Terahertz electroluminescent device based on metamaterial and application thereof

Abstract

The invention relates to the technical field of terahertz, in particular to a terahertz electroluminescent device based on metamaterials and application thereof. The terahertz electroluminescent device comprises a metamaterial and an electroluminescent material, the metamaterial comprises a substrate and a field enhancement structure arranged on the substrate, the field enhancement structure is provided with a local electric field enhancement position, and the local electric field enhancement position is coated with the electroluminescent material. According to the terahertz electroluminescent device, the electromagnetic enhancement characteristic of the metamaterial and the efficient luminescence characteristic of the electroluminescent material are fully utilized, and electroluminescent of the terahertz frequency band is achieved. In addition, through the tunability of the metamaterial, the device can adapt to different application requirements and has wide applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of terahertz, and particularly to a terahertz field-induced luminescence device based on metamaterials and its applications. Background Art

[0002] The frequency range of terahertz waves is 0.1 - 10 THz, which is located between the microwave and infrared bands in the electromagnetic spectrum. Due to its special position in the electromagnetic spectrum, it can integrate the characteristics of microwave electronics and infrared photonics, and has broad application prospects in fields such as communication transmission technology, ultra-high-speed computing, biomedicine, food safety detection, environmental monitoring, national defense security, and astronomical exploration. However, its development is still restricted by problems such as light source intensity, detection sensitivity, and system complexity.

[0003] Field-induced luminescence is a phenomenon of exciting materials to emit light through an electric field, and is usually used in display detection technology and lighting fields. However, introducing field-induced luminescence technology into the terahertz frequency band faces many challenges, such as the luminescence efficiency of materials, the electric field enhancement mechanism, and the interaction mechanism with terahertz waves. Currently, the research on terahertz field-induced luminescence technology is still in its infancy, mainly focusing on material design and the exploration of luminescence mechanisms. Summary of the Invention

[0004] The present invention provides a terahertz field-induced luminescence device based on metamaterials and its applications, providing new ideas and technical approaches for terahertz spectral analysis and high-sensitivity detection. The present invention enhances the terahertz electric field through the special electromagnetic structure of the metamaterial, thereby achieving an efficient field-induced luminescence effect and high detection sensitivity.

[0005] According to a first aspect of the present invention, there is provided a terahertz field-induced luminescence device, comprising a metamaterial and a field-induced luminescence material, wherein the metamaterial comprises a substrate and a field enhancement structure disposed on the substrate, the field enhancement structure has a local electric field enhancement region, and the field-induced luminescence material is coated on the local electric field enhancement region.

[0006] The terahertz field-emission device of the present invention includes a metamaterial and a field-emission material. The metamaterial is a type of artificial composite material that can achieve electromagnetic functions not possessed by natural materials. The metamaterial exhibits unique electromagnetic response characteristics in the terahertz frequency band and can achieve broadband response or narrowband response according to design requirements. The field-emission material is a material that can produce a luminescence effect under the action of an electric field, usually having the characteristics of high luminescence efficiency, low power consumption, and fast response. Its luminescence mechanism is based on the excitation of electron transitions by an electric field and can achieve luminescence under the action of a strong electric field. The terahertz field-emission device of the present invention combines the metamaterial with the field-emission material, coats the field-emission material at the local electric field enhancement of the field enhancement structure of the metamaterial. The metamaterial interacts with the incident terahertz wave, generates resonance, forms a local electric field enhancement. Under the action of a strong electric field, electrons in the field-emission material placed at the electric field enhancement site obtain energy and accelerate. The accelerated electrons collide with the luminescence center, transfer the energy to the luminescence center, causing it to transition from the ground state to the excited state. The luminescence center in the excited state returns to the ground state through radiative transition, releasing photons, thereby achieving luminescence. The terahertz field-emission device of the present invention improves the optical response efficiency and controllability of the field-emission material to terahertz through the electromagnetic field enhancement effect of the metamaterial. The present invention not only is expected to promote the application of terahertz technology in multiple fields but also will provide new ideas and methods for the deep integration of metamaterials and terahertz technology.

[0007] Further, the field enhancement structure is mainly prepared by micro-nano processing methods, including ultraviolet exposure and etching.

[0008] Further, the field enhancement structure includes single or multiple field enhancement structure units; the local electric field enhancement site is located on the field enhancement structure unit or between two adjacent field enhancement structure units. By designing the field enhancement structure unit as single or multiple and locating the local electric field enhancement site on or between the structure units, the performance, flexibility, and efficiency of the device are significantly improved. This design not only optimizes the electric field distribution, improves the luminescence efficiency, but also reduces the power consumption and enhances the stability and reliability of the device.

[0009] Preferably, the field enhancement structure is formed by arranging multiple field enhancement structure units in an array. When multiple field enhancement structure units are arranged in an array, a synergistic effect can be formed to enhance the overall electromagnetic field enhancement effect and further increase the intensity of the local electric field.

[0010] Further, the constituent materials of the field enhancement structure include metal materials, dielectric materials, or semiconductor materials.

[0011] Metals have excellent electrical conductivity and free electrons, and can generate a significant local surface plasmon resonance (LSPR) effect in the terahertz frequency band. This effect can greatly enhance the local electric field, thereby significantly improving the luminescence efficiency of field-emitting materials. Dielectric materials usually have a high dielectric constant and can achieve effective propagation and reflection of electromagnetic waves in the terahertz frequency band. By designing the structure of dielectric materials, the regulation of electromagnetic fields can be achieved, such as forming a high-Q resonant cavity or waveguide structure to further enhance the electric field. Semiconductor materials have adjustable conductivity and dielectric properties and can exhibit electromagnetic properties between metals and dielectrics at different frequencies. Semiconductor materials can achieve dynamic regulation of the electric field through doping or structural design, and at the same time have good compatibility and processability.

[0012] By changing the structural parameters of the field enhancement structure, the intensity requirement of the device for incident terahertz can be reduced.

[0013] Preferably, the metal material includes one or more of gold, silver, or copper; the dielectric material includes one or more of alumina, silicon nitride, silicon carbide, barium titanate; the semiconductor material includes silicon or gallium arsenide.

[0014] The broadband response characteristics of the metamaterial can excite a series of resonant peaks through the interaction between its structure and incident terahertz, thereby achieving a response to broadband terahertz waves and generating a significant electromagnetic enhancement effect in a relatively wide terahertz frequency band. The broadband response metamaterial structure can simultaneously excite electromagnetic fields at multiple frequencies, thereby enhancing the field strength of terahertz waves. The narrowband response characteristics of the metamaterial are achieved through a precisely designed resonant structure and can generate a high-Q electromagnetic resonance at a specific frequency. The narrowband response metamaterial structure can usually achieve efficient electromagnetic field enhancement at a specific frequency. The terahertz field-emitting device of the present invention can generate a significant electromagnetic enhancement effect in a relatively wide terahertz frequency band through a multi-resonant mode design to achieve broadband response, and achieve efficient electromagnetic field enhancement at a specific frequency through a high-Q resonant structure to achieve narrowband response.

[0015] To achieve broadband response, in some specific embodiments, the field enhancement structure is a grating structure; the grating structure is formed by arranging a plurality of grating structure units in an array; the local electric field enhancement is located between the grating structure units of the grating structure. The grating structure has good response characteristics at the operating frequency and can use its local field enhancement effect to provide a strong electric field.

[0016] Furthermore, the period of the grating structure is 20 - 40 um, the duty cycle is 1:(10 - 20), and the thickness is 80 - 120 nm. By adjusting the period, duty cycle, and thickness of the metal grating, the optimization regulation of the luminescence intensity and luminescence wavelength can be achieved, and the response frequency of the target electromagnetic wave can be precisely adjusted.

[0017] In some specific embodiments, the period of the grating structure is 30 um, the duty cycle is 1:15, and the thickness is 100 nm. The material composition of the grating structure is gold.

[0018] To achieve narrowband response, in some specific embodiments, the field enhancement structure is a bowtie structure; the bowtie structure is formed by arranging multiple bowtie structure units in an array; Preferably, the bowtie structure unit is composed of two trapezoidal structures and a gap structure. The two trapezoidal structures are connected by the gap structure. The gap structure has a gap, and the local electric field enhancement occurs at the gap. Due to the combined action of the tip effect and the gap effect in the bowtie structure, the electric field intensity can reach extremely high levels in these regions, usually several times or even dozens of times higher than the incident electric field intensity. This enhancement effect can greatly improve the luminescence efficiency of the field-emitting material. The electric field enhancement effect at the gap is the most significant, and the electric field will be highly concentrated in the narrow gap. This local electric field enhancement provides an ideal excitation environment for the field-emitting material, resulting in a significant increase in the luminescence efficiency. The bowtie structure can achieve high-Q resonance by optimizing geometric parameters (such as trapezoid size, gap size, etc.). High-Q resonance means that efficient electromagnetic field enhancement can be achieved at a specific frequency, thereby improving the response sensitivity of the device to a specific terahertz frequency. This structure can achieve narrowband response, making the device have higher selectivity and sensitivity at a specific frequency.

[0019] The thickness h of the bowtie structure unit is 150 - 250 nm, and the distance P between two adjacent bowtie structure units is 30 - 50 um; the height of the bowtie structure is on the nanometer scale, which can significantly concentrate the electric field, similar to the role of a "nano antenna", thus generating a high-intensity electric field hot spot at the gap. The wavelength of terahertz waves is usually in the millimeter to sub-millimeter range, and a height of 150 - 250 nm enables the bowtie structure to achieve good electromagnetic coupling and resonance effects in the terahertz frequency band, thereby maximizing the electric field enhancement effect. The distance between adjacent bowtie units is on the micrometer scale, which can form a periodic array. This periodic structure can match the wavelength of the incident terahertz wave, further enhancing the overall electromagnetic response.

[0020] Preferably, the gap structure includes two oppositely arranged strip-shaped bodies that are spaced apart to form the gap; the width w1 of the strip-shaped body is 1-3 μm; the width g of the gap is 1-3 μm, and the length l1 is 20-25 μm; the design of the gap width g = 1-3 μm and the length l1 = 20-25 μm enables the electric field to be highly concentrated at the gap. Such a tiny gap can significantly enhance the electric field, forming a so-called "electric field hot spot", thereby greatly improving the luminescence efficiency of the electroluminescent material. The two oppositely arranged strip-shaped bodies can form a symmetric electric field distribution, further enhancing the electric field strength at the gap. This design is similar to a "nano antenna" and can efficiently capture and enhance the incident terahertz wave.

[0021] Preferably, the upper base length l3 of the trapezoidal structure is 8-12 μm, the lower base length l2 is 20-40 μm, and the height w2 is 12-16 μm. The upper base of the trapezoidal structure is narrower, and the lower base is wider, forming a structure similar to a "cone". This structure can significantly enhance the electric field, especially at the tip and gap of the trapezoid. The tip effect causes the electric field lines to be highly concentrated at the tip, thereby forming a high-intensity local electric field. The design of the height and the lower base width of the trapezoidal structure can form a relatively high electric field gradient. This gradient further enhances the electric field at the trapezoidal tip and the gap, thereby improving the excitation efficiency of the electroluminescent material.

[0022] Furthermore, the electroluminescent material is selected from one or more of II-VI group compounds, quantum dots, small molecule organic electroluminescent materials, or polymer organic electroluminescent materials. These materials can generate photon emission under the action of an electric field, and their emission wavelengths can be regulated by the composition and structure of the materials. By selecting a suitable type of electroluminescent material, a better synergistic effect can be formed with the metamaterial of the present invention, improving the luminescence efficiency of the device, optimizing the emission wavelength, enhancing the tunability, improving the stability, meeting specific application requirements, reducing power consumption, and enhancing the terahertz-photon conversion efficiency.

[0023] Preferably, the II-VI group compounds include zinc sulfide or cadmium sulfide, etc.; the quantum dots include CdSe, CdTe, CdSe / ZnS, or CdZnSe, etc.; the small molecule organic electroluminescent materials include aluminum tris(8-hydroxyquinoline) or iridium complexes, etc.; the polymer organic electroluminescent materials include polyfluorene derivatives or polystyrene, etc.

[0024] Furthermore, the field-induced luminescent material is selected from quantum dots; quantum dots (such as CdSe, CdTe, CdSe / ZnS, etc.) are a type of semiconductor nanomaterials with unique optoelectronic properties, and their size is usually at the nanometer level. Quantum dots have a high quantum yield and can achieve efficient luminescence at a lower excitation energy, thereby improving the overall luminescence efficiency of the device. The luminescence process of quantum dots usually has a fast response time and is suitable for application scenarios that require fast detection and imaging. When the terahertz wave is irradiated onto the broadband metamaterial structure, a strong electric field is generated due to the local field enhancement effect of the metamaterial, and its intensity is significantly enhanced relative to the electric field intensity of the incident terahertz wave. The quantum dots are placed in a local electric field, the quantum dots are ionized, and the electrons jump from the valence band of the quantum dots to the conduction band of the adjacent quantum dots. The electrons and holes generated by multiple ionizations that reach the same quantum dot can form excitons, and the excitons can radiate composite light.

[0025] Preferably, the concentration of the quantum dots is 1-20 mg / ml. A concentration of 1-20 mg / ml can ensure that the quantum dots have sufficient distribution density in the local electric field enhancement region of the metamaterial, thereby maximizing the use of the enhanced electric field to stimulate luminescence. If the concentration is too low, the luminescence intensity may be insufficient; while a high concentration may lead to enhanced interactions between quantum dots, which in turn reduces the luminescence efficiency. The electromagnetic enhancement effect of metamaterials can significantly increase the local electric field intensity, and a quantum dot concentration of 1-20 mg / ml can ensure that these enhanced electric fields are efficiently utilized. Quantum dots are more likely to undergo ionization and electronic transitions under the action of a strong electric field, thereby achieving efficient luminescence.

[0026] More preferably, the concentration of the quantum dots is 1-10 mg / ml, further preferably 1-5 mg / ml, and further preferably 1-2 mg / ml.

[0027] Selection of light response wavelength of electroluminescent device based on metamaterials. For the response of terahertz waves, in the visible light range, the shorter the wavelength, the stronger the terahertz induced electric field required, that is, the weaker the sensitivity to terahertz response. Therefore, combined with the current development of electroluminescent quantum dots, red light with a relatively long wavelength in the visible light range can be selected as the visible light response wavelength of terahertz.

[0028] In some specific embodiments, the quantum dots are CdSe / ZnS quantum dots, which are used to emit visible light under a strong field to achieve visible light response to terahertz.

[0029] Further, the field-emitting material is coated on the local electric field enhancement part of the field enhancement structure by spin coating, sputtering or evaporation. Coating the field-emitting material on the local electric field enhancement part of the metamaterial by spin coating, sputtering or evaporation can achieve precise distribution and uniform coverage of the material, improve the luminescence efficiency, enhance the device performance and stability, and has good process compatibility and repeatability. This technical solution provides reliable technical support for the efficient preparation and performance optimization of terahertz field-emitting devices based on metamaterials, making them have broad application prospects in the fields of terahertz imaging, spectral analysis, biomedical detection and communication.

[0030] Preferably, the field-emitting material is coated on the local electric field enhancement part of the field enhancement structure by spin coating.

[0031] More preferably, for the spin coating, it is first spun at a speed of 500 - 700 r / m for 5 - 15 s to spread out, and then spin coated at a speed of 2000 - 4000 r / m for 30 - 90 s.

[0032] Further, the substrate includes high-purity Si, fused quartz, sapphire, polyimide, Al2O3 or β-type Si3N4. By optimizing the substrate material, the response frequency of the target electromagnetic wave can be precisely adjusted.

[0033] Preferably, the thickness of the substrate is 400 - 600 um.

[0034] According to the second aspect of the present invention, the present invention also provides the application of the above-mentioned terahertz field-emitting device in the fields of terahertz imaging, spectral analysis, biomedical detection and communication.

[0035] Advantages of the present invention: The terahertz field-emitting device based on metamaterials of the present invention makes full use of the electromagnetic enhancement characteristics of metamaterials and the high-efficiency luminescence characteristics of field-emitting materials to achieve field emission in the terahertz band. In addition, through the tunability of metamaterials, the device can adapt to different application requirements and has wide applicability.

[0036] The dynamic mechanism of the terahertz field-emitting device of the present invention comes from the local field enhancement effect generated when the metamaterial structural unit interacts with terahertz, and has the advantages of simple operation, convenient processing, and can be used at room temperature, etc., simplifying the processing complexity and the harshness of working conditions.

[0037] The terahertz field-emitting device of the present invention can achieve broadband or narrowband response to terahertz on demand within the range of 0 - 10 THz by optimizing the structural parameters, including the period size, structural size, and substrate material. Description of the drawings

[0038] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of a terahertz field-induced light-emitting device provided in Embodiment 1 of the present invention.

[0040] Figure 2 It is a three-dimensional structural schematic diagram of a field enhancement structural unit in a terahertz field-induced light-emitting device provided in Embodiment 1 of the present invention.

[0041] Figure 3 It is a schematic diagram of detecting broadband terahertz of the terahertz field-induced light-emitting device in Detection Embodiment 1 of the present invention.

[0042] Figure 4 It is a simulation result diagram of the local electric field enhancement of the broadband metamaterial structural unit when detecting terahertz in the embodiments of the present invention.

[0043] Figure 5 It is a photographed light-emitting photo when detecting broadband terahertz of the terahertz field-induced light-emitting device in Detection Embodiment 1 of the present invention.

[0044] Figure 6 It is a visible light spectrum diagram measured when detecting broadband terahertz of the terahertz field-induced light-emitting device in Detection Embodiment 1 of the present invention.

[0045] Figure 7 It is a schematic structural diagram of a terahertz field-induced light-emitting device provided in Embodiment 2 of the present invention.

[0046] Figure 8 It is a three-dimensional structural schematic diagram of a field enhancement structural unit in a terahertz field-induced light-emitting device provided in Embodiment 2 of the present invention.

[0047] Figure 9 It is a schematic diagram of detecting narrowband terahertz of the terahertz field-induced light-emitting device in Detection Embodiment 2 of the present invention.

[0048] Figure 10 It is a spectrum diagram of transmittance, reflectance and absorbance in the simulation of detecting terahertz at a specific frequency point by the narrowband metamaterial structural unit in Embodiment 2 of the present invention.

[0049] Figure 11 It is a simulation result diagram of the local electric field enhancement when the metamaterial at the 3.6T frequency point in Embodiment 2 of the present invention is irradiated by 3.6T terahertz.

[0050] Figure 12This is a luminescence photograph taken when the narrowband metamaterial-based terahertz field-emission device with a resonant frequency of 3.6T in Embodiment 2 of the present invention is irradiated with 3.6T terahertz.

[0051] Figure 13 This is a visible light spectrogram measured when the broadband terahertz of the terahertz field-emission device of Comparative Example 1 of the present invention is used.

[0052] Reference numerals: 1: substrate; 2: field-emission material; 3: field enhancement structure; 31: field enhancement structure unit; 311: trapezoidal structure; 312: gap structure; 3120: gap. Detailed implementation manners

[0053] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0054] Embodiment 1 This embodiment provides a terahertz field-emission device, as Figure 1 and Figure 2 shown, which includes a metamaterial and a field-emission material 2. The metamaterial includes a substrate 1 and a field enhancement structure 3 provided on the substrate 1. The field enhancement structure 3 is a grating structure formed by arranging a plurality of field enhancement structure units 31 (grating structure units) in an array. The gap formed between the grating structure units is the local electric field enhancement area, and the field-emission material 2 is coated on the local electric field enhancement area by spin coating.

[0055] Among them, a fused silica sheet with a relatively high transmittance and low loss at the working frequency is selected as the substrate 1 of the metamaterial. The thickness of the substrate 1 is 500um; the thickness of the grating structure is 100nm, the period of the grating structure unit is 30um, the constituent material is gold, and the duty cycle is 1:15; the field-emission material 2 is CdSe / ZnS quantum dots, and the quantum dot concentration is 1.5mg / ml.

[0056] The schematic diagram of the working mode of the terahertz field-emission device is as Figure 3 shown. According to requirements, broadband or narrowband response can be achieved. The terahertz field-emission device is placed perpendicular to the polarization direction of the electromagnetic wave electric field. When terahertz irradiates the device surface, an electric field significantly stronger than the incident field by one order of magnitude is generated in the grating structure. The simulation results are as Figure 4As shown, taking the incident electromagnetic wave of 1 THz as an example, the electric resonance structure unit will enhance the electric field by 25 times. The field-induced luminescence material quantum dots are placed at the location where the electric field intensity is enhanced. Under the action of the strong field, ionization occurs. The carriers move from the valence band of one quantum dot to the conduction band of an adjacent quantum dot. Electrons and holes generated by multiple ionizations reaching the same quantum dot can form excitons, and then the excitons can radiatively recombine to emit light. Thus, the optical response to terahertz is achieved. When detecting terahertz, a visible light photo of the emitted light was taken with a CMOS, as Figure 5 shown. It can be seen that obvious luminescence occurs at the slit of the grating structure unit, that is, at the location where the local electric field is enhanced. The wavelength of the emitted light was measured with a spectral analyzer, as Figure 6 shown. It can be seen that in the time-domain spectrogram, terahertz starts to be incident at 10 s and ends at 40 s. During this period, the luminescence wavelength range of the detected quantum dots (620 - 640 nm) has an obvious luminescence signal.

[0057] Embodiment 2 This embodiment provides a terahertz field-induced luminescence device, as Figure 7 and Figure 8 shown. The difference from Embodiment 1 is that: the field enhancement structure 3 in the metamaterial is different. Specifically, the field enhancement structure 3 is a bowtie structure, and the field enhancement structure unit 31 is a bowtie structure unit made of gold, with a thickness h of 200 nm, and the distance P between adjacent two bowtie structure units is 40 μm. A detailed schematic diagram of the field enhancement structure unit 31 is shown as Figure 8 shown. It is composed of two trapezoidal structures 311 and a gap structure 312. The two trapezoidal structures 311 are connected by the gap structure 312. The gap structure 312 includes two oppositely arranged strip-shaped bodies, and the two strip-shaped bodies are spaced apart to form a gap 3120, and the local electric field is enhanced at the gap 3120. The dimensions of the bowtie structure (the width w1 of the strip-shaped body, the gap width g, the gap length l1, the upper base length l3 of the trapezoidal structure, the lower base length l2 of the trapezoidal structure, the height w2 of the trapezoidal structure) are shown in Table 1 below.

[0058] Table 1

[0059] The schematic diagram of the working mode of the device is shown as Figure 9 shown. According to the requirement of achieving a response to 3.6 T, the terahertz field-induced luminescence device is placed perpendicular to the polarization direction of the electromagnetic wave electric field. As Figure 10 shown, in the transmission, reflection, and absorption spectra, there is an obvious resonance valley at 3.6 T. When terahertz irradiates the device surface, an electric field significantly stronger than the incident field is generated within the structure unit. The simulation results are shown as Figure 11As shown, taking the incident electromagnetic wave of 3.6 THz as an example, the electric resonance structure unit will enhance the electric field by 36 times. The electroluminescent material quantum dots are placed at the position where the electric field intensity is enhanced. Under the action of the strong field, ionization occurs. The carriers move from the valence band of one quantum dot to the conduction band of an adjacent quantum dot. The electrons and holes generated by multiple ionizations reaching the same quantum dot can form excitons, and then the excitons can radiatively recombine to emit light. Thus, the optical response to terahertz is achieved. When detecting 3.6 T terahertz, a photo of the emitted visible light was taken with a CMOS as Figure 12 shown. It can be seen that, compared with other surrounding areas, the gap of the bowtie structure is significantly brighter than other areas, indicating that the phenomenon of light emission occurs.

[0060] In the present invention, by changing the parameters of the metamaterial structure unit, including the period size, the size parameters of the structure, the dielectric constant of the substrate, etc., the terahertz wave of a specific frequency can be adjusted.

[0061] Compared with Example 1, after changing to the bowtie structure, it can only respond to terahertz of specific frequency points. The corresponding response frequency points can be designed according to actual needs.

[0062] Comparative Example This comparative example provides a terahertz field-induced luminescence device, which is different from Example 1 in that it only contains metamaterials and does not contain field-induced luminescence materials. When detected with the terahertz field-induced luminescence device, the experimental spectrum is as Figure 13 shown. It can be seen that with the same detection method, no obvious luminescence signal appears in the luminescence range of the quantum dots in the blank sample.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A terahertz field-emission device based on metamaterials, characterized in that, It includes metamaterials and field-emitting materials. The metamaterials include a substrate and a field enhancement structure disposed on the substrate. The field enhancement structure has a local electric field enhancement region, and the field-emitting materials are coated on the local electric field enhancement region.

2. The terahertz field-induced luminescence device according to claim 1, characterized in that, The field enhancement structure includes single or multiple field enhancement structure units; the local electric field enhancement region is located on the field enhancement structure units or between two adjacent field enhancement structure units; Preferably, the field enhancement structure is formed by arranging multiple field enhancement structure units in an array.

3. The terahertz field-induced luminescence device according to claim 1 or 2, characterized in that, The constituent materials of the field enhancement structure include metal materials, dielectric materials or semiconductor materials; Preferably, the metal materials include one or more of gold, silver or copper; the dielectric materials include one or more of aluminum oxide, silicon nitride, silicon carbide, barium titanate; the semiconductor materials include silicon or gallium arsenide.

4. The terahertz field-induced luminescence device according to any one of claims 1-3, characterized in that, The field enhancement structure is a grating structure; the grating structure is formed by arranging multiple grating structure units in an array; the local electric field enhancement region is located between the grating structure units of the grating structure; Preferably, the period of the grating structure is 20 - 40 μm, the duty cycle is 1:(10 - 20), and the thickness is 80 - 120 nm.

5. The terahertz field-induced luminescence device according to any one of claims 1-3, characterized in that, The field enhancement structure is a bowtie structure; the bowtie structure is formed by arranging multiple bowtie structure units in an array; Preferably, the bowtie structure unit is composed of two trapezoidal structures and a gap structure. The two trapezoidal structures are connected by the gap structure. The gap structure has a gap, and the gap is the local electric field enhancement region.

6. The terahertz field-emission device according to claim 5, wherein The thickness h of the bowtie structure unit is 150 - 250 nm, and the distance P between two adjacent bowtie structure units is 30 - 50 μm; Preferably, the gap structure includes two oppositely arranged strip-shaped bodies. The two strip-shaped bodies are spaced apart to form the gap; the width w1 of the strip-shaped body is 1 - 3 μm; the width g of the gap is 1 - 3 μm, and the length l1 is 20 - 25 μm; Preferably, the upper base length l3 of the trapezoidal structure is 8 - 12 μm, the lower base length l2 is 20 - 40 μm, and the height w2 is 12 - 16 μm.

7. The terahertz field-induced light-emitting device according to any one of claims 1-6, characterized in that, The field-emitting materials are selected from one or more of II-VI group compounds, quantum dots, small molecule organic electroluminescent materials or polymer organic electroluminescent materials; Preferably, the II-VI group compounds include zinc sulfide or cadmium sulfide; the quantum dots include CdSe, CdTe, CdSe / ZnS or CdZnSe; the small molecule organic electroluminescent materials include aluminum tris(8-hydroxyquinoline) or iridium complexes; the polymer organic electroluminescent materials include polyfluorene derivatives or polystyrene.

8. The terahertz field-induced light-emitting device according to claim 7, wherein, The field-emitting materials are selected from quantum dots; preferably, the concentration of the quantum dots is 1 - 20 mg / ml.

9. The terahertz field-induced luminescence device according to any one of claims 1-8, characterized in that, The substrate includes high-purity Si, fused quartz, polyimide, Al2O3 or β-type Si3N4; Preferably, the thickness of the substrate is 400 - 600 μm.

10. Application of the terahertz field-emitting device according to any one of claims 1-9 in the fields of terahertz imaging, detection, spectral analysis, biomedical detection and communication.

Images