Porous super-structure plasma sensor, preparation method and application

Abstract

The invention relates to the technical field of surface plasma photonics and micro-nano optical sensing, in particular to a porous super-structure plasma sensor and a preparation method and application thereof.The porous super-structure plasma sensor comprises a substrate, and a first metal layer, a first silicon dioxide layer, a second metal layer and a second silicon dioxide layer are sequentially arranged on the substrate; a plurality of nanopore arrays are arranged on the porous superstructure plasma sensor; and the nanopore array penetrates through the first silicon dioxide layer, the second metal layer and the second silicon dioxide layer. Through the synergistic effect of a metal-medium-metal-medium (such as gold / silicon dioxide / gold / silicon dioxide) multi-layer structure and the periodic nanopore array, strong surface plasmon resonance is excited in a visible light-near infrared band, perfect combination of high absorptivity, high sensitivity and high FOM value is realized, and the sensor can be used for gas concentration change detection, and can be applied to detection of gas concentration changes. The problem that an existing plasmon sensor cannot meet the working requirement of the visible light-near infrared band is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of surface plasmon photonics and micro-nano optical sensing technology, in particular to a porous super-plasmonic sensor, a preparation method and an application. BACKGROUND

[0002] Gas concentration detection plays an indispensable role in many key areas of today's society, with a wide range of applications and great significance, covering environmental monitoring, industrial process control, safety warning, medical diagnosis and many other aspects. In view of the importance and wide application of gas concentration detection in many fields, it is of great practical significance and urgency to develop high-performance and high-reliability gas concentration detection technology. Traditional electrochemical detection methods and chromatographic detection methods can meet the needs of gas concentration detection to a certain extent, but also have some limitations. Electrochemical detection methods usually require electrodes to be in direct contact with the measured gas, which is easily affected by factors such as electrode contamination and poisoning, resulting in decreased detection accuracy and shortened service life. Moreover, its response speed is relatively slow, making it difficult to meet the requirements of real-time monitoring. Although the chromatographic detection method has high detection accuracy and selectivity, it has a large device volume, complex operation, high cost, and long detection period, which is not suitable for application in some occasions with high requirements for real-time and portability. Therefore, it is of great research value to find a new type of gas concentration detection technology.

[0003] Among the many new gas concentration detection technologies, optical sensors have gradually emerged with their unique advantages and shown great application potential. Compared with traditional electrochemical or chromatographic detection methods, optical sensors have many advantages such as non-contact, anti-electromagnetic interference, fast response, etc. Non-contact detection method avoids direct contact between the sensor and the measured gas, reduces the possibility of sensor contamination and damage, and improves the stability and service life of the sensor; the anti-electromagnetic interference capability enables the optical sensor to work normally in a complex electromagnetic environment, unaffected by external electromagnetic signals, ensuring the accuracy of the detection data; the fast response speed can reflect the changes in gas concentration in real time, meeting the requirements of real-time monitoring. Among them, the sensor based on plasmonic effect is an important type of optical sensor. Plasmonic effect refers to a collective oscillation phenomenon of light field and free electrons in metal, including surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). When light is incident on the surface of a metal or metal nanostructure, plasmonic resonance occurs if the frequency of the light matches the collective oscillation frequency of the free electrons in the metal. Under the resonance condition, the electric field intensity on the surface of the metal will be greatly enhanced, and this enhanced electric field is very sensitive to the refractive index changes in the surrounding environment. The sensor based on plasmonic effect utilizes this characteristic to convert small changes in environmental refractive index into significant changes in resonance wavelength or light intensity. By detecting the changes in these optical signals, accurate detection of gas concentration can be achieved, thereby realizing high-sensitivity sensing. Metamaterials, as a kind of artificially designed composite structure, provide new ideas and methods for the development of plasmonic sensors. Metamaterials can produce unique electromagnetic responses that natural materials do not have. Through careful design of its structural parameters, it can realize flexible regulation of light field distribution, absorption spectrum and other characteristics, and can excite plasmonic modes with "perfect absorption" characteristics, i.e. the reflection and transmission of light in a certain waveband are greatly suppressed, and the incident light energy is efficiently localized inside the structure and converted into heat or other forms of energy. This perfect absorption characteristic not only means a great enhancement of light-matter interaction, laying a foundation for high-sensitivity sensing, but also endows the sensor with excellent anti-interference ability due to the relative insensitivity of the signal (absorption peak) to external interference factors such as incident angle and polarization.

[0004] Although the sensors based on plasmonic effects combined with metamaterial design have shown many advantages and great potential in the field of gas concentration detection. However, most of the high-performance plasmonic sensors currently work in the infrared band. Although the infrared band has certain advantages in some specific gas detection applications, it also has some limitations compared with the visible-near infrared band. For example, the cost of light source and detector in the infrared band is relatively high, which limits its popularization in large-scale applications. Moreover, the propagation characteristics of infrared light make its transmission in some complex environments limited, such as being easily affected by water vapor, dust, etc. From the perspective of application demand, the light source cost in the visible-near infrared band is relatively low, and there are a large number of mature and low-cost light source equipment on the market to choose from, such as common laser diodes, light-emitting diodes, etc., which greatly reduces the overall cost of the sensor system and is conducive to large-scale popularization and application. At the same time, the detector technology in this band is also very mature, with high sensitivity, high resolution and fast response, which can accurately detect the change of optical signal and provide guarantee for high-precision detection of the sensor. In addition, the light in the visible-near infrared band has small attenuation when propagating in air, which can realize long-distance transmission. The existing plasmonic sensors cannot meet the working requirements of the visible-near infrared band, which limits its development in some application fields with high requirements for cost, portability and remote monitoring. Therefore, it has important scientific research value and practical application prospect to carry out research on plasmonic sensors in the visible-near infrared band. SUMMARY

[0005] In view of the problem in the prior art that the existing plasmonic sensors cannot meet the working requirements of the visible-near infrared band, the application provides a porous superstructure plasmonic sensor, a preparation method and application.

[0006] To achieve the above object, the following technical scheme is adopted: The application provides a porous superstructure plasmonic sensor, which comprises a substrate, wherein the substrate is sequentially provided with a first metal layer, a first silicon dioxide layer, a second metal layer and a second silicon dioxide layer; a plurality of nano-pore arrays are arranged on the porous superstructure plasmonic sensor; and the nano-pore arrays penetrate through the first silicon dioxide layer, the second metal layer and the second silicon dioxide layer.

[0007] Optionally, the material of the substrate is Cytop, silicon, sapphire or SiC.

[0008] Optionally, the material of the first metal layer is Au or Ag; and the materials of the first metal layer and the second metal layer are the same.

[0009] Optionally, the thickness of the first metal layer is greater than or equal to 50 nm.

[0010] Optionally, the thickness of the first silicon dioxide layer is 80-180 nm.

[0011] Optionally, the thickness of the second metal layer is 100-130 nm.

[0012] Optionally, the thickness of the second silicon dioxide layer is 80-180 nm.

[0013] Optionally, the thickness of the substrate is 1200-1500 nm.

[0014] A preparation method of the porous superstructure plasmonic sensor as described above, comprising: depositing a first metal layer, a first silicon dioxide layer, a second metal layer and a second silicon dioxide layer on the substrate in sequence by using a magnetron sputtering or electron beam evaporation technology to obtain a first combination; preparing a nano-pore array on the first combination by using a focused ion beam etching or nano-imprinting technology to obtain the porous superstructure plasmonic sensor; the nano-pore array penetrates through the first silicon dioxide layer, the second metal layer and the second silicon dioxide layer.

[0015] Application of the porous superstructure plasmonic sensor as described above in gas concentration detection.

[0016] Compared with the prior art, the present application has the following beneficial effects: The application provides a porous super-structured plasmonic sensor, comprising a substrate, a first metal layer, a first silicon dioxide layer, a second metal layer and a second silicon dioxide layer arranged on the substrate in sequence; a plurality of nano-pore arrays are arranged on the porous super-structured plasmonic sensor; the nano-pore arrays penetrate the first silicon dioxide layer, the second metal layer and the second silicon dioxide layer. The substrate mainly plays a mechanical support role, the first metal layer and the second metal layer form a double-layer plasmonic structure, the local surface plasmon resonance is excited through the nano-pore array, and the electric field intensity of the sensor surface is significantly enhanced. The first silicon dioxide layer and the second silicon dioxide layer serve as dielectric layers, and the plasmonic resonance condition can be further optimized by adjusting the thickness and the refractive index of the dielectric layers. In addition, the first silicon dioxide layer and the second silicon dioxide layer can provide insulation and protection for the metal layer, prevent the metal layer from being oxidized or chemically corroded, and improve the long-term stability of the sensor. Meanwhile, the silicon dioxide layer can reduce non-specific adsorption, reduce background noise and improve the signal-to-noise ratio. The introduction of the nano-pore array breaks the continuity of the traditional metal-dielectric interface, forms a periodic nano structure, and the surface plasmon resonance effect is further enhanced under the excitation of incident light, and the local electric field intensity is greatly improved. When a plane light covering the 400-1000 nm wave band is vertically incident on the surface of the sensor, the light will interact with the periodic nano-pore array and the metal-dielectric multilayer film structure, excite surface plasmon polariton and local plasmon resonance, and form significant field enhancement. The porous super-structured plasmonic sensor has the advantages of simple structure, visible light-near infrared wave band, strong absorption peak, high sensitivity, strong anti-interference ability, simple preparation process and low cost. Through strict simulation verification, when the environmental refractive index is 1.00, the absorption rate of the porous super-structured plasmonic sensor is as high as 89.8%, close to perfect absorption, and the light capturing capacity is extremely strong. When the refractive index changes due to the change of the concentration of the environmental gas, the resonance wavelength of the absorption peak will be linearly shifted. The sensitivity of the porous super-structured plasmonic sensor is as high as 155.42 nm / RIU. Meanwhile, the full width at half maximum of the resonance peak of the porous super-structured plasmonic sensor is narrow, and the calculated quality factor is 13.44 RIU - ¹, indicating that the sensor is sensitive to the change of the refractive index and has excellent resolution. The strong absorption peak and the high FOM value jointly ensure the high anti-interference ability and detection reliability of the sensor. The porous super-structured plasmonic sensor realizes the breakthrough of high precision, low cost and strong environmental adaptability in gas concentration detection through the synergistic design of plasmon resonance and nano-pore array, and can be applied to the fields of environmental monitoring, industrial safety and intelligent transportation, and provides key technical support for air pollution prevention and control, safety production and smart city construction, and has significant economic and social benefits.

[0017] The application provides a preparation method of the porous super-structured plasmonic sensor, which comprises the following steps: sequentially depositing a first metal layer, a first silicon dioxide layer, a second metal layer and a second silicon dioxide layer on a substrate by adopting a magnetron sputtering or electron beam evaporation technology to obtain a first combination; and preparing a nano-pore array on the first combination by adopting a focused ion beam etching or nano-imprinting technology to obtain the porous super-structured plasmonic sensor. The thickness and uniformity of the first metal layer, the first silicon dioxide layer, the second metal layer and the second silicon dioxide layer can be accurately controlled by the magnetron sputtering or electron beam evaporation technology, so that the basis for the subsequent penetration of the nano-pore array is provided. The nano-pore array is prepared on the first combination by adopting the focused ion beam etching or nano-imprinting technology, the resonance wavelength range of the sensor is accurately controlled and changed by the size, period and arrangement mode of the nano-pore, so that the resonance wavelength range covers a wide spectral region from visible light to near-infrared, the application of the plasmonic sensor is promoted, the method is simple, the preparation of the plasmonic sensor which can stably work in the visible light-near-infrared band can be realized only by relying on the existing equipment, and the preparation and use costs are low.

[0018] The application of the porous super-structured plasmonic sensor in gas concentration detection. The porous super-structured plasmonic sensor can occur plasmonic resonance in the visible light-near-infrared band, realize the detection of gas concentration, has high detection precision, low detection cost and meets different environmental monitoring and industrial safety requirements. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Fig. 1 is a structural schematic diagram of a porous super-structured plasmonic sensor according to the application; wherein a is an axial side view, and b is a cross-sectional view of one nano-pore array.

[0020] Figure 2 Fig. 5 is a flow schematic diagram of a preparation method of a porous super-structured plasmonic sensor according to the application.

[0021] Figure 3 Fig. 6 is an absorption spectrum scanning diagram of a porous super-structured plasmonic sensor according to the application when the environmental refractive index changes from 1.00 to 1.10.

[0022] Figure 4 Fig. 7 is an absorption spectrum of a porous super-structured plasmonic sensor according to the application when the environmental refractive index is 1.00.

[0023] Figure 5 Fig. 8 is a spectrum diagram of the movement of an absorption peak of a porous super-structured plasmonic sensor prepared according to the embodiment of the application near 678 nm with the change of the refractive index (n=1.00 to 1.10).

[0024] Figure 6The electric field intensity (|E|2) distribution (a) and the magnetic field intensity (|H|2) distribution (b) in the xy cross section of a porous superstructure plasmonic sensor of the present application at a resonance wavelength of 678 nm.

[0025] Figure 7 The electric field intensity (|E|2) distribution (a) and the magnetic field intensity (|H|2) distribution (b) in the xz longitudinal section of a porous superstructure plasmonic sensor of the present application at a resonance wavelength of 678 nm.

[0026] Wherein, 1- second silicon dioxide layer, 2- second metal layer, 3- first silicon dioxide layer, 4- first metal layer, 5- substrate, 6- nanopore array. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0029] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0030] In the description of the embodiments of the present application, it should be noted that, if the orientation or position relationship indicated by the terms "upper", "lower", "horizontal", "inner" and the like is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship when the product of the present application is used, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0031] In addition, if the term "horizontal" appears, it does not mean that the components must be absolutely horizontal, but can be slightly inclined. As "horizontal" merely means that the direction is more horizontal than "vertical", it does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0032] In the description of the embodiments of the application, it should also be noted that, unless otherwise clearly specified and limited, if the terms "arrange", "mount", "connect", "connect" appear, they should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] The application will be further described in detail below in conjunction with specific embodiments, which are an explanation of the application rather than a limitation.

[0034] Referring to Figure 1 The application discloses a kind of porous superstructure plasmonic sensor, including substrate 5, first metal layer 4 is sequentially arranged on the substrate 5, first silicon dioxide layer 3, second metal layer 2 and second silicon dioxide layer 1;Several nanopore arrays 6 are provided on the porous superstructure plasmonic sensor;Nanopore array 6 penetrates first silicon dioxide layer 3, second metal layer 2 and second silicon dioxide layer 1.Preferably, the material of substrate 5 is Cytop, silicon, sapphire or SiC, further preferably Cytop.The material of first metal layer 4 is Au or Ag;The material of first metal layer 4 and second metal layer 2 is identical, further preferably, the material of first metal layer 4 and second metal layer 2 is Au.

[0035] Preferably, the thickness of the first metal layer 4 is greater than or equal to 50 nm, the thickness of the first silicon dioxide layer 3 is 80-180 nm, the thickness of the second metal layer 2 is 100-130 nm, the thickness of the second silicon dioxide layer 1 is 80-180 nm, and the thickness of the substrate 5 is 1200-1500 nm;The array period of the nanopore array 6 is 450 nm, and the two-dimensional square arrangement nanopore array with a pore size of 200 nm;Further preferably, the thickness of the first metal layer 4 is equal to 50 nm, the thickness of the first silicon dioxide layer 3 is 130 nm, the thickness of the second metal layer 2 is 100 nm, the thickness of the second silicon dioxide layer 1 is 130 nm, and the thickness of the substrate 5 is 1200 nm.

[0036] Referring to Figure 2 The application provides a method for preparing the porous superstructure plasmonic sensor as described above, comprising: S1: sequentially depositing a first metal layer 4, a first silicon dioxide layer 3, a second metal layer 2 and a second silicon dioxide layer 1 on the substrate 5 by magnetron sputtering or electron beam evaporation technology to obtain a first combination; S2: preparing a nano-pore array 6 on the first combination by focused ion beam etching or nano-imprinting technology to obtain a porous super-structured plasmonic sensor; the nano-pore array 6 penetrates the first silicon dioxide layer 3, the second metal layer 2 and the second silicon dioxide layer 1.

[0037] The parameter optimization and mode screening of the above-mentioned porous super-structured plasmonic sensor are performed by electromagnetic simulation using finite difference time domain (FDTD) method, and data processing (calculation of absorption rate: A = 1-R-T) is performed by Matlab. The structural geometric parameters (such as the thickness of each layer, the pore radius R, the array period T of the nano-pore array 6, etc.) and the environmental refractive index (n from 1.00 to 1.10) are systematically scanned. By analyzing the absorption spectrum, an excellent mode with high absorption rate in the target waveband and a significant shift in resonance wavelength with the change of refractive index is found and determined.

[0038] Mode characteristic verification: after determining the optimal structural parameters, FDTD simulation is performed under the condition of environmental refractive index n = 1.00 to obtain the accurate absorption spectrum (such as Figure 3 indicated), confirming the existence of the target resonance mode (678 nm mode) and its high intensity.

[0039] Sensing performance quantification: on the optimized structure, a series of fine simulations are performed to gradually increase the environmental refractive index from 1.00 to 1.10, and the absorption spectrum corresponding to each refractive index point is obtained. The wavelength shift (Δλ) of the target resonance peak is extracted, and the sensitivity (S) is calculated by linear fitting. At the same time, the full width at half maximum (FWHM) of the resonance peak at the reference refractive index is extracted, and finally the figure of merit (FOM = S / FWHM) is calculated.

[0040] Field distribution analysis: by FDTD simulation, at the resonance wavelength (678 nm), field monitors are set in the xy plane (parallel to the layered structure, located in the 20 nm silicon dioxide layer above the first metal layer) and the xz plane (longitudinal section through the pore center) to obtain the spatial distribution of electric field and magnetic field, which is used to intuitively reveal the properties and energy localization position of the resonance mode, and verify its plasmonic characteristics.

[0041] The above-mentioned porous super-structured plasmonic sensor is applied in gas concentration detection. The porous super-structured plasmonic sensor can occur plasmonic resonance phenomenon in the visible-near infrared waveband, realize the detection of gas concentration, has high detection precision, low detection cost, and meets different environmental monitoring and industrial safety needs.

[0042] Example 1 A gold layer with a thickness of 50 nm is deposited on the Cytop substrate 5 as the first metal layer 4 by magnetron sputtering or electron beam evaporation in sequence; then a first silicon dioxide layer 3 with a thickness of 130 nm is deposited; then a gold layer with a thickness of 100 nm is deposited as the second metal layer 2; and then a second silicon dioxide layer 1 with a thickness of 130 nm is deposited. Finally, a two-dimensional square array of nanoholes with a period of 450 nm and an aperture of 200 nm is prepared in the upper three layers of the stacked structure by using a focused ion beam etching or nanoimprint technology, thereby obtaining a porous super-structured plasmonic sensor.

[0043] The working principle of the porous super-structured plasmonic sensor is as follows: when a plane light (such as white light) covering a waveband of 400-1000 nm is vertically incident on the surface of the sensor, the light will interact with the periodic nanohole array 6 and the metal-dielectric multilayer film structure, and excite surface plasmon polaritons (SPPs) and localized plasmon resonances. Under specific structural parameters, these effects work together to form a strong resonance absorption at a wavelength of 678 nm.

[0044] Referring to Figures 3 to 5 The absorption spectrum mode characteristics of the porous super-structured plasmonic sensor prepared in this embodiment are verified, and it can be seen that the resonance peak of the porous super-structured plasmonic sensor prepared in this embodiment has a red shift trend with the increase of the refractive index. When the environmental refractive index is 1.00, the resonance mode can be generated at 678 nm, and the intensity is very high, and the absorption rate is close to 90%. When the gas concentration of the environment where the sensor is located changes (for example, specific gas molecules to be measured are adsorbed on the surface or wall of the sensor), the effective refractive index near the surface of the sensor will change slightly (Δn). This change will directly disturb the plasmon resonance condition, causing the center wavelength of the resonance absorption peak to move (Δλ), as shown in Figure 3 and Figure 5 The movement amount of the absorption peak site is monitored by a high-resolution spectrometer, and the change amount of the environmental refractive index is inversely deduced, and then the quantitative detection of the gas concentration is realized.

[0045] The sensing performance of the present application is comprehensively evaluated by FDTD simulation. As shown in Figure 5 Within the refractive index change range (Δn=0.10), the resonance wavelength moves about 15.5 nm, and the linear fitting gives a sensitivity S = 155.42 nm / RIU. At the same time, from the absorption spectrum shown in Figure 4 The full width at half maximum of the resonance peak is about 11.56 nm, so the figure of merit FOM = 155.42 / 11.56≈13.44 RIU -1This high FOM value indicates that the sensor has high sensitivity and sharp resonance peak shape, which is conducive to accurate detection of small wavelength changes, thereby improving the resolution and anti-interference ability of the sensor.

[0046] Referring to Figure 6 , the localization and enhancement effect of the possible quantity around the hole are proved; referring to Figure 7 , the distribution and localization of electromagnetic field in the vertical direction of the multilayer structure; it is explained that the optical energy is highly localized around the silica layer and near the metal-dielectric interface, forming significant field enhancement.

[0047] Example 2 On the Cytop substrate 5, a gold layer with a thickness of 60 nm is deposited as the first metal layer 4 by magnetron sputtering or electron beam evaporation in sequence; then a first silica layer 3 with a thickness of 150 nm is deposited; a gold layer with a thickness of 120 nm is continuously deposited as the second metal layer 2; and a second silica layer 1 with a thickness of 150 nm is deposited. Finally, a two-dimensional square arrangement of nanohole array 6 with a period of 440 nm and a hole diameter of 210 nm is prepared in the upper three layers of the stacked structure by using focused ion beam etching or nanoimprint technology.

[0048] Example 3 On the SiC substrate 5, a Ag layer with a thickness of 70 nm is deposited as the first metal layer 4 by magnetron sputtering or electron beam evaporation in sequence; then a first silica layer 3 with a thickness of 180 nm is deposited; a Ag layer with a thickness of 130 nm is continuously deposited as the second metal layer 2; and a second silica layer 1 with a thickness of 180 nm is deposited. Finally, a two-dimensional square arrangement of nanohole array 6 with a period of 460 nm and a hole diameter of 220 nm is prepared in the upper three layers of the stacked structure by using focused ion beam etching or nanoimprint technology.

[0049] Example 4 On the silicon substrate 5, a gold layer with a thickness of 55 nm is deposited as the first metal layer 4 by magnetron sputtering or electron beam evaporation in sequence; then a first silica layer 3 with a thickness of 80 nm is deposited; a gold layer with a thickness of 100 nm is continuously deposited as the second metal layer 2; and a second silica layer 1 with a thickness of 80 nm is deposited. Finally, a two-dimensional square arrangement of nanohole array 6 with a period of 470 nm and a hole diameter of 230 nm is prepared in the upper three layers of the stacked structure by using focused ion beam etching or nanoimprint technology.

[0050] Example 5 A gold layer with a thickness of 70 nm is deposited as the first metal layer 4 on the Cytop substrate 5 by magnetron sputtering or electron beam evaporation in sequence; then a first silicon dioxide layer 3 with a thickness of 150 nm is deposited; then a gold layer with a thickness of 120 nm is deposited as the second metal layer 2; then a second silicon dioxide layer 1 with a thickness of 150 nm is deposited. Finally, a two-dimensional square array of nanoholes 6 with a period of 450 nm and an aperture of 200 nm is prepared in the upper three layers of the stacked structure by using focused ion beam etching or nanoimprint technology.

[0051] In summary, the present application provides a porous super-structured plasmonic sensor, a preparation method and an application. Through the synergistic effect of the metal-dielectric-metal-dielectric (such as gold / silicon dioxide / gold / silicon dioxide) multilayer structure and the periodic nanohole array 6, strong surface plasmon resonance is excited in the visible-near infrared wave band, realizing the perfect combination of high absorption rate, high sensitivity and high FOM value. At the same time, it has the advantages of low cost, large-scale preparation and long service life. The porous super-structured plasmonic sensor can be used for gas concentration change detection, and its application can cover the fields of environmental monitoring, industrial safety, intelligent transportation, etc., significantly reducing the detection cost and improving the monitoring efficiency, providing key technical support for air pollution prevention and control, safety production and smart city construction, and having great economic and social value.

[0052] The above only describes the preferred embodiments of the present application and does not use any restriction on the technical solutions of the present application. Those skilled in the art should understand that the technical solutions can be modified and replaced in several simple ways without departing from the spirit and principles of the present application, and these modifications and replacements also belong to the protection scope of the claims.

Claims

1. A porous superstructured plasmonic sensor, characterized in that, The porous superstructure plasmonic sensor comprises a substrate (5), a first metal layer (4), a first silicon dioxide layer (3), a second metal layer (2) and a second silicon dioxide layer (1) arranged on the substrate (5) in sequence; a plurality of nano-pore arrays (6) are arranged on the porous superstructure plasmonic sensor; the nano-pore arrays (6) penetrate the first silicon dioxide layer (3), the second metal layer (2) and the second silicon dioxide layer (1).

2. The porous superstructured plasmonic sensor of claim 1, wherein, The material of the substrate (5) is Cytop, silicon, sapphire or SiC.

3. The porous superstructured plasmonic sensor of claim 1, wherein, The material of the first metal layer (4) is Au or Ag; the material of the first metal layer (4) is the same as that of the second metal layer (2).

4. The porous superstructured plasmonic sensor of claim 1, wherein, The thickness of the first metal layer (4) is greater than or equal to 50 nm.

5. The porous superstructured plasmonic sensor of claim 1, wherein, The thickness of the first silicon dioxide layer (3) is 80-180 nm.

6. The porous superstructured plasmonic sensor of claim 1, wherein, The thickness of the second metal layer (2) is 100-130 nm.

7. The porous superstructured plasmonic sensor of claim 1, wherein, The thickness of the second silicon dioxide layer (1) is 80-180 nm.

8. The porous superstructured plasmonic sensor of claim 1, wherein, The thickness of the substrate (5) is 1200-1500 nm.

9. A method of fabricating a porous plasmonic sensor as claimed in any one of claims 1-8, characterized in that, The method comprises the following steps: a first combination is obtained by sequentially depositing the first metal layer (4), the first silicon dioxide layer (3), the second metal layer (2) and the second silicon dioxide layer (1) on the substrate (5) by using a magnetron sputtering or electron beam evaporation technology; a nano-pore array (6) is prepared on the first combination by using a focused ion beam etching or nano-imprinting technology to obtain the porous superstructure plasmonic sensor; the nano-pore array (6) penetrates the first silicon dioxide layer (3), the second metal layer (2) and the second silicon dioxide layer (1).

10. The application of the porous superstructure plasmonic sensor in claim 1-8 in the detection of gas concentration.

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