UID) that represents either an individual object or a class of object, such as by model, batch, place of manufacture, manufacturer, etc. The UID is typically printed, embossed, or attached as a tag to the object or its packaging. Most UIDs can be easily copied, for example, and attached to illegal clones of the object. Thus, an identifier alone cannot uniquely and securely identify (i.e., authenticate) an object.

[0024] To solve this problem, the concept of cryptographic anchors is introduced. A cryptographic anchor utilizes a set of characteristics of a physical object to securely associate the physical object with a UID. These characteristics include physical fingerprints (e.g., uncontrollable aspects such as manufacturing errors and differences in material composition), built-in security features (e.g., tunable inherent material properties and material functionalization), and configured secrets (e.g., based on cryptographic keys).

[0025] In addition to this, optical metasurface structures are an emerging class of planar optical elements that find applications in various fields due to their high sensitivity to changes in their local dielectric environment. Metasurface structures can be made of, for example, metal or dielectric materials. Such elements allow light to be manipulated in a highly efficient manner below the diffraction limit. Applications include electromagnetic field enhancement, polarization conversion, spatial light bending, spectroscopic filtering, and narrowband absorption. Metasurfaces tailored to operate in the visible and near-infrared regions of the electromagnetic spectrum typically have nanometer-sized dimensions ranging between tens and hundreds of nanometers or even smaller. The operation of such structures mainly depends on the resonance conditions with incident light of a specific wavelength.

[0026] For example, a shift in the absorption resonance can be measured. Such changes can be employed for compound-selective sensing, for example by functionalizing the metasurface with molecular receptor compounds that allow selective binding of the analyte, thereby enabling the required dielectric constant change. Due to the spectrally narrow characteristics, for example the absorption dip, the response of the device cannot be read out by laboratory instrumentation (for example using a spectrometer or a laser-based system), nor by a tabletop device using a single spectrally narrow light source in conjunction with, for example, a miniature CMO imager. For example, one may want to implement such a technique on an IoT device or a mobile phone, connected to a cloud application and thus made available by individuals for mobile or home use. However, situations involving distributed devices or mobile phones make tracking the authenticity of the product more difficult and therefore require additional security measures.

[0027] The following description is structured as follows: general embodiments and schematic variations are described first (Section 1), followed by a next section (Section 2) that provides technical implementation details for specific embodiments (Section 2.1), preferred methods of fabrication (Section 2.2), and computer program products (Section 2.3) and computerized devices (Section 2.4) used in some embodiments.

[0028] The present method and variations thereof are collectively referred to as the "present method." All "Sij" references refer to method steps in the flowcharts of Figures 5 and 6, while the reference numbers refer to devices, physical parts or components relevant to some embodiments.

[0029] 1. General embodiments and schematic variations 1, 2, 5 and 6, first an embodiment of a method for interpreting an optical characterization test performed using a set of optical devices 1, 1a-1c will be described.

[0030] Each device includes one or more arrays 21-26 of optical metasurface structures 12, also called electromagnetic metasurface structures in the literature. Such structures 12 may be referred to below as "metasurfaces". In the context of the present application, such metasurface structures can consist of a dielectric material, a semiconductor material such as silicon, or a metal. A semiconductor, for example silicon, is preferably used, and the metasurface structures are preferably fabricated using an indirect transfer process, such as the one described in section 2.2, resulting in accurate and neat metasurface structures. As is well known, such metasurface structures are arranged according to a given in-plane pattern. An optical device may include a single array of metasurface structures in an application. However, each optical device may include several arrays of metasurfaces, as in some embodiments described below with reference to Figures 2 to 4. As detailed in section 2.1, the optical devices 1, 1a-1c of the present application are preferably fabricated as sensing devices.

[0031] The optical devices of the set 1, 1a-1c are specially tailored so that their respective arrays 21-26 have distinctly different properties, and as will be described in more detail below, the properties of the different types of arrays can be exploited to differentiate the devices.

[0032] The present method includes a series of steps performed for each optical device of the set. In what follows, such steps are often described with reference to a given device 1. However, similar steps will be performed for each device of the set, typically independently and therefore asynchronously.

[0033] Firstly, first and second data need to be accessed S31, S31a (FIG. 5), for example by server 300 (FIG. 1). The first data captures the physical fingerprint of the given device 1, and the second data reflects the result of an optical characterization test S25 (FIG. 5) performed using the device 1, the result being influenced by certain characteristics of the array of the device 1. In the context of this application, optical characterization test refers to a test that involves the interaction of electromagnetic waves (not necessarily limited to the visible range) with electromagnetic matter.

[0034] The optical devices of the set have distinct arrays or sets of arrays that exhibit distinct characteristics as the devices are different. Also, each optical device may possibly include several arrays with distinct characteristics. That is, not only are the optical devices different from each other (due to the respective arrays), but in addition, the arrays of the same device may also be different. In that case, an optical characterization test performed using a given optical device may give rise to distinctly different optical signals (due to the distinct arrays), which may possibly be combined (if all arrays are illuminated simultaneously) or may be acquired one after the other (if the arrays are illuminated one at a time in succession). Thus, all such distinct signals affect or are somehow part of the result of this test. Such signals are captured by or somehow affect the second data of the test performed using each optical device of the set.

[0035] The first and second data are utilized for each device of the set as follows: First, referring to Figure 5, a given device 1 is identified S32 based on the accessed first data, and a read key S33 associated with the identified device is obtained. This assumes that the read key has been devised S15 to address specific characteristics of the given device 1. More generally, the read keys associated with the optical devices 1, 1a-1c address distinctly different characteristics of each of these optical devices, as will be explained in more detail below.

[0036] Finally, the accessed second data for said given device 1 can be interpreted S35 according to the obtained read-out key to reveal the results of the optical characterization tests performed using this device 1. More generally, the same steps are performed for each device of the set to reveal the results of the optical characterization tests performed using each device with its respective read-out key. These results may then be provided to an inspection device associated with the entity performing the tests. For example, the device may be a diagnostic computer associated with an inspector or the like, or it may be an automated device receiving control instructions from another source.

[0037] Some of the concepts introduced above are elaborated below. First of all, a physical fingerprint captures the inherent physical characteristics of a device, which are typically uncontrollable or non-deterministic characteristics of the device resulting from deviations or errors during the manufacturing process (e.g., physically unclonable characteristics). In the context of the present application, such physical fingerprints may result from, for example, manufacturing or composition errors. Here, the physical fingerprint of a particular optical device 1 is used to identify and / or authenticate this particular device 1. This may require, in some cases, performing an initial characterization of the device to read out the associated physical fingerprint before performing said optical characterization test, as envisaged in the flow chart of FIG. 5.

[0038] The results of the optical characterization tests are influenced by the deterministic properties of each array 21-26 of each device 1, as opposed to a physical fingerprint that typically captures non-deterministic properties of the device 1. Each optical device may, for example, include metasurface structures 12 with distinctly different types of molecular receptors (see Figs. 3 and 4) or other chemicals. Some metasurface structures may have receptors and others may not (as shown in Figs. 3 and 4). Also, some of the metasurface structure arrays may be coated with the same type of receptors, etc. (or may not have any receptors at all). Thus, the devices 1, 1a-1c may exhibit distinctly different functionalization patterns. For example, functionalization patterns may be obtained by, for example, randomly varying the type of functionalization across the array of each optical device.

[0039] The objective of the optical characterization tests performed is ultimately to detect a specific analyte. For example, the selective binding properties of the functionalized metasurface structures can be exploited to detect this analyte. However, the distinct characteristics of the array of the optical device (e.g., functionalization pattern) also serve as built-in security features. In variants of the functionalization pattern, other fully controllable characteristics of the array may be exploited to realize the required security features, such as the geometry of the metasurface, which gives rise to geometry-dependent optical properties and thus to a geometry-dependent optical signal. The geometry of the metasurface typically refers here to the in-plane shape and dimensions of the metasurface (e.g., ellipses as assumed in Figs. 2 and 3) and / or the distance between the two metasurface structures (of each pair), although the role of the in-pair distance typically plays a less important role than that of the in-plane shape and dimensions of the metasurface. In another embodiment, both receptor functionalization and geometric differences are exploited.

[0040] In all cases, since arrays of various optical devices have clearly different pre-set characteristics, such characteristics can serve as set secrets. Thus, since the devices are different and thereby have clearly different set secrets, the results of the optical property analysis inspection are "encrypted" (or made unreadable in some way) by this set secret. This is more advantageous than solutions that utilize only the differences in receptors and their geometries, as such differences may in some cases (e.g., using optical means, electron microscopes, chemical property analysis, or a trained eye) be detected or reverse-engineered.

[0041] As described above, two types of data are accessed and utilized. The first data is used, for example, to identify a particular device for the purpose of S32 identifying the device in order to obtain an identifier of the device and then S33 identifying the read key associated with that identifier, where the read key can also serve as an identifier. The obtained read key is then used to elucidate the results of the property analysis inspection. That is, the read key compensates for the specificity of each optical device to enable the correct interpretation of the second data. Such steps may be performed (at least in part) in a server 300 that communicates with client devices 200, 200a - 200c (e.g., smartphones) that themselves communicate with optical detectors 100, 100a - 100c (e.g., CMOS imaging devices, CCDs). The optical detectors are used to read the optical signals obtained by the optical property analysis inspection performed using optical devices 1, 1a - 1c as shown in FIGS. 1 and 2. Since the method of the present application requires interaction with client devices 200, 200a - 200c, some of the steps may be performed partially or in cooperation using a secure dedicated application executed, for example, on the client device. Further, some of these steps may be performed mainly on client devices 200, 200a - 200c.

[0042] Tests performed using different optical devices 1, 1a-1c will result in different readout signals and therefore different results. A given result will be influenced by the unique properties of each optical device array 21-26. This result may be particularly influenced by electromagnetic or other physical interactions occurring between a set of two or more interacting elements, including in particular the metasurface structure 12, the functionalization layer (if any), and the dielectric environment, such as a solvent or other medium.

[0043] Each readout key addresses the unique characteristics of each device. Therefore, by obtaining the readout key, the encrypted optical signal can be properly interpreted / decrypted. The readout key is usually unknown to the user who performs the optical characterization.

[0044] The present approach allows for two levels of security. First, the physical fingerprint is difficult, if not impossible, to clone so that each device 1, 1a-1c can be unambiguously identified. Second, the readout key can only be obtained for a duly identified device. The user may possibly also be authenticated in this process. Thus, only genuine devices (and possibly authenticated users) can cause the server and / or client devices to properly interpret the results obtained using the calibrated optical device.

[0045] All the above will be explained in detail below with reference to specific embodiments of the invention. Firstly, two cases or classes of embodiments can be distinguished. In the first case (see FIG. 5), the first and second data are read out by distinct characterization (or detection) steps S24, S25: a preliminary optical readout S22, S24 is performed before exposing the device to one or more analytes and performing a second readout S25 to obtain the second data. Typically, this preliminary optical readout is performed and processed efficiently (in a time of less than 100 ms). In the second case (see FIG. 6), a single characterization step S25a is sufficient. In both cases, the necessary characterization steps can be performed at the point of care, at home, in mobile care or according to any other suitable application context.

[0046] In a second case of embodiment (FIG. 6), a one-time read is performed, whereby the first and second data are obtained in a single characterization test (per device). The result of the characterization test is influenced by both the respective array characteristics and the physical fingerprint of each device. The readout key can then address both the distinct array characteristics and the physical fingerprint of each optical device of the optical devices 1, 1a-1c S15. The first and second data may be accessed as follows: first, characterization data corresponding to a characterization test performed using a given optical device is received S31, then the first and second data are determined S31 based on the received characterization data with the intention of identifying the given device 1 S32, and the associated readout key is obtained S33. Finally, the second data is interpreted S35 according to the obtained readout key, as shown in FIG. 6.

[0047] Figures 5 and 6 assume that steps S31, S31a, S33 and S34 are performed at the server, but in a variant such steps may be performed at the client device and the server may be used only to verify the device ID S32 and return the read key S33 in response to a query from the client device.

[0048] For example, if the physical fingerprint is part of (or is embodied or formed in some way by) the metasurface array, or is another part of the optical device that happens to detectably affect the characterization test, then a single characterization step may be sufficient, and in that regard the first and second data may possibly correspond to distinct characteristics of a single signal. In various variants, one of these characteristics may possibly be derived from the other (e.g., the first data may be a derivative of the second data). In all cases, the first data makes it possible to identify each device 1 S32 in order to obtain an associated readout key S33 and then interpret the second data S35 according to the obtained readout key.

[0049] Relying on a single characterization step (where both types of data are obtained) may be advantageous in some applications, as it simplifies the operations performed locally, e.g. at the point-of-care. However, such an embodiment may increase the complexity in data extraction. Whether the advantages of this approach outweigh the disadvantages must also be evaluated, taking into account that the preliminary optical readout (before sample exposure) required in the first class of embodiments (Figure 5) is usually easy and time-saving to perform. The preliminary optical readout can be performed, for example, at the time of starting the device, to ensure proper positioning of the optical device when implemented in a disposable cartridge.

[0050] The physical fingerprint is preferably an unclonable characteristic of the arrays 21-26 of each optical device 1. Such a characteristic may be referred to as a physical unclonable characteristic. This unclonable characteristic may have a physical and / or chemical origin. This physical and / or chemical characteristic may result, for example, from slight dimensional differences (e.g., uncontrollable or unintended) in the metasurface structures 12, whether in their geometry or morphology, chemical composition or chemical functionalization, or a combination thereof. The uncontrollable characteristic makes it more difficult (and indeed impossible) for a malicious user to replicate the optical device.

[0051] Variations in the unique physical fingerprint of an optical device array may further rely on uncontrollable properties of another portion of the optical device (i.e., distinct from the array) or even on physical anchors that are intentionally provided to and attached or integral with the optical device. The physical anchors may, for example, be permanently attached (contained) to the optical device, for example by a strong adhesive, or in such a manner that removing, destroying, or otherwise altering the optical device or its primary function is irreversibly altered. The anchors may also be incorporated into the body of the optical device in an unalterable manner.

[0052] Similar to the unique physical fingerprint discussed above, the physical anchor may, for example, include built-in security features (e.g., microprint, security ink, fluorescent dye, or hologram) and / or unclonable features. It is much more preferable that such physical anchors be attached to the optical device itself and not to the packaging, since the trust anchor is established for the object to which it is attached, i.e., the best protection is achieved for the actual object whose unique physical characteristics are utilized.

[0053] Physical anchors typically facilitate the realization of unique physical properties of the optical device and in a more systematic and controllable manner. Nevertheless, a unique physical fingerprint typically provides a higher degree of entropy, thereby making the physical fingerprint more difficult to clone. In contrast, intentionally placed physical anchors are more controllable and systematic, and therefore in principle easier to attack precisely. Therefore, the uniqueness of explicit physical anchors must be generated with some effort. In a variant that relies on intentionally added anchors, the unclonable properties can be characterized independently of the array, as envisaged in FIG. 5.

[0054] Nevertheless, in each of the above two cases (whether based on a unique fingerprint or on an added physical anchor), the physical property utilized preferably reflects an uncontrollable (or not fully controllable) manufacturing feature, i.e., a non-deterministic feature that is subject to some non-deterministic difference such that the property is non-cloneable, but is nevertheless detectable.

[0055] Other variations may rely on built-in security features (e.g., microprints, security inks, or holograms) rather than utilizing the unclonable properties of the array or deliberately added physical anchors. Such features are typically deterministic features that are nevertheless difficult to clone.

[0056] 2-4, the optical devices 1, 1a-1c each preferably include two or more arrays 21-26 of metasurface structures 12 that impart distinct properties to the optical devices 1, 1a-1c. The optical devices 1, 1a-1c are therefore distinct from one another. The distinct properties may result, for example, from controlled (i.e., intended) dimensional and / or compositional differences in the metasurface structures and / or coatings thereof, as described in more detail below.

[0057] Advantageously, metasurface structures can be fabricated with 1 nm precision by the preferred fabrication methods as described herein (see section 2.2). The resulting characteristics of the arrays can therefore be said to be deterministic in the sense that they will be different, but predictable, characteristics that will therefore give rise to different characterization results when optical characterization tests are performed. Thus, the optical devices can be deterministically assigned appropriate read-out keys, such keys containing codes according to which the results of the characterization tests can be correctly interpreted (i.e., decoded).

[0058] However, as mentioned above, arrays can also be affected by non-deterministic properties, in which case the array has some (or rather, inherently) deterministic and some non-deterministic properties, but read keys can be devised to deal with both kinds of properties.

[0059] In some embodiments, the metasurface structures 12 of at least one of the arrays 21-26 of the optical devices are coated S11 (see FIG. 4) with a substance for selectively binding the analyte. The substance forms a functionalization pattern of each of the arrays 21-26 of the optical devices 1, 1a-1c. The results captured by the second data for each optical device 1 are then influenced by both the metasurface structures 12 of the respective arrays 21-26 and by the functional pattern of each one of the functionalization patterns. Consistently, the readout key will address the respective functionalization pattern S15. That is, the optical devices 1, 1a-1c have distinct functionalization patterns, resulting in distinctly different deterministic properties, which act as the set secret. In variants, or in addition to these patterns, other well-controllable properties of the arrays 21-26 may be used, such as the geometry of the metasurface structures 12 as described above.

[0060] The substance can be, for example, a chemical receptor or other substance (e.g., a particle) for binding the analyte. However, the use of particles may be undesirable since particles may add additional variability that cannot be easily controlled, which may counteract the non-deterministic aspects otherwise provided. Thus, the substance preferably comprises molecular receptors 52-55 adapted to selectively bind the analyte of interest. That is, for each optical device of the set, the metasurface structure 12 of at least one of the corresponding arrays 21-26 may be coated with molecular receptors 52-55 S11. In this way, the arrays of optical devices 1, 1a-1c may be functionalized according to a functionalization pattern formed with molecular receptors 52-55. The arrays 21-26 of each optical device may be coated with possibly distinct types of molecular receptors 52-55 S11 so as to be able to selectively bind distinct types of analytes.

[0061] The molecular receptors are advantageously formed as molecular compounds 52-55 immobilized on the surface of the metasurface structure 12, as shown in Figure 4. Each of the molecular compounds 52-55 comprises several moieties, including a first moiety 50a immobilized on the top surface of the metasurface structure 12, and a second moiety 62-65 that is a molecular receptor with high binding affinity for a specific analyte. The receptors 62-65 are chemically bonded 50d to the first immobilized moiety 50a via a backbone 50b.

[0062] As further shown in FIG. 4, the moiety may further comprise a third moiety 50c. The third moiety 50c may be, for example, a protecting moiety for an analyte, for example comprising a redox-active naphthoquinone chromophore. The protecting moiety 50c is attached to the acetylene unit of the backbone 50b via an electrochemically cleavable bond. Thus, as shown in FIG. 4, the acetylene unit of the immobilized molecular compound must be deprotected S11, for example by electrochemically cleaving the protecting moiety before coupling a molecular receptor to the free acetylene unit. The resulting molecular compound can then be exposed to an analyte for optical characterization S25.

[0063] The deprotection mechanism can be based, for example, on electrochemical reduction of the protecting moiety. Single-electron reduction, oxidation, or accelerated two-electron mechanisms are preferred, as they are more efficient and require less electrochemical energy. The deprotection mechanism results in an analyte-functionalized surface, when the initially protected analyte unit is fixed to the surface via the backbone and the anchoring moiety. This therefore results in a chemically flexible attachment, which allows subsequent attachment of a variety of functional receptors to the cleaved compound, i.e., by chemically binding to the free acetyl.

[0064] For example, the metasurface structure 12 may be formed as a semiconductor structure 12, e.g., silicon, coated with molecular receptors formed as molecular compounds immobilized on the top surface of the metasurface structure 12 as described above. In a variant, for sensing applications, the structure 12 may be functionalized with antibodies, viruses or other types of particles, all of which can be immobilized directly (in a physisorption manner) or via compounds, to achieve a physisorption functionalized layer. The binding moieties 50d may also consist of antibodies, RNA, DNA, etc., for the purpose of selectively capturing various types of analytes by chemical binding interactions. As mentioned above, it is not necessary that all metasurface structures 12 of each optical device are functionalized. Besides chemical functionalization, the metasurface structures may also have metasurface-specific properties, e.g., for light manipulation.

[0065] A preferred optical characterization test is described in detail below. As shown in Fig. 1, the optical characterization test S25, S25a performed involves electromagnetic interaction, whereby the array of devices 1, 1a-1c is illuminated (i.e. irradiated) S25 with electromagnetic radiation, which causes a spectral response of the optical devices. Thus, the result of the optical characterization test S25, S25a may include optical data representative of the spectral response of each optical device. The second data (and possibly also the first data) are then extracted from this optical data.

[0066] In some embodiments, each array of each optical device 1 is illuminated with electromagnetic radiation (e.g., using a spectrally narrow light source) at a frequency that matches the resonant frequency of the metasurface structures 12 of the array in the absence of analyte. This narrow light source is focused at a specific frequency that matches the resonant frequency of the empty receptor metasurface layer. This procedure aims to take advantage of the inherent built-in spectroscopic properties of the dielectric metasurface, for example using extremely narrow absorption resonances. This allows replacing a spectrometer (and reading out the optical signal) when using a single narrow optical pulse or a combination of multiple spectrally distinct narrow optical pulses and a CMOS imager.

[0067] As envisaged in FIG. 1, a transmission configuration is preferred. In that case, the spectral response of each optical device 1 is a response to electromagnetic radiation transmitted through the optical device 1. In a variant, a reflection configuration may be used. In either case, the spectral response of the device 1 reflects a change in absorption caused by an effective change in the dielectric environment of the metasurface structures 12 in one or more of the arrays 21-26 of the optical devices 1. It may be desirable to selectively capture an analyte on a particular metasurface structure 12 in one or more of the arrays 21-26 of the optical devices 1 during absorption or transmission, and observe a shift in the absorption resonance upon chemical binding of the analyte to the metasurface structure 12 due to a particular analyte-binding molecular receptor. The optical resonance of the metasurface structure changes upon binding of the analyte. This allows label-free sensing measurements to be made without the use of radioisotopes, fluorescent dyes, etc., since the presence of the analyte directly affects the optical properties of the metasurface 12. Such an approach allows for higher sensitivity and higher spatial resolution, for example, compared to approaches based on localized surface plasmon resonance.

[0068] In some embodiments, the arrays are illuminated sequentially (one array at a time). Finally, the result of the optical characterization test may include several results, and the results obtained for each array are aggregated. In a variant, all arrays can be read out simultaneously, for example using a 2D CCD detector (with spatial resolution), which allows further energy differentiation. In another variant, for example, multiple optical tests are performed for each array to capture different analyte-receptor binding kinetics, generating a transient signal when the analyte binds to the receptor. This allows data analysis that addresses the binding kinetics as a discriminatory feature.

[0069] In some cases, several types of optical metasurface structures 12 can be contemplated on the same chip, such as dielectric metasurfaces, surface plasmon resonance (SPR) metasurfaces using gratings or nanohole arrays, for example localized SPR metasurfaces (using nanohole arrays, nanoantennas or nanostructures, for example, disposed on a substrate). Thus, several types of optical characterization tests can be contemplated on the same chip, such as non-resonant or resonant light scattering tests, light absorption tests, and light emission tests (again, either reflective or transmissive if the substrate is transparent) using dielectric or semiconductor (e.g., silicon) metasurface structures disposed on a substrate (either reflective or transmissive if the substrate is transparent).

[0070] A preferred architecture will now be described with reference to Figures 1 and 2. The method of the present application is preferably performed at least in part on a server 300. The server 300 can, for example, be in data communication with a set of client devices 200, 200a-200c, e.g. mobile devices. The client devices typically communicate with optical detection devices 100, 100a-100c (e.g. CCDs) that are used to perform the optical measurements (see Figures 1 and 2).

[0071] The server receives data from each of the client devices (typically asynchronously, i.e. at different times) S31 (see Fig. 2, Fig. 5 and Fig. 6). Each client device 200, 200a-200c is paired with a respective optical device 1, 1a-1c. Thus, based on the data received in step S31, the first data and the second data can be accessed by the server 300. This allows, in particular, the server to identify the corresponding optical device 1 based on the accessed first data (S32: Yes) and then interpret the second data according to the read key obtained according to the first data S35. The server may then send a report to the client device S36. For example, the server may send a message containing information about the solved result S36. If the identification fails (S32: No), the server may typically ask the user to repeat the characterization check S34, record the attempted identification, invite the user to use another device and / or block further attempts if necessary, etc., or a combination of these.

[0072] Upstream of the user action S20 and the server action S30, some preparatory work needs to be done, for example by the manufacturer before or during the commissioning of the optical device, as will be explained below with reference to figures 5 and 6. In some embodiments, the method includes a series of preparatory steps, again performed for each of the optical devices 1, 1a-1c of the set. Such preparatory steps include fabricating each optical device S11 such that the respective arrays 21-26 exhibit distinct characteristics. A read-out key is then devised and associated with each fabricated device S17. The read-out key addresses the specific characteristics of each optical device, including the deterministic characteristics of the arrays and possibly also the physical fingerprint. The key may ultimately be stored together with a unique identifier of each optical device, although in a variant the key may possibly serve as an identifier of the device.

[0073] After production S11, each optical device is characterized, for example by the manufacturer, in order to read out S14 its respective physical fingerprint, thus obtaining a corresponding digital fingerprint, which is associated with an identifier of the optical device and stored S17 so that the optical device can be unambiguously identified at a later time. If this fingerprint should influence a key, the key has to be devised taking this into account.

[0074] All data relating to the optical device may then be transferred to a dedicated database accessible, for example, from the server 300. This database may possibly be a distributed system, preferably configured as a shared ledger. The shared ledger may in particular be configured as a blockchain, more preferably as a business blockchain, such as the so-called Hyperledger Fabric or a similar blockchain.

[0075] As mentioned before, the read-out key addresses the individual characteristics of the optical device and may possibly also have the effect of a physical fingerprint. The use of the read-out key makes it possible to restore the correct interpretation of the results obtained by the corresponding device. For example, a read-out key may be used to recover the correct interpretation of the results obtained by a corresponding device having a distinctly different array and thus an affine shift of the read-out data s 1 , s 2 Two optical devices D 1 , D 2 For example, each shift function is s 1 (x)=2x+3 and s 2 (x)=3x+5. In that case, the corresponding read key is simply the corresponding inverse function, i.e., x 1 =(s 1 -3) / 2 and x 2 =(s 2 -5) / 3. Therefore, device D 1 , D 2 The read data obtained by {y 1} and {y 2} cannot be interpreted correctly without the corresponding key. The above example is intentionally simple, and actual read keys are typically more sophisticated. In general, such a key can be considered as some inverse transformation of the changes caused by the array. However, given that an inverse transformation is typically not analytically available for such changes, the read key may need to be tabulated or otherwise defined as a numerical function or algorithmic procedure. For example, in some cases the read key may be obtained as a cognitive model trained using machine learning or learned parameters of such a model.

[0076] An example will now be described with reference to Figs. 7(A)-7(C). Fig. 7(A) shows the theoretical bins estimated for a given optical device. That is, Fig. 7(A) assumes that a particular optical property can be realized by rational design of the metasurface arrays of an optical device including multiple metasurface arrays, in this example three metasurface arrays. The target property may be, for example, an optical wavelength resonance. The design takes into account the fabrication process and its tolerances such that the optical response of the fabricated metasurface structure will be located within a particular spectral bin (i.e. wavelength or energy interval), with each bin being spectrally sufficiently separated (in wavelength or energy) from adjacent bins. The design of the array further allows prediction of forbidden (unused) spectral ranges. The size of the bins is such that it accounts for errors in the metasurface fabrication (receptor functionalization, if any) and shifts caused by analyte binding during optical detection testing. That is, the bin width can be estimated to ensure that the actual characterization testing does not shift the target optical property outside the corresponding bin. The bin structure can therefore be viewed as a classification structure. The characteristics of the bin can act as an identifier for that given device.

[0077] The optical device is then fabricated to have deterministic optical properties as pre-planned during the design phase (Fig. 7(B)). Uncontrollable fabrication errors result in random shifts from the intended theoretical optical properties as predicted by the design. The same is true when metasurfaces are functionalized with receptors, since the receptors are to some extent uncontrollable at the microscopic level. For example, the local receptor surface density, the receptor orientation with respect to the surface, stacking properties, folding, etc. can affect the actual optical properties of the metasurface. All sources of error combine to deviate from the theoretical design properties R as initially estimated (Fig. 7(A)). i (i=A, B and C) results in an optical shift relative to the optical properties of the individual optical devices. After fabrication, the optical properties (taking into account the functionalization, if any) are read out for each individual optical device. This is done without exposing the device to a sample and before commissioning the device. The resulting inspection value R i,real is the value R i The obtained R i,real may be linked to a corresponding radio frequency identification (RFID) tag and stored in a database, for example.

[0078] Referring to FIG. 7(C), the user then performs a readout of the optical device (i.e., this corresponds to steps S22, S24 in FIG. 5) before using the optical device for a detection test with an analyte. This results in an optical characteristic that can be compared with the stored characteristic. Considering that the device may have undergone some slight changes (e.g., temperature may affect the molecular functionalization of the surface), the values ​​obtained by the user may vary slightly compared to the stored characteristic, and therefore, rather than using specific (exact) spectral data values, it is advantageous to use bins (ranges) for classification purposes. Nevertheless, the values ​​obtained by the user are recognizable as belonging to a specific bin and can be further used to identify the device and the corresponding readout key (e.g., bin position and signal shift due to the array, for example).

[0079] The above embodiment assumes that two measurements are performed by the user, a first measurement to identify the optical device before exposing the device to the analyte, and a second measurement to perform the test in the presence of the analyte, as described above with reference to FIG.

[0080] In a variant, a single characterization step may be sufficient if the same type of characterization test can be performed a first time during commissioning of the optical device and a second time by the user, as envisaged in Fig. 6. The result of this characterization test can then be influenced by both the physical fingerprint of the array and the deterministic properties of the analyte, i.e. involving both types of information in a single measurement.

[0081] For example, a device may be designed to produce a particular theoretical optical property for each array, e.g., a given optical resonance in the presence of a given analyte. The design can ensure that the ideal value of this property falls within a particular interval (bin) as described above. However, some deviation shifts to the theoretical optical property will typically be observed when performing characterization tests, such shifts being the result of uncontrollable non-deterministic properties resulting from, for example, the fabrication of the optical device. However, the set of shifts obtained for every array is typically unique and can be used to identify the device, as described above with reference to FIG. 6.

[0082] The obtained identification pattern can then be used to identify the optical device (e.g. at a server), which is associated with a unique ID before or during commissioning of the device, and the pair {UID, identification pattern} is stored. Later, when the user uses the device to perform a characterization test, the result of the characterization again contains deviations relative to the ideal optical properties, which are transformed in the identification pattern and transmitted to the server. The corresponding readout key is then identified and used to solve the resonance value measured by the user. In that case, only one characterization test needs to be performed by the user, the result of which contains both kinds of data, i.e. the first data corresponding to the physical fingerprint and the second data corresponding to the deterministic properties.

[0083] 7 envisions only three arrays, a real chip may typically contain n×n arrays, where in practice n is typically 6 or more. The output optical signals can be read out simultaneously, for example with a CCD detector having high energy resolution, or for example with a CMOS reader with lower energy selectivity but higher spatial resolution.

[0084] 3(A) and 3(B), each array of optical devices 1, 1a-1c preferably forms a pattern of repeating cells, each cell consisting of two metasurface structures 12. For purposes of illustration, the embodiment shown in Figures 2 and 3 assumes a very small array of 3x2 cells each (3x4 metasurface structures).

[0085] In some embodiments, the metasurface structure 12 is formed as a semiconductor layer structure arranged on a substrate. The semiconductor structures may for example each have a lateral dimension between 1 nm and 500 nm on average. The lateral dimension is measured parallel to the main surface of the substrate, i.e. parallel to the plane (x,z) of Figs. 1 and 3. In some embodiments, the lateral dimension is greater than 50 nm, with a standard deviation of the lateral dimension being less than 5 nm. The semiconductor structures may advantageously each have a vertical dimension between 10 nm and 500 nm on average. The vertical dimension is measured perpendicular to the main surface of the substrate. In some embodiments, the vertical dimension is greater than 100 nm, with a standard deviation of the vertical dimension being less than 5 nm. A manufacturing method such as that described in the section allows for an accuracy approaching 1 nanometer.

[0086] Another aspect relates to a computer program product for interpreting optical characterization tests performed using a set of optical devices 1, 1a-1c as described above. The computer program product includes a computer-readable storage medium having program instructions embodied therein, the program instructions being executable by a processing means (i.e., a processor) to cause the processing means to implement steps as described above with respect to the method of the present application. Such steps (and corresponding instructions to be executed) may be performed at least in part on the server 300, or may be performed jointly on the server and, for example, on a connected client device 200, 200a-200c. Additional details regarding such computer program products are provided in Section 2.3 below. Section 2.4 further describes computerized devices as typically involved in performing the method of the present application.

[0087] Although the above embodiments have been briefly described with reference to the accompanying drawings, these embodiments may accommodate several variations. Several combinations of the above features may be contemplated. Examples are provided in the following section.

[0088] 2. Specific Embodiments - Technical Implementation Details 2.1 Specific Embodiments In this section, a new type of cryptographic anchor adapted for a multi - analyte sensor system used in diagnostics is disclosed to ensure reliable, secure, and fraud - resistant (counterfeit - proof) operation. The concept of the proposed cryptographic anchor is particularly well - suited for IoT diagnostics based on dielectric metasurfaces, which can benefit from the secure read - out protocol realized via the cloud.

[0089] As explained in Section 1, this approach combines uncontrollable manufacturing - related physical fingerprints with a controlled manufacturing - related built - in security function through specific receptor surface functionalization that serves as a set secret. Such a function enables secure cryptographic read - out of diagnostic results via the cloud for any analysis / diagnostic operation performed on an analysis device (such as a laboratory spectrometer, a CMOS imaging device, or a mobile phone), thereby effectively preventing product counterfeiting and reuse.

[0090] The underlying optical device is designed as a sensing chip, and its configuration is - two (or more) arrays of plasmonic or dielectric metasurfaces 12 with defined geometries (such as bow - tie shape, rod - like, elliptical, disc - like, etc., not exactly the same), material compositions (such as metals, highly doped semiconductors, high - refractive - index dielectrics, 2D layer materials, not exactly the same), or morphologies (such as crystalline, polycrystalline, amorphous, etc.) or combinations thereof, where each component may be divided into multiple material segments in some cases, and - a receptor - based surface coated with molecular compounds fixed on each individual metasurface 12 to ensure functionalization and enable selective binding of the analyte (such as when forming a chemical bond with the analyte).

[0091] In some embodiments, the sensing chip further includes channels that allow the analyte to be deterministically transported to the metasurface array in gas or liquid phase (or phase mixture), or gas or liquid handling components such as filters, fluid mixing elements, reagent addition components, separation components, concentration components, or combinations thereof. Such chips may also include or be connected to pumps (passive or active), tubes, tube ports, exhaust ports, loading pads, electrical contact pads, electrical connectors (e.g., printed connectors), and the like.

[0092] The operation of the chip relies on electromagnetic exchange or coupling mechanisms between pairs of metasurfaces, between a metasurface and its respective receptor coating, or between a metasurface / coating and its dielectric environment, or combinations thereof, which give rise to collective optical effects. In some embodiments, operation further involves electromagnetic or dielectric field enhancement mechanisms through resonant coupling effects (e.g., collective Mie resonators).

[0093] Such sensing chips are used in sensing devices or systems as described below. The sensor chip is exposed to an analyte (e.g. from a solution or gas phase) so that the analyte can interact (functionalize) with the corresponding receptor that potentially binds at a specific location in an analyte-selective manner. Binding of the analyte changes the dielectric environment of the metasurface 12, thereby causing a shift in the absorption resonance. Such a shift can be read out using very simple optical means, e.g. a narrow light source focused at the resonance of the empty receptor-metasurface layer. Since most of the light is absorbed, the measured intensity at the detector is low. When the analyte is bound, the dielectric environment is changed, so that the absorption resonance of the metasurface shifts (usually towards higher wavelengths) and the previously absorbed light is now transmitted through the metasurface almost 100% thereby causing a significantly higher intensity at the detector.

[0094] For example, the chip may include a metasurface 12 functionalized with molecular receptors, a microchannel-based gas or liquid handling (e.g., capillary-driven) system, and an RFID chip, i.e., an RFID chip can be attached to the sensing chip and can be programmed or readable to identify the sensing chip by a UID.

[0095] The metasurface 12 can be fabricated with unprecedented precision by the fabrication methods disclosed in the next subsection, resulting in unprecedented unique optical properties of the metasurface, which can be used for receptor-less sensing, receptor-based sensing, or both.

[0096] This approach makes it possible to include both physical fingerprints and embedded security features, especially in metasurfaces.

[0097] As previously mentioned, physical fingerprints refer to material characteristics that are difficult or impossible to control, including differences in fabrication and / or composition. Differences can be seen specifically in geometric dimensions (length, width, thickness), material composition (uniform composition, non-uniform composition), material morphology, material crystallinity, and material functionalization.

[0098] While the above parameters can also be used as controllable deterministic features to be used as built-in security features for metasurfaces (see below), even minimal differences in nanofabrication or material composition can already produce detectable changes in the optical properties of the pristine metasurfaces. Such properties can be further characterized for each individual device and therefore used as intrinsic security features, i.e. physical fingerprints, that cannot be easily replicated, discovered or reverse engineered.

[0099] Below, by way of a non-exhaustive list, we give examples of different types of errors that occur in the fabrication or material composition of dielectric metasurface devices that can be used in the context of this application: material deposition errors, e.g. sputtering, MBE or ALD growth, chemical resist errors, surface contamination, mask contamination or defects, imprint errors or defects, dry etching errors, wet etching errors, anisotropic or isotropic effects, nucleation, crystal defects due to different etch rates, loading effects in ICP DRIE, or tapering, or combinations of these.

[0100] Most of the above effects are interdependent. For example, resist defects can affect the masking layer and the subsequent transfer step that uses that mask. These undesirable and uncontrollable phenomena typically occur in the case of true nanometer-scale fabrication, since it is not feasible to control all these processes or compositional processes at such a scale in conventional fabrication. However, metasurfaces are extremely vulnerable to the effects of such errors, since their optical properties are directly affected and altered accordingly.

[0101] Fortunately, such physical fingerprints can be characterized after manufacture and the detected fingerprints can be characterized for each particular sensing chip, stored, and later utilized to identify such devices as described in Section 1.

[0102] Except for the uncontrollable physical fingerprint, the underlying physical parameters can also be controlled to a great extent, resulting in built-in security features that can be used to tune the properties of the pristine metasurface and its functionalization, i.e., built-in security features of the metasurface can be realized.

[0103] As design parameters, the following parameters can be used for metasurfaces: geometric shape (circular, triangular, elliptical, rod-like, etc.), geometric dimensions (length, width, thickness), material composition (homogeneous composition, heterogeneous composition), material stacking, material morphology, and material crystallinity. Such properties can in principle be varied for each individual chip produced. However, e-beam written masters are mostly only changed for each VLSI-compatible nanoimprint master fabrication step, a necessity that depends on the economics and the security level requirements to be achieved. For example, different masters exist and are used in different ways in pick-and-place processes.

[0104] The above parameters can be varied at the wafer, array or subarray level, e.g., at the metasurface element level. Changing the geometry or dimensions as design parameters does not necessarily incur additional costs, whereas changing the material composition, morphology, crystallinity, etc., may be more complicated and therefore more costly.

[0105] Each multi-receptor sensing chip may comprise an array of metasurfaces, each with, for example, a different physical fingerprint and, optionally, a different built-in security function, forming, for example, a 6×6 matrix. In this way, a specific localized functionalization can also be used as a built-in security function. Such functions can be modified during the deposition of receptor compounds on the metasurface, using deposition processes based on microdrop casing, inkjet or nanoelectronic spraying, etc., as well as micro- and nanofluidic deposition methods. The receptor compounds used for diagnostic work must be present on at least one array element to capture the corresponding analyte, but additional built-in security functions can also be envisaged, besides the mere variable assembly.

[0106] Additional built-in security features may include, for example, receptor-empty array elements, receptor-masking compounds on array elements, non-selective receptor compounds, and redundant receptor types on other array elements (see Figures 2-3).

[0107] Functionalization can be varied during assembly of the compounds at the level of the sensing chip, for example using random generators. Given the large number of array elements (e.g. 6 × 6), the variety of molecular receptor types available, and the inherent entropy of the physical fingerprints used here, a huge combinatorial potential is available to create hardware-based cryptographic anchors. A given type of receptor may be required to detect a given target analyte. However, such receptors can be hidden for security reasons and masked by other types of receptors.

[0108] Other measures can be used to secure the readout process and prevent misuse of the sensing device (e.g. repeated use by resale), which physically separates the readout key from the sensing device. Such a security feature protocol can be used as a configured secret. It can be built into the software required to operate the optical detectors 100, 100a-100c. A preferred protocol is the following: the readout key is granted via the cloud only if certain conditions, which can be tracked in a database, are met, e.g. the sensing chip can be legitimately identified and it is confirmed that the chip has never been used before. This principle allows full control of the use of the IoT device. However, in some applications, the diagnostic results may be considered as sensitive data, and therefore only accessible by authorized users, patients, registered physicians, etc.

[0109] Given the high resolution and precision sensing capabilities realized by the present methods, a wide range of applications can be envisioned. Typical sensing applications include sensing of various compounds, multiplexed sensing, medical diagnostics, medication compliance, metabolic studies, environmental monitoring, analysis of exhaled breath (volatile organic compounds, metabolites, etc.), nanochemistry using educt and product analysis, photocatalytic engineering of sensing elements, and metabolomics, among others.

[0110] The optical device (sensing chip) of the present application can be used as a "mobile" device, particularly suitable for most frequent use in point-of-care, mobile emergency diagnostics, home medical diagnostics or mobile screening tests, where pre-diagnostic anamnestic tests are performed by a general practitioner or by the patient himself, or where the patient himself needs to perform tests very frequently (e.g. to adjust drug dosage according to metabolic activity), but may also be used in diagnostic clinical laboratories.

[0111] Medical diagnostic applications include myocardial infarction detection, stroke detection, HIV detection, sexually transmitted disease detection, Alzheimer's plaque detection, drug treatment compliance or adherence, drug treatment induced metabolic responses, and drug side effects, among others.

[0112] 2.2 Preferred Manufacturing Method The optical device is preferably obtained by a fabrication method, in which a layer structure with a semiconductor layer is processed to form a metasurface structure. The fabrication method relies on a layer structure comprising a substrate, a stack and a resist structure. The resist structures each comprise a resist material comprising a semiconductor element. The stack is arranged on the substrate. The resist structures form a pattern on the stack and can be realised by electron beam lithography (EBL) and / or nanoimprint lithography (NIL) methods. The stack comprises a semiconductor layer (arranged on the substrate), a protective layer (arranged on the semiconductor layer) and a transfer layer (arranged on the protective layer). The protective layer is preferably made of Al x O y and the transfer layer comprises, for example, SiO 2The laminated structure may for example be obtained by forming a laminate on a substrate, where a protective layer is deposited using a process such as atomic layer deposition, chemical vapor deposition, sputtering, etc.

[0113] The exposed portions of the transfer layer are removed by selectively etching the transfer layer. The exposed portions are the unmasked portions, i.e. the portions that are not masked by the resist structure. After removing the exposed portions, the residual portions of the transfer layer remain between the protective layer and the resist structure. It should be noted that a selective etching process is an etching process that is selective to the material to be removed (the transfer layer in the above case), i.e. an etching process in which the target material is removed much more efficiently than other exposed materials. The selectivity of an etching process typically ranges between 100 and 10,000.

[0114] The resist structure is then completely removed by a further selective etching process. As a result, the transfer layer structure formed by the remaining parts of the transfer layer is exposed. The transfer layer structure is then transferred to the protective layer by selectively etching the protective layer using a further selective etching process. In this way, a combined part of the residual layer parts is obtained, which respectively includes the remaining parts of the protective layer and the remaining parts of the transfer layer.

[0115] The semiconductor layer is then selectively etched to provide a residual semiconductor structure. For example, the semiconductor layer is preferably a BCL. 3The remaining semiconductor structures are then selectively etched using an inductively coupled plasma process based on the method described above. At this point, the remaining semiconductor structures are still masked by the combined portions of the previously obtained residual layer portions. The combined portions are therefore finally completely removed by selectively etching the combined portions. As a result, the semiconductor structures are exposed. In this way, metasurface structures are obtained, arranged according to the pattern initially formed by the resist structures on the initial stack. The above fabrication method can be carried out, for example, to obtain planar optical elements in which the metasurface is formed by the semiconductor structures.

[0116] The fabrication method described above relies on an indirect transfer process, resulting in unprecedentedly precise and clean metasurface structures. This is made possible by successive selective etching steps in a multi-stage multilayer approach, which allows the removal of resist structures while keeping the semiconducting layers protected, especially when the resist material contains semiconducting elements. Nevertheless, the method described above is compatible with both nanoimprint lithography (NIL) and electron beam lithography (EBL) methods. Thus, the resist structures can be initially obtained using a NIL process or an EBL process. The mold used to obtain the initial resist structures can therefore be used multiple times when using NIL, making the method compatible with mass production and operating at a significantly lower cost compared to sequential EBL patterning alone.

[0117] 2.3 Computer Program Products The invention may be a system, method, or computer program product, or combination thereof, of any possible level of technical detail of integration. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to implement aspects of the invention.

[0118] A computer readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device. A computer readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer readable storage media includes portable computer diskettes, hard disks, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read only memory (CD-ROM), digital versatile disk (DVD), memory sticks, floppy disks, mechanically encoded devices such as punch cards or ridge structures in grooves with instructions recorded thereon, and any suitable combination thereof. As used herein, computer-readable storage media should not be construed as being ephemeral signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., light pulses through a fiber optic cable), or electrical signals transmitted over wires.

[0119] The computer readable program instructions described herein may be downloaded from a computer readable storage medium into each computing / processing device or to an external computer or storage device over a network, such as the Internet, a local area network, a wide area network, or a wireless network, or a combination thereof. The network may include copper transmission cables, optical transmission fiber, wireless transmission, routers, firewalls, switches, gateway computers, or edge servers, or a combination thereof. A network adapter card or network interface in each computing / processing device receives the computer readable program instructions from the network and forwards the computer readable program instructions to a computer readable storage medium within the respective computing / processing device for storage.

[0120] The computer readable program instructions for carrying out the operations of the present invention may be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, configuration data for an integrated circuit, or source or object code written in any combination of one or more programming languages, including object oriented programming languages ​​such as Smalltalk, C++, and procedural programming languages ​​such as the C programming language, or similar programming languages. The computer readable program instructions may be executed entirely on the user's computer as a stand-alone software package, partially on the user's computer, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) may execute computer readable program instructions by personalizing the electronic circuitry using state information of the computer readable program instructions to carry out aspects of the invention.

[0121] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams that illustrate methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer readable program instructions.

[0122] These computer readable program instructions may be supplied to a processor of a general purpose computer, special purpose computer, or other programmable data processing device to effect a machine such that the instructions, executed by the processor of the general purpose computer, special purpose computer, or other programmable data processing device, form means for implementing the functions / operations specified in the blocks of the flowcharts and / or block diagrams. These computer readable program instructions may be stored in a computer readable storage medium capable of instructing a computer, programmable data processing device, or other device, or combination thereof, to function in a particular manner, such that the computer readable storage medium on which the instructions are stored comprises an article of manufacture including instructions that implement aspects of the functions / operations specified in the blocks of the flowcharts and / or block diagrams.

[0123] The computer readable program instructions may be loaded into a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, such that the instructions, which execute on the computer, other programmable apparatus, or other device, implement the functions / acts specified in the flowchart and / or block diagram blocks.

[0124] The flowcharts and block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of instructions, including one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur in a different order than that noted in the figures. For example, two blocks shown in succession may in fact be executed substantially in parallel, or the blocks may be executed in reverse order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, may be implemented by a dedicated hardware-based system that performs the specified functions or operations, or may embody a combination of dedicated hardware and computer instructions.

[0125] 2.4 Examples of suitable computerized units A computerized device may be suitably designed to implement embodiments of the invention as described herein. For example, it may include one or more computerized units, each including a general purpose computer. In an exemplary embodiment, in terms of the hardware architecture, the unit may include a processor, a memory coupled to a memory controller, and one or more input and / or output (I / O) devices (or peripherals) communicatively coupled via a local input / output controller. The input / output controller may be, but is not limited to, one or more buses or other wired or wireless connections as known in the art. The input / output controller may include additional elements such as controllers, buffers (caches), drivers, repeaters and receivers to enable communication, but are omitted for simplicity of illustration. The local interface may also include address, control and / or data connections to enable appropriate communication between the above components.

[0126] A processor is a hardware device for executing software, particularly software stored in a memory. A processor may be any custom or commercially available processor of several processors associated with a computer, a central processing unit (CPU), a coprocessor, a semiconductor-based microprocessor (in the form of a microchip or chip set), or in general, any device for executing software instructions.

[0127] The memory may include any one or combination of volatile memory elements (e.g., random access memory) and non-volatile memory elements. Also, the memory may incorporate electronic, magnetic, optical or other types or combinations of storage media. It is noted that the memory may have a distributed architecture, where various components are located remotely from one another but may be accessed by the processor.

[0128] The software in the memory may include one or more separate programs, each including an ordered list of executable instructions for implementing a logical function. In particular, the software in the memory may include the methods described herein according to the exemplary embodiments, and a suitable operating system (OS). The OS essentially controls the execution of other computer programs and provides scheduling, input / output control, file and data management, memory management, communication control and related services.

[0129] The methods described herein may be in the form of a source program, an executable program (object code), a script, or any other entity that contains a set of instructions to be executed. In the case of a source program form, the program must be translated through a compiler, assembler, interpreter, etc., which may or may not be contained in memory, as is well known, in order to operate properly in connection with the OS. The methods may also be written as an object-oriented programming language with classes of data and methods, or a procedural programming language with routines, subroutines, or functions, or a combination of these.

[0130] In some cases, a conventional keyboard and mouse may be coupled to the input / output controller. Other I / O devices may include other hardware devices.

[0131] Additionally, an I / O device may include a device that communicates both input and output. The computerized system may further include a display controller coupled to the display. In an exemplary embodiment, the system may further include a network interface or transceiver for coupling to a network. The network transmits and receives data between the computerized unit and an external system. The network is optionally implemented in a wireless manner using wireless protocols and technologies, such as, for example, WiFi, WiMax, etc. The network may be a fixed wireless network, a wireless local area network (LAN), a wireless wide area network (WAN), a personal area network (PAN), a virtual private network (VPN), an intranet, or other suitable network system, and includes equipment for transmitting and receiving signals.

[0132] The network may be an IP-based network for communication between a given unit and any external servers, clients, etc. over a broadband connection. In an exemplary embodiment, the network may be a managed IP network managed by a service provider. In addition, the network may be a packet-switched network such as a LAN, WAN, Internet network, etc.

[0133] If the unit is a PC, a workstation, an intelligent device, etc., the software in the memory may further include a Basic Input / Output System (BIOS), which is stored in ROM so that the BIOS can be executed when the computer starts up.

[0134] During operation of the unit, the processor is configured to execute software stored in the memory to communicate data to and from the memory and to generally control the operation of the computer in accordance with the software. The methods and OS described herein are read, in whole or in part, by the processor and typically buffered within the processor before execution. When the methods described herein are implemented in software, the methods can be stored in any computer-readable medium, such as storage, for use by or in association with any computer-related system or method.

[0135] Cloud Computing in General Although this disclosure includes detailed descriptions of cloud computing, it should be understood that implementation of the teachings described herein is not limited to cloud computing environments. Rather, embodiments of the invention may be implemented in conjunction with any other type of computing environment now known or later developed.

[0136] Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal administrative effort or interaction with a service provider. The cloud model may include at least five characteristics, at least three service models, and at least four deployment models.

[0137] Its features are as follows. On-Demand Self-Service: Cloud consumers can unilaterally provision computing capacity, such as server time and network storage, automatically as needed, without the need for human interaction with the service provider.

[0138] Broad network access: Functionality is available over the network and is accessed through standard mechanisms that facilitate use by heterogeneous thin-client or thick-client platforms (e.g., cell phones, laptops, and PDAs).

[0139] Resource Pooling: To serve multiple consumers using a multi-tenant model, a provider's computing resources are pooled, and different physical and virtual resources are dynamically allocated and reallocated depending on demand. Consumers generally have no control or knowledge over the exact location of the resources provided, but there is a sense of location independence in that it may be possible to specify a higher level of abstraction of location (e.g., country, state, or data center).

[0140] Rapid Elasticity: Rapid, elastic, and sometimes automatically provisioning capabilities to rapidly scale out, and rapid release of capabilities to rapidly scale in. To the consumer, the capabilities available for provisioning often appear infinite, and they can be purchased at any time, as much as they want.

[0141] Metered Services: The cloud system automatically controls and optimizes resource utilization by utilizing metering capabilities at some level of abstraction appropriate for the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, giving both providers and consumers transparency of the services utilized.

[0142] The service model is as follows: Software as a Service (SaaS): The functionality provided to the consumer is the use of the provider's applications running on a cloud infrastructure. The applications are accessible from a variety of client devices through thin-client interfaces such as web browsers (e.g., web-based email). The consumer has no management or control over the underlying cloud infrastructure, including the network, servers, operating systems, storage, or even individual application functions, with the possible exception of limited user-specific application configuration settings.

[0143] Platform as a Service (PaaS): The capability offered to the consumer is to deploy consumer-created or acquired applications, written using programming languages ​​and tools supported by the provider, on a cloud infrastructure. The consumer does not manage or control the underlying cloud infrastructure, including networks, servers, operating systems, or storage, but does have control over the deployed applications and, in some cases, the application hosting environment configuration.

[0144] Infrastructure as a Service (IaaS): The capability provided to the consumer is to provision processing, storage, network and other basic computing resources onto which the consumer can deploy and run any software, which may include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure, but has control over the operating systems, storage, deployed applications, and possibly limited control over selected network components (e.g., host firewalls).

[0145] The deployment model is as follows: Private Cloud: This cloud infrastructure is operated solely for the organization. It can be managed by the organization or a third party and can exist on-premise or off-premise.

[0146] Community Cloud: This cloud infrastructure is shared by several organizations to support a specific community with shared concerns (e.g., mission, security requirements, policies, and compliance concerns). It can be managed by the organization or a third party and can reside on-premise or off-premise.

[0147] Public Cloud: This cloud infrastructure is available to the public or large industry organizations and is owned by an organization that sells cloud services.

[0148] Hybrid Cloud: This cloud infrastructure is a composite of two or more clouds (private, community, or public) that remain their own entity but are joined by standardized or proprietary technologies that enable data and application portability (e.g., cloud bursting for load balancing between clouds).

[0149] Cloud computing environments are service-oriented with a focus on statelessness, loose coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure that includes a network of interconnected nodes.

[0150] 8A, an exemplary cloud computing environment 850 is illustrated. As shown, the cloud computing environment 850 includes one or more cloud computing nodes 810 with which local computing devices used by cloud consumers, such as, for example, a personal digital assistant (PDA) or mobile phone 854A, a desktop computer 854B, a laptop computer 854C, or an automobile computer system 854N, or combinations thereof, can communicate. The nodes 810 can communicate with each other. The nodes 810 may be physically or virtually grouped (not shown) in one or more networks, such as a private cloud, a community cloud, a public cloud, or a hybrid cloud, or combinations thereof, as described above. This enables the cloud computing environment 850 to provide infrastructure, platform, and / or software as a service for which the cloud consumer does not need to maintain resources on a local computing device. It should be understood that the types of computing devices 854A-854N shown in FIG. 8A are intended to be illustrative only, and that computing node 810 and cloud computing environment 850 may communicate with any type of computerized device via any type of network connection and / or network addressable connection (e.g., using a web browser).

[0151] Referring now to Figure 8B, a set of functional abstraction layers provided by cloud computing environment 850 (Figure 8A) is shown. It should be understood in advance that the components, layers and functions shown in Figure 8B are intended to be illustrative only, and embodiments of the present invention are not limited thereto. As shown, the following layers and corresponding functions are provided:

[0152] Hardware and software layer 860 includes hardware and software components such as mainframes 861, reduced instruction set computer (RISC) architecture based servers 862, servers 863, blade servers 864, storage devices 865, and networks and networking components 866. In some embodiments, software components include network application server software 867 and database software 868.

[0153] The virtualization layer 870 provides an abstraction layer that can instantiate virtual entities such as: virtual servers 871, virtual storage 872, virtual networks including virtual private networks 873, virtual applications and operating systems 874, and virtual clients 875.

[0154] In one implementation, the management layer 880 may provide the following functions: Resource provisioning 881 provides dynamic procurement of computing and other resources utilized to execute tasks within the cloud computing environment. Metering and pricing 882 provides cost tracking as resources are utilized within the cloud computing environment and billing or invoicing for the consumption of these resources. In one embodiment, these resources may include application software licenses. Security provides identity verification for cloud consumers and tasks and protection of data and other resources. User portal 883 provides consumers and system administrators with access to the cloud computing environment. Service level management 884 provides cloud computing resource allocation and management to ensure required service levels are met. Service Level Agreement (SLA) planning and fulfillment 885 provides advance arrangement and procurement for cloud computing resources in anticipation of future demand according to SLAs.

[0155] The workload tier 890 provides examples of functions that can utilize a cloud computing environment. Examples of workloads and functions that can be delivered from this tier include mapping and navigation 891, software development and lifecycle management 892, virtual classroom instructional delivery 893, data analytics processing 894, transaction processing 895, and mobile desktop 896.

[0156] Although this disclosure refers to cloud computing, it should be understood that implementation of the teachings described herein is not limited to cloud computing environments. Rather, embodiments of the present invention may be implemented in conjunction with any other type of computing environment now known or later developed. Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal administrative effort or interaction with a service provider. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models.

[0157] Although the present invention has been described with reference to a limited number of embodiments, variants, and accompanying drawings, those skilled in the art will recognize that various modifications can be made and equivalents can be substituted without departing from the scope of the present invention. In particular, features (device-like or method-like) described in a given embodiment, variant, or illustrated in a drawing may be combined or substituted with other features in another embodiment, variant, or drawing without departing from the scope of the present invention. Thus, various combinations of the features described with respect to any of the above embodiments or variants that remain within the scope of the appended claims are contemplated. Also, many minor modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope of the invention. Thus, the invention is not limited to the specific embodiments disclosed, but it is intended to include all embodiments that fall within the scope of the appended claims. Moreover, many other variations other than those expressly mentioned above can be contemplated.

Claims

1. 1. A method of interpreting an optical characterization test performed using a set of devices, comprising: each device of said set of devices one or more arrays of optical metasurface structures; each array having distinctly different properties; The method further comprising: for each device of the set: accessing first and second data capturing a physical fingerprint of each device and results of an optical characterization test performed using each device, respectively, the results being affected by a respective one of the distinct characteristics; identifying each device based on the accessed first data to obtain a read key associated with the identified device, the read key addressing the respective one of the distinct characteristics; interpreting the second data according to the read key to interpret the result of the optical characterization test; and transmitting the results of the optical characterization inspection to an inspection device.

2. the results being influenced by both the respective ones of the distinct characteristics and the physical fingerprint of each device; the read key addresses both said respective ones of said distinct characteristics and said physical fingerprint of each device; Accessing the first and second data includes: Receiving characterization data; 2. The method of claim 1, comprising: determining the first and second data based on the received characterization data with the intent of identifying each device to obtain the associated read key and interpreting the second data according to the obtained read key.

3. The method of claim 2 , wherein the physical fingerprint is a non-clonable characteristic of the one or more arrays of each device.

4. 10. The method of claim 1, wherein each of the devices in the set comprises two or more arrays of metasurface structures having the distinctly different properties such that the devices in the set are different from one another.

5. the metasurface structures of at least one of the arrays of each device are coated with a substance for selectively binding an analyte, the substance forming a functionalization pattern of each of the arrays of the device; the results captured by the second data are influenced, for each device, by both the metasurface structure of the respective array of each device and a respective one of the functionalization patterns; The method of claim 4 , wherein the read key addresses the respective one of the functionalization patterns.

6. 6. The method of claim 5, wherein the material comprises a molecular receptor for selectively binding the analyte, and the metasurface structures of at least one of the arrays of each device are coated with the molecular receptor such that the array of devices is functionalized according to a respective functionalization pattern formed by the molecular receptor.

7. 7. The method of claim 6, wherein two or more of the arrays on each device are coated with distinct types of molecular receptors for selectively binding distinct types of analytes.

8. 7. The method of claim 6, wherein the receptors are formed as molecular compounds immobilized on the surface of the one or more metasurface structures, each of the molecular compounds comprising several moieties including a first moiety immobilized on the surface and a second moiety that is a receptor chemically bonded to the first moiety via a backbone.

9. the number of moieties further includes a third moiety that is a protecting moiety for acetylene, the protecting moiety being attached to the acetylene unit of the backbone of each of the molecular compounds via an electrochemically cleavable bond; 9. The method of claim 8, wherein the method further comprises deprotecting the acetylene unit of the backbone of the molecular compound by electrochemically cleaving a protected portion of the molecular compound, and then coupling the molecular receptor to the deprotected acetylene unit.

10. The method of claim 1 , wherein the results of the optical characterization testing include optical data representative of a spectral response of each device.

11. 11. The method of claim 10, further comprising, for each device, prior to accessing the first data and the second data, performing the optical characterization inspection by illuminating each array of each device with electromagnetic radiation in the absence of an analyte at a frequency that matches a resonant frequency of the metasurface structure of the array.

12. 11. The method of claim 10, wherein the spectral response is a response to electromagnetic radiation transmitted through each device, and the spectral response reflects a change in absorption resonance caused by an effective change in the dielectric environment of the metasurface structures in one or more of the arrays of devices.

13. The method is performed at a server in data communication with a set of client devices; 2. The method of claim 1, further comprising, for each device, receiving data from one of the client devices paired with each device before accessing the first data and the second data, the first data and the second data being accessible by the server based on the received data, so that the server identifies each device based on the accessed first data and interprets the second data according to the obtained read key accordingly.

14. 14. The method of claim 13, further comprising sending a message to the one of the client devices after identifying each device and interpreting the second data to interpret the result of the optical characterization inspection, the message including information regarding the interpreted result.

15. for each device of the set, prior to accessing the first data and the second data for any of the devices of the set; fabricating each device such that the one or more arrays in each device have a respective one of the distinct characteristics; The method of claim 1 , further comprising: associating the read key for the respective one of the distinct characteristics with an identifier for each device.

16. 16. The method of claim 15, further comprising, after production of each device and before accessing the first data and the second data for any of the devices of the set, reading the physical fingerprint of each device to obtain a digital fingerprint corresponding to the physical fingerprint, and associating the digital fingerprint with the identifier of each device.

17. 10. The method of claim 1 , wherein each array of devices comprises a pattern of repeating cells each consisting of two metasurface structures.

18. The metasurface structure is formed as a semiconductor structure disposed on a substrate; 10. The method of claim 1, wherein the semiconductor structures each have an average lateral dimension between 1 nm and 500 nm, the lateral dimensions being measured parallel to a major surface of the substrate.

19. 20. The method of claim 18, wherein the semiconductor structures each have a vertical dimension that is between 10 nm and 500 nm on average, with a standard deviation of the vertical dimensions being less than 5 nm, the vertical dimensions being measured perpendicular to the major surface of the substrate.

20. 1. A computer program for interpreting optical characterization studies performed using a set of devices, each including one or more arrays of electromagnetic metasurface structures, the devices being tuned such that each array of devices has distinctly different characteristics, the computer program causing a computer to: accessing first and second data capturing a physical fingerprint of each device and results of an optical characterization test performed using each device, respectively, the results being affected by a respective one of the distinct characteristics; identifying each device based on the accessed first data to obtain a read key associated with the identified device, the read key addressing the respective one of the distinct characteristics; interpreting the second data according to the read key to interpret the result of the optical characterization test; and transmitting the results of the optical characterization inspection. Computer program.

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