Optical device

Abstract

The present disclosure discloses an optical device, comprising: a filter configured to filter light of a specific wavelength, the filter comprising at least one filtering working side; and a metasurface functional layer disposed on the at least one filtering working side of the filter or a surface opposite to the filtering working side. The filter is an indispensable core component in the optical device, and the metasurface functional layer is limited to processing characteristics and can only be prepared on a planar substrate. Based on this characteristic, by integrating the metasurface directly on the surface of the filter, the overall thickness of the device can be effectively reduced.

Description

Technical Field

[0001] This disclosure generally relates to the field of optoelectronic device technology. More specifically, this disclosure relates to an optical device. Background Technology

[0002] There are two main ways to fabricate traditional metasurface optical devices: one is to directly fabricate metasurface functional layers on a glass substrate; the other is to first fabricate metasurface functional layers on a silicon wafer and then transfer them to the glass surface through bonding technology to finally form optical devices with metasurface structures.

[0003] In traditional solutions, due to factors such as the glass's shatter resistance and processing difficulty, the thinnest glass substrate used is typically 0.21 μm. However, this substrate thickness has no practical effect on optical performance, but it can limit applications with strict requirements on device thickness, thus restricting the device's applicability. Utility Model Content

[0004] In order to at least address one or more of the technical problems mentioned above, this disclosure proposes an optical device.

[0005] In the first aspect, this disclosure provides an optical device comprising: A filter configured to filter light of a specific wavelength, the filter including at least one filtering working side; and a metasurface functional layer disposed on at least one filtering working side of the filter or on a surface opposite to the filtering working side.

[0006] In some embodiments, the optical device further includes an antireflection layer disposed on the surface of the metasurface functional layer opposite to the filter, for reducing reflection when light enters the optical device.

[0007] In some embodiments, the filter includes: a resin substrate; and a first coating layer and a second coating layer located on opposite sides of the resin substrate, the first coating layer and the second coating layer being configured to filter light of a specific wavelength, and the first coating layer and the second coating layer respectively constituting two filtering working sides of the filter.

[0008] In some embodiments, the filter is configured to filter infrared light.

[0009] In some embodiments, the metasurface functional layer is a TiOx and SiO2 mosaic structure layer.

[0010] In some embodiments, the TiOx and SiO2 mosaic structure layer is composed of alternating TiOx portions and SiO2 portions, wherein each TiOx portion and SiO2 portion is in contact with the filter.

[0011] In some embodiments, the material of the metasurface functional layer at the edge of the optical device is SiO2.

[0012] In some embodiments, the alternating TiOx and SiO2 portions have the same height, ranging from 150 to 600 nm.

[0013] In some embodiments, the thickness of the resin substrate is less than 0.21 micrometers.

[0014] In some embodiments, the thickness of the resin substrate is 0.11 micrometers.

[0015] Optical filters are an indispensable core component in optical devices, while metasurface functional layers, due to processing limitations, can only be fabricated on planar substrates. Based on this characteristic, by directly integrating the metasurface onto the surface of the optical filter, an integrated design can effectively reduce the overall thickness of the device. Attached Figure Description

[0016] The above and other objects, features, and advantages of exemplary embodiments of this disclosure will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this disclosure are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 A schematic diagram of an optical device according to one embodiment of this disclosure is shown; Figure 2 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown; Figure 3 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown; Figure 4 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown; Figure 5 A schematic diagram of a metasurface functional layer according to an embodiment of this disclosure is shown; Figure 6 A schematic diagram of a metasurface functional layer according to yet another embodiment of this disclosure is shown. Detailed Implementation

[0017] The technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, not all of them. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0018] It should be understood that the terms “comprising” and “including” used in this disclosure and claims indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure. As used in this disclosure and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this disclosure and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0020] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0021] The specific embodiments disclosed herein will now be described in detail with reference to the accompanying drawings.

[0022] Figure 1 A schematic diagram of an optical device according to one embodiment of this disclosure is shown.

[0023] like Figure 1 As shown, the core structure of this optical device consists of two parts: The first component is the filter 120, whose core function is to precisely filter specific wavelengths in incident light (e.g., selectively transmit visible light, cut off infrared light, or ultraviolet light). This filter is composed of a substrate 122 and a first coating layer 121. The substrate 122 serves as the supporting structure (typically made of light-transmitting materials such as resin), while the first coating layer 121 acts as the working side for filtering. It achieves the selection of target wavelengths through principles such as thin-film interference or material absorption, and is the core execution layer for the filtering function.

[0024] Based on the principle of thin-film interference, the coating layer is typically composed of multiple layers of transparent materials with different refractive indices (such as oxides and fluorides) stacked alternately. When light is incident on the coating layer, the reflected and transmitted light at different interfaces will interfere due to the optical path difference. By designing the material combination, thickness, and number of layers of the coating layer, light of the target wavelength can be efficiently transmitted due to constructive interference, while non-target wavelengths are suppressed due to destructive interference, thereby achieving selective filtering of specific wavelength bands (for example, common antireflective coatings and cutoff filters often use this principle).

[0025] Based on the principle of material absorption, the coating layer can be made of materials doped with specific ions. The molecular or atomic structure of these materials will selectively absorb photons of specific energy (corresponding to specific wavelengths). For example, the material in the ultraviolet absorption film can absorb short-wave ultraviolet light, while the infrared absorption film absorbs photons in the infrared band, thereby allowing non-absorbed target wavelength light to pass through, thus achieving a filtering effect.

[0026] Second, there is a metasurface functional layer 110, which is directly disposed on the surface of the first coating layer 121 of the filter 120. This design makes full use of the planar characteristics of the first coating layer 121, because the metasurface functional layer needs to rely on a planar substrate to complete the processing and fabrication of the nanostructure. Integrating it on the functional surface of the filter, which is an indispensable core component in optical devices, eliminates the need to introduce a new substrate and allows the metasurface (such as realizing functions like beam deflection, focusing, or wavefront modulation) to work synergistically with the filtering function. While ensuring the optical performance of the device, it significantly simplifies the overall structure.

[0027] The substrate 122 can be made of resin material to form an ultra-thin resin substrate with a thickness designed to be less than 0.21 micrometers. This size breaks through the 0.21-micrometer lower limit commonly used for traditional glass substrates due to considerations of breakage resistance and processing difficulty, and can significantly reduce the contribution of the substrate to the overall thickness of the device.

[0028] Specifically, the thickness of the resin substrate can be further optimized to 0.11 micrometers. This ultra-thin size fully utilizes the good flexibility and processability of the resin material itself (it is easier to achieve micrometer-level or even submicrometer-level ultra-thin molding compared to glass), and at the same time, it can minimize the physical footprint of the substrate itself in the optical path while ensuring stable support for the filter coating layer and metasurface functional layer. It is especially suitable for miniaturized optical modules with strict limitations on device thickness (such as mobile phone cameras, micro sensors, etc.), and provides key support for the lightweight and thin design of the overall structure.

[0029] Figure 2 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown. Figure 2 The optical devices shown are Figure 1The core difference in their optical devices lies in the placement of the metasurface functional layer 110. Figure 2 In the structure, the metasurface functional layer is not like Figure 1 Instead of being located on the filtering working side of the filter (i.e., the surface of the first coating layer 121), it is disposed on another surface of the filter opposite to the filtering working side.

[0030] Specifically, the filter 120 still consists of a substrate 122 and a first coating layer 121, which serves as the core of the filter. The side containing the first coating layer 121 is the working side that directly performs the filtering function. Figure 2 In this configuration, the metasurface functional layer 110 is transferred to the surface of the substrate 122 that is away from the first coating layer 121 (i.e., the opposite side of the working filter side). This layout adjustment also utilizes the planar characteristics of the substrate surface to meet the processing requirements of the metasurface. At the same time, by placing the metasurface and the working filter side on opposite sides of the filter, the overall performance of the device can be optimized according to the actual optical path design (such as the direction of incident light, interference avoidance between functional layers, etc.). For example, it can reduce the potential physical or optical interference of the metasurface nanostructure to the filter coating layer, or better adapt to the beam modulation sequence in a specific optical path.

[0031] Figure 3 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown. Figure 3 The optical devices shown are Figure 1 The core difference of the optical devices lies in the fact that the structure of the filter is more complex. In addition to the substrate 122, it also includes a second coating layer 123 as the working side of the filter, and both the first coating layer and the second coating layer have the function of filtering.

[0032] Specifically, Figure 1 The filter in the image uses only the first coating layer 121 as a single filtering working side, while Figure 3 While retaining the substrate 122 as a supporting base, the filter explicitly includes the second coating layer 123 in the scope of the filtering working side. This means that the second coating layer 123 also undertakes the filtering function, and it can work synergistically with the first coating layer 121 (for example, by combining different film systems, more complex spectral filtering effects can be achieved, such as broadening the filtering band, enhancing the cutoff depth of a specific wavelength, or achieving double-sided filtering to adapt to incident light from different directions).

[0033] Meanwhile, the metasurface functional layer 110 is still in place. Figure 1 The logic is that it is integrated into the filtering working side surface of the filter (here, the surface of the first coating layer 121). This design, while maintaining the advantages of integrating the metasurface and filtering function, allows the filter to achieve more flexible and comprehensive filtering performance by adding a second coating layer as the filtering working side, thereby adapting to more diverse optical scenario requirements.

[0034] Figure 4 A schematic diagram of an optical device according to yet another embodiment of this disclosure is shown.

[0035] Figure 4 The optical devices shown are Figure 3 The core difference of the optical device is that it adds an anti-reflection layer 130 to the original structure. This anti-reflection layer is specifically set on the surface of the metasurface functional layer 110 away from the filter, and is used to reduce the reflection loss when light is incident on the optical device.

[0036] Specifically, Figure 3 The optical components already include a filter (containing a substrate 122, a first coating layer 121, and a second coating layer 123) and a metasurface functional layer 110 integrated on the surface of the first coating layer 121. Figure 4 By adding an antireflection layer 130 to the outer side of the metasurface functional layer (i.e., the side opposite to the filter), the optical performance of the device is further optimized. When external light first enters the metasurface functional layer, the difference in refractive index between its nanostructure and air may cause some light to be reflected. The antireflection layer is typically composed of single or multiple layers of low-refractive-index materials (such as silicon dioxide, magnesium fluoride, etc.). By designing the film thickness, destructive interference is generated in the reflected light, thereby reducing the interface reflectivity and allowing more light to pass through the metasurface functional layer into the filter, reducing light energy loss or stray light interference caused by reflection. Alternatively, when light propagates outward from the metasurface functional layer as outgoing light, the abrupt change in refractive index between its nanostructure and air may cause some light to be reflected back into the device, resulting in unnecessary energy loss or secondary interference. The antireflection layer, through specific material combinations (such as low-refractive-index thin films) and thickness design, utilizes the interference effect of light to cancel interface reflection, allowing more effective light to escape smoothly and further improving the optical transmission efficiency of the device.

[0037] This design retains Figure 3 While integrating the advantages of the super-super surface and the double-coated filter, it improves the utilization rate of light by specifically suppressing reflection at the incident or emitting end, making it especially suitable for scenarios with high light flux requirements (such as imaging systems, photodetectors, etc.).

[0038] Figure 5 A schematic diagram of a metasurface functional layer according to an embodiment of this disclosure is shown.

[0039] like Figure 5 As shown, the metasurface functional layer 110 adopts an inlay structure layer of TiOx (titanium oxide, such as TiO2, Ti2O3, etc.) 1102 and SiO2 (silicon dioxide) 1101. That is, the two materials are combined with each other in a periodic array or composite arrangement at the nanoscale to form a functional structure that combines the characteristics of both.

[0040] TiOx, with its high refractive index and excellent optical control capabilities, allows for precise modulation of the phase and polarization state of incident light through the shape, size, and distribution of its nanostructures. SiO2, as a low-refractive-index material, not only possesses excellent light transmittance but also provides a stable support framework for the TiOx structure. Furthermore, the refractive index difference between the two materials enhances the interaction of the light field at the interface, improving the metasurface's efficiency in manipulating light. This inlaid structure design leverages the core role of TiOx in light modulation while optimizing overall performance through the stability and optical compatibility of SiO2. This enables the metasurface functional layer to efficiently perform specific functions such as beam deflection, focusing, and wavefront shaping, and is suitable for ultra-thin integration with filters.

[0041] The refractive index of TiOx is in the range of 2.1 to 2.6, and this range is closely related to its chemical composition and preparation process.

[0042] From a material type perspective, the ratio of titanium to oxygen (i.e., the stoichiometric ratio) in TiOx is crucial. For example, titanium dioxide (TiO2) typically has a higher refractive index (close to 2.6), while sub-titanium oxides (such as Ti2O3 and TiO) with lower oxygen content may have a refractive index tending towards the 2.1-2.3 range. Furthermore, the crystal structure of the material (such as the rutile or anatase phase of TiO2) also affects the refractive index. Differences in atomic density among different crystal forms lead to different light propagation speeds, thus altering the refractive index value.

[0043] From the perspective of preparation temperature, during thin film deposition (such as magnetron sputtering, electron beam evaporation, etc.), temperature affects the crystallinity and density of TiOx. Higher deposition temperatures usually promote grain growth, making the material structure denser and thus increasing the refractive index; while TiOx prepared at low temperatures may have a relatively low refractive index due to small grains or the presence of more pores.

[0044] The refractive index of SiO2 (silicon dioxide) is related to its crystal structure, preparation process, and the wavelength of the incident light. The common refractive index ranges in optical applications are as follows: Fused silica (amorphous SiO2): With a refractive index of approximately 1.458 in the visible light band (such as 550nm wavelength), it is one of the most commonly used SiO2 forms in the field of optics. Due to its excellent light transmittance and stable refractive index, it is often used as an optical thin film, lens or substrate material.

[0045] Crystalline quartz (such as α-quartz): Due to its anisotropy, the refractive index varies slightly along different crystal axes, and is approximately 1.544 (ordinary light) and 1.553 (extraordinary light) in the visible light band.

[0046] In addition, the refractive index of SiO2 varies slightly with wavelength (dispersion characteristics). For example, the refractive index is about 1.50 in the ultraviolet band (200nm) and drops to about 1.45 in the infrared band (1000nm), but the overall fluctuation is small. It is a low refractive index and high stability optical material. This characteristic makes it often used as a support or spacer material in metasurface functional layers to form a refractive index difference with the high refractive index TiOx and enhance the light field modulation effect.

[0047] Specifically, such as Figure 5 As shown, the TiOx and SiO2 mosaic structure layers are designed with alternating arrangements, meaning that TiOx and SiO2 portions are alternately distributed laterally. It is noteworthy that in this alternating structure, each individual TiOx portion and each individual SiO2 portion is in direct contact with the surface of the filter below. In other words, the nanostructure units of the two materials are not stacked in layers, but are arranged alternately in the same plane, and their respective bottoms form a direct physical connection with the filter (such as the coating layer on the working side of the filter).

[0048] This design allows the high refractive index modulation characteristics of TiOx and the low refractive index support characteristics of SiO2 to be evenly distributed within the same functional layer. At the same time, the direct contact between the two and the filter reduces the light loss caused by the intermediate interface, enhances the structural stability between the metasurface functional layer and the filter, and is more conducive to the synergistic effect of the two in optical performance (such as the precise modulation of light by TiOx and the spectral screening of the filter forming an efficient combination).

[0049] In addition, such as Figure 5 As shown, the material of the metasurface functional layer at the edge of the optical device is SiO2.

[0050] In the fabrication of metasurface functional layers, a common process is to first fabricate a SiO2 substrate framework and then fill it with TiOx. Specifically, a periodically arranged SiO2 nanostructure framework is first fabricated on the filter surface using photolithography, etching, or other methods, forming an array with reserved filling spaces. Subsequently, TiOx material is precisely filled into the gaps between the SiO2 framework using deposition processes (such as atomic layer deposition, magnetron sputtering, etc.), ultimately forming a structure where TiOx and SiO2 are alternately interwoven.

[0051] Due to this frame-then-filling process, in the outermost region of the device, the SiO2 frame structure naturally extends to the boundary, while the TiOx filling range is limited by the reserved space inside the frame. This means there are no gaps at the edges for TiOx filling, thus only SiO2 material is ultimately retained. This structural characteristic ensures the orderly inlay of the two materials in the central region of the functional layer to achieve optical modulation, while also providing better structural stability and optical compatibility at the edges due to the presence of only SiO2.

[0052] In addition, such as Figure 5 As shown, the alternating TiOx and SiO2 portions have the same height, which can range from 150 to 600 nanometers.

[0053] This parameter design has a crucial impact on the optical properties and structural stability of metasurfaces.

[0054] From an optical perspective, this height range effectively matches the wavelengths of light in the visible to near-infrared band (approximately 400-2000 nm). When light is incident on the metasurface, the periodic structure formed by alternating TiOx and SiO2 produces light scattering and interference effects, and the height of 150-600 nm provides sufficient optical path difference, allowing the metasurface to effectively control the phase, amplitude, and other characteristics of the incident light (e.g., achieving beam deflection at specific angles, wavefront shaping, etc.). Simultaneously, the volume ratio of the two materials within this height range can be flexibly controlled by adjusting the width ratio, thereby optimizing the equivalent refractive index and optical response characteristics of the metasurface.

[0055] From a structural perspective, this height range balances the feasibility of nanofabrication with structural stability. On the one hand, heights above 150 nanometers are relatively easy to achieve using existing photolithography, etching, and atomic layer deposition filling processes, avoiding increased processing difficulty and performance fluctuations caused by excessively thin structures. On the other hand, heights below 600 nanometers effectively prevent mechanical stability issues caused by excessively tall structures (such as cracking and detachment due to material stress accumulation), ensuring the reliability of the metasurface during long-term use.

[0056] In practical applications, when it is necessary to modulate short-wavelength light (such as blue light and ultraviolet light), a lower height of 150-300 nanometers can be selected to reduce the transmission loss of light in the material; while for long-wavelength light (such as near-infrared light) or scenarios that require stronger light field interaction, a higher height of 300-600 nanometers can be used to enhance the metasurface's ability to control light.

[0057] Figure 6 A schematic diagram of a metasurface functional layer according to yet another embodiment of this disclosure is shown.

[0058] Figure 6The illustrated metasurface functional layer embodiment and Figure 5 The core difference lies in the morphology of the TiOx filler. Figure 6 In the structure, TiOx not only fills the gaps in the SiO2 framework, but also extends further and completely covers the top of the SiO2 portion, ultimately forming a continuous and flat surface.

[0059] Specifically, Figure 5 The combination of TiOx and SiO2 tends to be more of a "gap-filling, coplanar, flush" (i.e., the top heights of the two materials are the same, but they maintain their respective structural boundaries), while Figure 6 By increasing the amount of TiOx deposited, it continues to grow upwards after filling the gaps, completely covering the protruding parts of SiO2, and ultimately eliminating the surface steps between the two materials.

[0060] The advantage of this design is that: Optical performance optimization: The planar surface reduces the scattering loss of light during propagation caused by the unevenness of the interface, which is especially beneficial for optical paths that require low-loss transmission (such as laser beam modulation and precision imaging). Enhanced structural integrity: The TiOx capping layer "wraps" the dispersed SiO2 structure into a whole, improving the mechanical strength of the metasurface functional layer and reducing the risk of damage to local structures caused by external friction or stress. Improved compatibility: The flat surface makes it easier to bond and integrate with other optical components (such as filters and anti-reflective layers), reducing bonding bubbles or optical interference caused by uneven interfaces.

[0061] This "fill and full coverage" design, while retaining the high refractive index modulation capability of TiOx and the low refractive index support of SiO2, further enhances the stability and integration of the device through planarization, making it suitable for scenarios with higher requirements for surface flatness and optical transmission efficiency (such as micro optical sensors, high-precision waveguide devices, etc.).

[0062] Exemplary steps for forming an optical device according to one embodiment of this disclosure may be as follows.

[0063] 1. Filter pretreatment Material preparation: Select resin-based filters that have already been coated (such as the first coating layer 121 and the second coating layer 123), with standard sizes such as A4 or 137×110mm.

[0064] Punching process: Using precision molds or laser cutting technology, the entire resin filter is punched into a round wafer (such as an 8-inch wafer) to meet the processing requirements of semiconductor process equipment.

[0065] 2. Temporary bonding to wafer carrier Bonding material selection: Use temporary adhesives that can be debonded by ultraviolet light (UV) (such as 3M's UV peelable adhesive), which are characterized by high adhesion before UV irradiation and a sharp decrease in adhesion after irradiation, making subsequent separation easier.

[0066] Bonding process: UV adhesive is dropped onto the surface of a resin filter or temporary wafer carrier.

[0067] Align the resin filter with the temporary wafer carrier.

[0068] The temporary adhesive is evenly distributed and cured through hot pressing or vacuum lamination processes, ensuring a tight bond between the two.

[0069] The bonding process requires temperature control of ≤100℃ to avoid deformation of the resin substrate due to high temperature.

[0070] 3. Metasurface functional layer processing 3.1 Low-temperature SiO2 deposition A SiO2 layer with a thickness of 150-600 nm (depending on metasurface design requirements) is deposited on the surface of the resin filter using low-temperature processes such as plasma-enhanced chemical vapor deposition (PECVD) or electron beam evaporation (≤100℃).

[0071] 3.2 Photolithography and Etching of SiO2 Structures Photoresist coating: Photoresist (such as AZ series photoresist) is spin-coated onto the SiO2 layer and the solvent is removed by soft baking.

[0072] Exposure and Development: Using a metasurface patterned mask, periodic hole, groove and other structural patterns are defined by ultraviolet lithography or electron beam lithography, and then the unwanted photoresist areas are removed by development.

[0073] Etching process: Reactive ion etching (RIE) or inductively coupled plasma etching (ICP) is used to transfer the photolithographic pattern to the SiO2 layer to form an alternating SiO2 framework structure.

[0074] 3.3 Low-temperature ALD deposition of TiOx Equipment and precursors: Atomic layer deposition (ALD) equipment was used, with titanium tetrachloride (TiCl4) as the titanium source and ozone (O3) or water (H2O) as the oxygen source.

[0075] Deposition process: TiOx was deposited layer by layer in the gaps and on the surface of the SiO2 framework by alternately introducing TiCl4 and O3 / H2O, while controlling the temperature to ≤100℃ to avoid damage to the resin substrate.

[0076] By adjusting the number of ALD cycles, ensure that TiOx completely fills the gaps and covers the top of the SiO2 framework (e.g., Figure 6 The planar structure shown.

[0077] 3.4 TiOx Foldback Global planarization is achieved by using chemical mechanical polishing (CMP) or reactive ion etching (RIE) to control the etching rate and ensure the uniformity of TiOx layer thickness, thereby making the TiOx and SiO2 surfaces flat and forming a unified planar structure.

[0078] 3.5 Anti-reflective coating Material selection: Deposit low refractive index materials (such as MgF2, SiO2, etc.) on the surface of the metasurface functional layer (TiOx / SiO2) as an antireflection layer to reduce light reflection loss.

[0079] Process control: The thickness of the anti-reflection layer is precisely controlled through physical vapor deposition (PVD) or ALD processes to achieve destructive interference and reduce reflectivity.

[0080] 4. Temporary bond unbonding UV irradiation: Place the component under a UV lamp to irradiate it, causing the temporary adhesive to lose its stickiness.

[0081] Separation process: Using mechanical force or vacuum adsorption, the resin filter is smoothly separated from the wafer carrier, preserving the complete metasurface functional layer.

[0082] During the fabrication of optical devices, the temperature is kept below 100℃ throughout the process to prevent the resin substrate from deforming or delaminating due to high temperatures. The conformal properties of ALD are utilized to ensure that TiOx can uniformly fill the gaps between SiO2 with a high aspect ratio. TiOx is etched back to achieve planarization of the metasurface functional layer and improve optical performance. UV-debonding adhesive is selected to balance bonding strength and ease of separation, while protecting the fragile resin substrate.

[0083] Specifically, the temporary bonding and debonding process used in the above-mentioned optical device formation process aims to provide temporary support for the ultrathin resin filter in order to solve the process adaptability problem caused by its small thickness.

[0084] Specifically, the filter involved in this application is based on a resin substrate and is extremely thin. While this ultra-thin characteristic can meet the requirements for lightweight and miniaturized devices, it will pose challenges in the subsequent processing of metasurface functional layers (such as photolithography, etching, ALD deposition, etc.).

[0085] For example, the ultrathin resin substrate itself lacks rigidity and is prone to bending, wrinkling or even cracking during clamping, transport or processing, which leads to a decrease in the processing accuracy of the metasurface pattern (such as line offset and structural deformation).

[0086] In addition, temperature changes and mechanical stresses during the process (such as plasma impacts during etching) may further exacerbate substrate deformation, affecting the uniformity of the coating layer or the stability of the structural dimensions, ultimately causing the optical performance of the device to deviate from the design target.

[0087] After temporarily bonding an ultrathin resin filter to a wafer carrier using a UV-debonding adhesive, the high rigidity of the wafer effectively supports the resin substrate, ensuring its flatness throughout the process and guaranteeing stable and controllable key process parameters such as photolithography alignment accuracy, etching uniformity, and ALD deposition conformal properties. Following metasurface processing, UV irradiation enables debonding, allowing for non-destructive separation of the resin filter from the wafer carrier. This retains the advantages of the ultrathin substrate while mitigating its inherent defects, ultimately ensuring consistent device fabrication quality and performance.

[0088] The above process can be used to fabricate high-performance optical devices that integrate metasurface functional layers and filters, which are suitable for fields such as miniature cameras, optical communication modules, and AR / VR devices.

[0089] While numerous embodiments of this disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of this disclosure. It should be understood that various alternatives to the embodiments of this disclosure described herein may be employed in the practice of this disclosure. The appended claims are intended to define the scope of this disclosure and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An optical device, characterized in that, include: A filter configured to filter light of a specific wavelength, the filter including at least one filtering working side; and A metasurface functional layer is disposed on at least one filtering working side of the filter or on a surface opposite to the filtering working side, wherein the metasurface functional layer is a TiOx and SiO2 inlaid structure layer.

2. The optical device according to claim 1, characterized in that, Also includes: An antireflection layer is disposed on the surface of the metasurface functional layer opposite to the filter, for reducing reflection when light shines into the optical device.

3. The optical device according to claim 1, characterized in that, The filter includes: Resin substrate; and The first coating layer and the second coating layer are located on opposite sides of the resin substrate. Both the first coating layer and the second coating layer are configured to filter light of a specific wavelength, and the first coating layer and the second coating layer respectively constitute the two filtering working sides of the filter.

4. The optical device according to claim 1, characterized in that, The filter is configured to filter infrared light.

5. The optical device according to claim 1, characterized in that, The TiOx and SiO2 mosaic structure layer is composed of alternating TiOx and SiO2 portions, wherein each TiOx portion and SiO2 portion is in contact with the filter.

6. The optical device according to claim 1, characterized in that, The material of the metasurface functional layer at the edge of the optical device is SiO2.

7. The optical device according to claim 5, characterized in that, The alternating TiOx and SiO2 portions have the same height, ranging from 150 to 600 nm.

8. The optical device according to claim 3, characterized in that, The thickness of the resin substrate is less than 0.21 micrometers.

9. The optical device according to claim 8, characterized in that, The thickness of the resin substrate is 0.11 micrometers.

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