Wide-spectrum electromagnetic wave modulation method based on silver-based chalcogenide

Abstract

The invention discloses a wide-spectrum electromagnetic wave modulation method based on silver-based chalcogenide, and belongs to the technical field of electromagnetic wave modulation. According to the invention, the abrupt-change modulation of 1GHz-300THz wide-spectrum electromagnetic waves is realized based on the electronic phase change characteristic of the metal insulator under the triggering of the silver-based chalcogenide under the characteristic external field, and the resonant structure design is combined, so that the functions and applications of electromagnetic wave switching, electromagnetic wave intelligent shielding, dynamic information communication encryption, multi-spectrum camouflage and passive electromagnetic wave protection are realized. The main conception is that a silver-based chalcogenide material with an electronic phase change characteristic is introduced as a sensitive medium, and mutation of electromagnetic wave optical characteristics covering microwave, terahertz and infrared frequency bands caused by electronic phase change of the silver-based chalcogenide is triggered by utilizing characteristic temperature, characteristic pressure and characteristic current. According to the invention, the technical barrier of wide spectrum response and multi-mode dynamic modulation is broken through, and the modulation effect can be cooperatively regulated and controlled by the components of the silver-based chalcogenide material and the structure of the resonant array.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave modulation, and particularly relates to a wide-spectrum electromagnetic wave modulation method based on silver chalcogenide compounds. Background Art

[0002] Electromagnetic waves covering the infrared to microwave bands have important application values in the fields of communication, remote sensing, medical treatment, and military affairs. Among them, the infrared band is an important region in the electromagnetic spectrum with wavelengths ranging between visible light and microwaves, with a wavelength span between 0.78 μm and 300 μm. Infrared radiation is essentially electromagnetic waves generated by the thermal motion of objects. All objects with a temperature higher than absolute zero emit infrared radiation, and the radiation intensity is closely related to the object's temperature. The higher the temperature, the stronger the radiation. In addition, infrared waves have good penetration ability and can penetrate some substances that are difficult for visible light to penetrate. Therefore, they have certain application values in the fields of infrared imaging, non-destructive testing, temperature monitoring, etc. [1]. Terahertz waves (THz) are located between infrared and microwaves in the electromagnetic spectrum, with a frequency range of 0.1 THz to 10 THz and a wavelength span between 30 μm and 3 mm. Terahertz waves have a series of special properties such as low photon energy, high penetrability, broadband nature, and high stability. Therefore, they have broad application prospects in the fields of biomedicine, non-destructive testing, high-speed communication, etc. [2-3]. Microwaves are electromagnetic waves in the electromagnetic spectrum with wavelengths ranging between 1 mm and 1 m, and have characteristics such as high frequency, short wavelength, strong penetration ability, and high energy transmission efficiency. These characteristics enable them to exhibit great application values in many fields such as satellite communication, meteorological monitoring, and aviation navigation [4-5].

[0003] With the wide application of electromagnetic wave technology in the fields of communication, sensing, stealth, etc., the demand for dynamic modulation of wide-band electromagnetic waves covering infrared, terahertz waves, and microwaves is becoming increasingly urgent [6-7]. However, there are still significant limitations in the wide-band regulation mechanisms and material systems of existing technologies. Traditional electromagnetic wave modulation devices (ferrite phase shifters, PIN diode circuits, etc.) rely on the linear interaction between electromagnetic fields and the magnetic moments or carrier concentrations of materials, and have problems such as poor material adaptability, single regulation dimension, and high energy consumption [8]. Among them, ferrite devices are large in volume and difficult to miniaturize, and their operating frequency bands are limited by magnetic anisotropy and it is difficult to cover the entire 0.3 - 300 GHz frequency band. While semiconductor material-based electronic control devices (such as gallium nitride high electron mobility transistors) can only achieve amplitude modulation and lack multi-dimensional collaborative control of phase and polarization [9]. Traditional modulation materials (such as VO2, liquid crystals) are difficult to balance the response to wide-band electromagnetic waves and the multi-field regulation ability [10-11], and the design of a single component of the resonant array makes it difficult to optimize the modulation depth and response speed in a coordinated manner. These problems limit the wide promotion of electromagnetic wave modulation technology in practical applications [12-13].

[0004] In summary, there is still a lack in this field of a method for modulating wide-spectrum electromagnetic waves based on novel functional materials. Silver chalcogenides, due to their reversible electronic phase transition characteristics, broadband response (covering infrared to microwave), and multi-physical field sensitive characteristics, have become ideal candidate materials for breaking through the bottlenecks of existing technologies. Through material composition design and multi-field collaborative triggering mechanisms, wide-bandwidth and multi-dimensional intelligent dynamic modulation can be achieved, providing a core solution for the next generation of electromagnetic functional devices.

[0005] 【1】G.Kastberger and R.Stachl,Behavior Research Methods,Instruments,&Computers 35,429(2003).

[0006] 【2】Y.-Q.Wu,M.-Y.Chen,and Z.-J.Dai,Optics&Laser Technology 183,112339(2025).

[0007] 【3】X.Li,J.Li,Y.Li,A.Ozcan,and M.Jarrahi,Light:Science&Applications12,233(2023).

[0008] 【4】S.Chandrasekaran,S.Ramanathan,and T.Basak,AIChE Journal 58,330(2012).

[0009] 【5】J.C.Slater,Reviews of Modern Physics 18,441(1946).

[0010] 【6】H.Kim,C.Kang,D.Jang,Y.Roh,S.H.Lee,J.W.Lee,J.H.Sung,S.K.Lee,and K.-Y.Kim,Light:Science&Applications 13,118(2024).

[0011] 【7】A.Raveendran,M.T.Sebastian,and S.Raman,Journal of ElectronicMaterials 48,2601(2019).

[0012] 【8】F.A.Ghaffar and A.Shamim,IEEE Transactions on Magnetics 51,1(2015).

[0013] 【9】G.J. Deng, W.H. Huang, J.W. Li, T. Ba, L.T. Guo, and Y. Jiang, Review of Scientific Instruments, 88 (2017).

[0014]

[10] Z. Ren, J. Xu, J. Liu, B. Li, C. Zhou, and Z. Sheng, ACS Applied Materials & Interfaces 14, 26923 (2022).

[0015]

[11] Q.-Y. Wen, H.-W. Zhang, Q.-H. Yang, Y.-S. Xie, K. Chen, and Y.-L. Liu, Applied Physics Letters, 97 (2010).

[0016]

[12] Y. Hao, Z. Niu, J. Yang, M. Wang, H. Liu, Y. Qin, W. Su, H. Zhang, C. Zhang, and X. Li, ACS Applied Materials & Interfaces 16, 32249 (2024).

[0017]

[13] P. Zhang, Q. Liang, Q. Zhou, J. Chen, M. Li, Y. Deng, W. Liang, L. Zhang, Q. Zhang, L. Gu, C. Ge, K.-j. Jin, C. Zhang, and G. Yang, Light: Science & Applications 13, 67 (2024). Summary of the Invention

[0018] The present invention provides a method for modulating wide-spectrum electromagnetic waves based on silver chalcogenide compounds. Its main concept lies in: based on the metal-insulator electronic phase transition characteristics of silver chalcogenide compounds triggered by characteristic temperature, pressure, and electric field, realizing a sudden modulation of the transmission and reflection characteristics of wide-spectrum electromagnetic waves covering microwave, terahertz, and infrared frequency bands. Further, through the design of the material components of silver chalcogenide compounds and the combination with the resonant structure design of the device, continuous modulation of the physical field for critically triggering the metal-insulator electronic phase transition of the material can be achieved, and simultaneously, the spectral distribution relationships of the sudden change in the electromagnetic wave transmittance and reflectance, phase delay, and polarization angle triggered by the metal-insulator phase transition can be adjusted. The technology provided by the present invention can realize functions and applications such as electromagnetic wave switches, electromagnetic wave intelligent shielding, dynamic information encryption, multi-spectrum camouflage, and passive electromagnetic wave protection.

[0019] A broadband electromagnetic wave modulation method based on silver chalcogenide, characterized in that it realizes the abrupt modulation of electromagnetic waves in the broadband range of 1 GHz - 300 THz based on the metal-insulator electronic phase transition characteristics of silver chalcogenide triggered by a characteristic external field, combined with the design of a resonant structure, so as to realize functions and applications such as electromagnetic wave switches, electromagnetic wave intelligent shielding, dynamic information communication encryption, multi-spectrum camouflage, and passive electromagnetic wave protection.

[0020] Further, the silver chalcogenide material components are Ag 2-x A x S 1-y B y , where A is a silver-site substitution element, 0 ≤ x ≤ 1, including elements such as Cu, Zn, Ni, Co, and Bi; B is a sulfur-site substitution element, 0 ≤ y ≤ 1, including elements such as Se, Te, F, Cl, and Br; by controlling the components of the silver chalcogenide, continuous regulation of the external field triggering the metal-insulator phase transition can be achieved, including: the characteristic temperature, pressure, electric field, current density, electromagnetic wave frequency, and power density of the metal-insulator phase transition trigger; and at the same time, the spectral distribution relationships of the abrupt change in electromagnetic wave transmittance and reflectance, phase delay, and polarization angle triggered by the metal-insulator phase transition are realized; the characteristic temperature range is 250 - 500 K; the characteristic pressure range is 10 - 200 MPa; the characteristic electric field strength range is 0.1 - 10 kV / cm; the characteristic current density range is 10 6 -10 9 A / cm 2 ; the characteristic electromagnetic wave frequency range is 1 GHz - 300 THz; the electromagnetic wave power density range is 10 -3 -10 3 W / cm 2 ; in a preferred example, the characteristic temperature triggering the metal-insulator phase transition of the prepared Ag2S 0.95 Te 0.05 is 400 K; in another preferred example, the characteristic pressure triggering the metal-insulator phase transition of the prepared Ag2S 0.9 Se 0.1 is 150 MPa.

[0021] Furthermore, the thin film, powder, and bulk material of the silver chalcogenide can be directly used as a modulation material to achieve electromagnetic wave modulation. By designing the material morphology, size, and topography, the critical external field triggered by the metal-insulator phase transition and the relationships between the sudden changes in the electromagnetic wave transmittance and reflectance, phase delay, and spectral distribution of the polarization angle triggered thereby can be regulated. In a preferred example, the thickness of the prepared Ag2S thin film is 5 nm, its phase transition temperature is 450 K, the average transmittance of electromagnetic waves in the range of 0.3 - 1.4 THz at room temperature is approximately 85%, the average transmittance of electromagnetic waves in the range of 0.3 - 1.4 THz at 460 K is approximately 30%, and the modulation depth is approximately 55%. In another preferred example, the thickness of the prepared Ag2S thin film is 100 nm, its phase transition temperature is 450 K, the average transmittance of electromagnetic waves in the range of 0.3 - 1.4 THz at room temperature is approximately 80%, the average transmittance of electromagnetic waves in the range of 0.3 - 1.4 THz at 460 K is approximately 20%, and the modulation depth is approximately 60%.

[0022] Furthermore, the silver chalcogenide can also be fabricated into an array of resonant units to enhance the modulation function for wide-spectrum electromagnetic waves through the design of its shape and size. A single-component geometric gradient array or a multi-component composite array structure is adopted. By adjusting the spatial distribution of the phase transition thresholds between the units, the dynamic response range of the device is extended, and a non-linear response region is established using the sudden change effect of the optical properties before and after the phase transition, enabling a single device to cover the modulation requirements of a wide frequency band. The shapes include rectangle, circle, pentagram, cross, hexagon, circular ring, square, and their combinations. The geometric parameters include width and gap, with the width ranging from 1 - 100 μm and the gap ranging from 10 - 100 μm. In a preferred example, Ag2S 0.9 Cl 0.1 thin film is fabricated into a periodic array of crosses by micro-nano processing technology, with a film thickness of 200 nm, an arm length of 100 μm, a line width of 20 μm, and a spacing of 50 μm. The phase transition of the cross arms is triggered at a characteristic temperature of 383 K. By utilizing the matching relationship between the impedance of the material and the spatial impedance after the phase transition, the coupling response of the resonant unit to electromagnetic waves is enhanced, showing dual-band regulation characteristics. Sudden changes in transmittance occur at 0.5 THz and 1 THz respectively, and the response time is approximately 200 μs. In another preferred example, a double-ring open groove array is formed on a PET substrate using nanoimprint technology, with an outer diameter of the ring of 150 μm, an inner diameter of 120 μm, an opening angle of 10°, a ring spacing of 40 μm, and a line width of 15 μm. Then Ag 1.8 Cu 0.2 S thin film is deposited, and an electric field of 0 - 10 kV / cm is applied to trigger the phase transition of the material, causing a continuous change in the equivalent inductance of the ring, thereby achieving continuous regulation of the phase delay of electromagnetic waves in the range of 0 - π within the band of 200 GHz - 1000 GHz.

[0023] Furthermore, the silver-based chalcogenide can also be used as a functional layer to be compounded with other functional structural layers and resonator unit arrays to achieve specific modulation functions; the silver-based chalcogenide layer serves as an active phase change medium functional layer, forming a vertical or horizontal integrated architecture with passive resonant structures and auxiliary functional layers, and realizing wide-band multi-modal dynamic regulation through electromagnetic coupling, heat conduction coupling, and mechanical stress transfer effects between layers; in a preferred example, Ag2S thin films and graphene are alternately deposited on a quartz substrate to form a superlattice structure, and a square split-ring resonator array is integrated on the top layer. The thickness of the Ag2S thin film is 200 nm, the period is 500 nm, and the opening width is 50 nm. Raising the temperature to 450 K triggers the phase change of Ag2S, and the dielectric constant of the dielectric layer changes. The Fermi level of graphene can be adjusted by applying a bias voltage of 0 - 5 V, thereby realizing the dynamic modulation of the carrier concentration. Under the coupling effect of the resonator and the heterojunction, dual-tunable filtering windows are generated at 0.8 THz and 2.5 THz respectively, with an insertion loss < 0.5 dB and a modulation speed of about 5 μs; in another preferred example, AgS 1-x Se x gradient thin film arrays are prepared, a 5-μm-thick liquid crystal material is spin-coated and ultraviolet cured, and transparent indium tin oxide is deposited as the top electrode. By applying an electric field of 1 - 5 V / cm, the orientation of liquid crystal molecules is regulated, the local birefringence is changed, the polarization extinction ratio in the 3 - 5 μm mid-infrared band is > 20 dB, the spectral modulation depth is about 90%, the response time is 10 μs, and the cooperative modulation of the polarization state and the resonance frequency generates 8 programmable working modes.

[0024] Furthermore, based on the silver-based chalcogenide material, a wide-spectrum electromagnetic wave modulator can be prepared with characteristic critical temperature, critical pressure, critical current, critical electric field, critical electromagnetic wave absorption frequency, and critical electromagnetic wave absorption power triggering; in a preferred example, Ag2S 0.5 Se 0.5 paste is coated on the surface of an electronic device, and its characteristic critical electromagnetic wave absorption power density is 10 W / cm 2 When the incident electromagnetic wave power density exceeds 10 W / cm 2 , the local thermal effect induces a phase change of the material, and the dielectric loss tangent value increases from 0.03 to 1.2, achieving an increase in the absorption rate from 20% to 95% in the 8 - 12 GHz band. The response bandwidth covers the radar guidance frequency band and is suitable for the passive protection of high-power microwave weapons; in another preferred example, Ag 0.9 Cu 0.1 S 0.9 Te 0.1The Ge2Sb2Te5 superstructure is assembled into an array and subjected to dual-parameter regulation through a temperature of 80-120 °C and an electric field of 0-15 kV / cm. The polarization conversion efficiency of 3-5 μm infrared waves is increased from 15% to 90% by phase transition. Therefore, a dynamic polarization vortex beam with a coding capacity of 2 16 can be generated by electric field programming for real-time quantum encryption in laser communication.

[0025] In the present invention, a silver-based chalcogenide material with electron phase transition characteristics is introduced as the sensitive medium of the resonant unit to construct the resonant unit and the resonant array. After applying an external field to trigger its electron phase transition, the response of the terahertz wave optical characteristics undergoes a mutation, thereby realizing multi-dimensional flexible modulation of the amplitude, phase, and polarization state of the wide-band terahertz wave. The technology provided by the present invention is combined with the existing microstructure processing technology and machine learning technology, and the prepared device has potential application value in intelligent electromagnetic shielding, dynamic information encryption, and multi-spectrum camouflage.

[0026] Through extensive and in-depth research, the present invention obtains a method for modulating wide-spectrum electromagnetic waves based on silver-based chalcogenides. The present invention uses a silver-based chalcogenide material with reversible electron phase transition characteristics as a multi-field sensitive medium to realize multi-dimensional collaborative modulation of the amplitude, phase, and polarization state of terahertz waves and the dynamic response of wide-band terahertz waves, and further realizes the functions of intelligent electromagnetic shielding, dynamic information encryption, and multi-spectrum camouflage. Compared with the traditional terahertz wave modulation technology, this method breaks through the difficulties of low modulation efficiency and narrow-band response, and can be independently or collaboratively regulated by multiple fields. Description of the Drawings

[0027] Figure 1 X-ray diffraction pattern of the Ag2S thin film grown on the glass used in the method of the present invention;

[0028] Figure 2 Resistance-temperature curve of the Ag2S thin film grown on the glass used in the method of the present invention;

[0029] Figure 3 Terahertz wave transmission spectra of the Ag2S thin film grown on the glass used in the method of the present invention at different temperatures;

[0030] Figure 4 Resistance-temperature curve of the Ag2S ribbon used in the method of the present invention;

[0031] Figure 5 Resistance-temperature curve of the Ag2S thin film prepared on mica used in the method of the present invention;

[0032] Figure 6 Ag2S deposited on the glass used in the method of the present invention 0.95 Te0.05 Resistance-temperature curve of the thin film;

[0033] Figure 7 It is the schematic diagram of the passive microwave weapon protection proposed by the method of the present invention. Specific implementation manners

[0034] Unless otherwise specified, various raw materials of the present invention can be commercially available or prepared according to conventional methods in the art. Unless otherwise defined or described, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0035] Other aspects of the present invention will be obvious to those skilled in the art from the disclosure herein.

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0037] Testing method: The prepared materials were characterized by X-ray diffraction, CTA, and a transmission terahertz time-domain spectroscopy system. The characterization method was carried out according to the general standards in the art. Example 1: An Ag2S thin film was deposited on glass. The thickness of the prepared Ag2S thin film was 100 nm, and its X-ray diffraction pattern was as Figure 1 shown, and its resistance-temperature curve was as Figure 2 shown. Its phase transition temperature was 450 K, and its terahertz wave transmission spectrum was as Figure 3 shown. The average transmittance of 0.3 - 1.4 THz electromagnetic waves at room temperature was about 80%, and the average transmittance of 0.3 - 1.4 THz electromagnetic waves at 460 K was about 20%, and the modulation depth was about 60%.

[0038] Example 2: Ag2S powder with a particle size of 50 nm was prepared, pressed into a block, and annealed in vacuum to obtain an Ag2S block. After cold rolling, a thin strip with a thickness of 20 μm was obtained. Its resistance-temperature curve was as Figure 4 shown, and the phase transition temperature was 440 K. The thin strip was integrated into an alarm circuit. When the line current exceeded the limit, the generated Joule heat triggered the phase transition, the surface color changed from gray to red, and at the same time, a 2.4 GHz alarm signal was emitted. The response time < 10 ms, and the number of repeated uses > 10 4 times.

[0039] Example 3: An Ag2S thin film was deposited on mica by a hydrothermal method. The thickness of the obtained Ag2S thin film was 150 nm, and its resistance-temperature curve was as Figure 5As shown, its phase transition temperature is 435K. Using the flexibility of mica, it is sewn into a flexible circuit textile fabric. When a specific radar signal is detected, a 3V voltage is applied through the flexible circuit, and the RCS reduction > 20dB. It can be used as a low RCS shielding cover for intelligent radio stealth clothing.

[0040] Example 4: Deposit a 300nm-thick Ag2S film on glass 0.95 Te 0.05 film, and its resistance-temperature curve is as Figure 6 shown. The phase transition temperature is 400K. When irradiated with a laser with a power density greater than 1kW / cm 2 , the phase transition causes the reflectivity in the 400 - 2000nm band to be > 99.9%, the response time < 1ns, and it can be applied to plasma laser protection goggles.

[0041] Example 5: Deposit an Ag2S film on glass. The thickness of the prepared Ag2S film is 5nm, and its phase transition temperature is 450K. The average transmittance of 0.3 - 1.4THz electromagnetic waves at room temperature is about 85%, and the average transmittance of 0.3 - 1.4THz electromagnetic waves at 460K is about 30%, and the modulation depth is about 55%. Use femtosecond laser to trigger local phase transition and record data to generate characteristic patterns in the terahertz band, which can be used for holographic storage media with a storage density of 1TB / cm 3 , and the read-write speed is 10Gbps. Example 6: Coat the surface of an electronic device with an Ag2S 2 Se 0.5 slurry with a characteristic critical electromagnetic wave absorption power density of 10W / cm 0.5 , which can be applied to the passive protection of high-power microwave weapons with a response bandwidth covering the radar guidance frequency band. The schematic diagram is as Figure 7 shown. When the incident electromagnetic wave power density exceeds 10W / cm 2 , the local thermal effect induces the phase transition of the material, and the tangent value of the dielectric loss angle increases from 0.03 to 1.2, achieving an absorption rate increase from 20% to 95% in the 8 - 12GHz band.

[0042] Example 7: The metal-insulator phase transition triggering characteristic pressure of the Ag2S 0.9 Se 0.1 powder prepared by hydrothermal synthesis is 150MPa, and it is pressed into a cross-shaped metasurface array with a period of 50μm. At a pressure of 150MPa, the phase transition of the material causes the transmittance in the 8 - 12μm mid-infrared band to increase by 40%, and the phase delay reaches 180°. By optimizing the cross arm length (20 - 80μm) through finite element simulation, a pressure sensitivity of 0.8% / MPa is achieved, which is suitable for the pressure-optical dual-mode sensor of intelligent skin, and the linearity R 2 > 0.99.

[0043] Example 8: Prepare an Ag2S thin film with a thickness of 5 nm, a phase transition temperature of 450 K, an average transmittance of 0.3 - 1.4 THz electromagnetic waves at room temperature of about 85%, an average transmittance of 0.3 - 1.4 THz electromagnetic waves at 460 K of about 30%, a modulation depth of about 55%, vertically arranged to form a resonant array. When the current density reaches 5×10 7 A / cm 2 a cooperative phase transition occurs, plasma resonance is generated in the 0.3 - 1.4 THz frequency band, the dynamic range is 60 dB, and the power capacity is 1 W / mm 2 , which can be integrated into a waveguide to achieve a tunable attenuator.

[0044] Example 9: Fabricate a cross-shaped periodic array of Ag2S 0.9 Cl 0.1 thin film by micro-nano processing technology, with a film thickness of 200 nm, an arm length of 100 μm, a line width of 20 μm, and a spacing of 50 μm. The phase transition of the cross arm is triggered at a characteristic temperature of 383 K. Utilize the matching relationship between the impedance of the material after phase transition and the space impedance to enhance the coupling response of the resonant unit to electromagnetic waves, showing dual-band regulation characteristics. Abrupt changes in transmittance occur at 0.5 THz and 1 THz respectively, and the response time is about 200 μs. Example 10: Use nanoimprint technology to form a double-ring open groove array on a PET substrate, with an outer diameter of the ring of 150 μm, an inner diameter of 120 μm, an opening angle of 10°, a ring spacing of 40 μm, and a line width of 15 μm. Then deposit an Ag 1.8 Cu 0.2 S thin film, apply an electric field of 0 - 10 kV / cm to trigger the phase transition of the material, causing a continuous change in the equivalent inductance of the ring, thereby realizing continuous regulation of the phase delay of electromagnetic waves in the 200 GHz - 1000 GHz band between 0 and π.

[0045] Example 11: Alternately deposit Ag2S thin film and graphene on a quartz substrate to form a superlattice structure, and integrate a square split-ring resonator array on the top layer. The thickness of the Ag2S thin film is 200 nm, the period is 500 nm, and the opening width is 50 nm. Raise the temperature to 450 K to trigger the phase transition of Ag2S, the dielectric constant of the dielectric layer changes, and the Fermi level of graphene can be adjusted by applying a bias voltage of 0 - 5 V, thereby realizing dynamic modulation of the carrier concentration. Under the coupling effect of the resonant unit and the heterojunction, dual tunable filtering windows are generated at 0.8 THz and 2.5 THz respectively, with an insertion loss <0.5 dB and a modulation speed of about 5 μs.

[0046] Example 12: Prepare AgS 1-x Se xGradient thin film array, spin-coat a 5-μm-thick liquid crystal material and cure it by ultraviolet light, deposit transparent indium tin oxide as the top electrode, control the liquid crystal molecular orientation by applying an electric field of 1-5 V / cm, change the local birefringence, and the polarization extinction ratio in the 3-5-μm mid-infrared band is >20 dB, the spectral modulation depth is about 90%, the response time is 10 μs, and the cooperative modulation of the polarization state and the resonance frequency point generates 8 programmable working modes.

[0047] Example 13: Deposit Ag on a flexible PDMS substrate 0.9 Cu 0.1 S 0.9 Te 0.1 / Ge2Sb2Te5 superstructure and assemble it into an array, perform two-parameter regulation through a temperature of 80-120 °C and an electric field of 0-15 kV / cm, and trigger the polarization conversion efficiency of the 3-5-μm infrared wave to jump from 15% to 90% through phase change. Therefore, a dynamic polarization vortex beam with a coding capacity of 2 can be generated by electric field programming for real-time quantum encryption in laser communication. 16

[0048] Example 14: Use screen printing to coat a slurry with a gradient distribution of Ag 2-x Zn x S(x = 0-0.3) on the armor surface to form a thickness gradient (50-200 μm). When the ambient temperature rises from 300 K to 400 K, phase changes occur successively in different regions, reducing the thermal infrared emissivity in the 8-14-μm band from 0.9 to 0.3 while keeping the radar scattering coefficient in the 3-mm band stable (±0.1 dB), and the temperature control response time <3 ms, enabling multi-spectrum adaptive camouflage.

[0049] Example 15: Construct an Ag 1.9 Ni 0.1 S 0.9 Cl 0.1 / ITO multilayer structure (total thickness 500 nm), generate a photovoltaic effect under 1 kW / m 2 light illumination, and trigger the phase change by superimposing a 1-V voltage. The microwave transmittance switches from 70% to 10%, and the near-infrared reflectance increases to 90%. Combining with an MPPT circuit to achieve self-powered regulation, the response speed <100 ms, suitable for building energy-saving windows and laser protection systems.

[0050] Example 16: Design an Ag 1.8 Bi 0.2 S / carbon fiber composite layered structure, reduce the phase change critical power density to 10 mW / cm 2 . In the range of 2-18 GHz, the microwave absorption bandwidth expands from 4 GHz to 12 GHz (reflectivity < -10 dB) before and after phase change, the thickness is only 1.2 mm, and the areal density <2 kg / m2 , with a temperature resistance of -50 to 150 °C, suitable for airborne radomes.

[0051] Example 17: Prepare an Ag2S microcolumn array (height 3 μm, diameter 2 μm) by laser direct writing, and apply 0.1 THz, 10 W / cm 2 The terahertz wave triggers a phase change to generate a programmable phase distribution. Dynamic holographic display is achieved in the 0.3 - 3 THz frequency band, with a refresh rate of 1 kHz, a spatial resolution of λ / 2, and a penetration depth of up to 20 cm, which can be applied to security inspection imaging systems.

[0052] Example 18: Grow a 50-nm-thick Ag 1.9 Cu 0.1 S 0.9 Te 0.1 thin film on the surface of the optical fiber. When the strain of the optical fiber exceeds 0.2%, the phase change causes the transmission loss at a wavelength of 1550 nm to increase by 20 dB, with a spatial resolution of 1 m, a measurement range of 0 - 5%, and a distributed electromagnetic wave switch can be realized.

[0053] Example 19: Integrate an Ag 1.95 Zn 0.05 S microring resonator (diameter 10 μm) on a silicon-based photonic chip. By thermally tuning (ΔT = 10 K) to change the phase change state, wavelength channel selection at 1550 nm is achieved, with an extinction ratio > 40 dB, crosstalk < -50 dB. Combined with a single-photon detector, a reconfigurable quantum key distribution system is constructed, integrating a quantum communication filtering chip with a bit error rate < 1%.

[0054] Example 20: Coat the interior of the cabin with an Ag2S 0.9 Br 0.1 coating (thickness 1 mm). When encountering an electromagnetic pulse (field strength > 3 kV / m), the phase change of the material increases the shielding effectiveness from 30 dB to 80 dB (1 - 10 GHz), and the response time < 10 ns. Combining with a conductive grid to form a Faraday cage, the function of intelligent electromagnetic wave shielding can be realized.

[0055] Example 21: Prepare an Ag 1.8 Ni 0.2 S / PDMS flexible composite material (Young's modulus 0.1 - 1 MPa) by 3D printing. The mechanical pressure (0.1 - 1 MPa) generated by human movement triggers a local phase change, resulting in a change in the transmission loss of the 2.4 GHz Bluetooth signal, with a sampling rate of up to 100 Hz, and passive motion capture can be realized.

[0056] Example 22: Integrate an Ag2S phase change thin film waveguide (length 5 mm) on a LiNbO3 modulator. Apply a 40 GHz microwave signal (power 20 mW) to trigger non-linear phase change, generate optical carrier sidebands, and achieve 60 GHz millimeter wave generation. The conversion efficiency > 15%, the spurious suppression ratio > 50 dB, suitable for microwave photonic frequency converters in 5G fronthaul networks.

[0057] Example 23: Prepare Ag2S 0.8 Se 0.2 porous thin film (porosity 60%). In the temperature range of 250 - 400 K, the solar absorption ratio increases from 0.2 to 0.8, and the infrared emissivity decreases from 0.9 to 0.4. It can be applied to satellite thermal control coatings for deep space exploration, achieve day-night temperature difference compensation, and the steady-state temperature fluctuation < 10 K.

[0058] Example 24: Prepare an Ag 1.9 Cu 0.1 S thin film with a thickness of 200 nm. Apply an electric field of 5 kV / cm at 300 K, and the material undergoes a metal-insulator phase change, resulting in a sudden drop in the reflectivity in the 3 - 10 THz band from 85% to 12%. By adjusting the Cu doping amount (x = 0.05 - 0.2), the phase change electric field threshold can be linearly adjusted between 2 - 8 kV / cm. After integrating this thin film with interdigital electrodes, the response time < 5 μs, the insertion loss < 0.5 dB, and the isolation > 30 dB, suitable for dynamic filters in 5G millimeter wave communication.

Claims

1. A terahertz wave multi-field modulation method based on silver-based chalcogenide compounds, characterized in that: Based on the metal insulator electronic phase change characteristics of silver-based chalcogenides under the triggering of characteristic external fields, abrupt modulation of electromagnetic waves in a wide spectrum range of 1GHz-300 THz is achieved. Combined with the resonant structure design, electromagnetic wave switching, electromagnetic wave intelligent shielding, dynamic information communication encryption, multi-spectrum camouflage, and passive electromagnetic wave protection functions and applications are realized.

2. The terahertz wave multi-field modulation method based on silver-based chalcogenide compounds according to claim 1, characterized in that: The silver-based chalcogenide material component is Ag 2-x A x S 1-y B y , wherein A is a silver-substituting element, 0≤x≤1, including Cu, Zn, Ni, Co, and Bi; B is a sulfur-substituting element, 0≤y≤1, including Se, Te, F, Cl, and Br; by controlling the composition of the silver-based chalcogenide compound, continuous regulation of the external field triggering the metal-insulator phase change can be achieved, including: the metal-insulator phase change triggering characteristic temperature, pressure, electric field, current density, electromagnetic wave frequency and power density; and at the same time, the sudden change of the transmittance and reflectivity of the electromagnetic wave triggered by the metal-insulator phase change, the phase delay, and the spectrum distribution relationship of the polarization angle are achieved; the characteristic temperature range is 250-500K; the characteristic pressure range is 10-200MPa; the characteristic electric field strength range is 0.1-10kV / cm; the characteristic current density range is 10 6 -10 9 A / cm 2 The characteristic electromagnetic wave frequency range is 3GHz-300 THz; the electromagnetic wave power density range is 10 -3 -10 3 W / cm 2 .

3. The terahertz wave multi-field modulation method based on silver-based chalcogenide compounds according to claim 1, characterized in that: The thin film, powder and bulk material of the silver-based chalcogenide compound are used as modulation materials to realize electromagnetic wave modulation, and the critical external field triggered by the metal insulator phase change and the sudden change of the electromagnetic wave transmittance and reflectivity, phase delay and polarization angle spectrum distribution relationship triggered by it are regulated through the material form, size and morphology design.

4. The terahertz wave multi-field modulation method based on silver-based chalcogenide compounds according to claim 1, characterized in that: The silver-based chalcogenide compound is prepared into an array-type resonance unit, and the modulation function of the wide-spectrum electromagnetic wave is enhanced by designing its shape and size; a single-component geometric gradient array or a multi-component composite array architecture is adopted, and the dynamic response range of the device is expanded by adjusting the spatial distribution of the phase change threshold between units, and the optical property mutation effect before and after the phase change is used to establish a nonlinear response range, so that a single device can cover the modulation requirements of a wide frequency band; the shapes include rectangle, circle, five-pointed star, cross, hexagon, ring, and field; the geometric parameters include width and gap, the width range is 1-100μm, and the gap range is 10-100μm.

5. The terahertz wave multi-field modulation method based on silver-based chalcogenide compounds according to claim 1, characterized in that: The silver-based chalcogenide compound is used as a functional layer to be compounded with other functional structure layers and a resonance unit array to achieve a specific modulation function; the silver-based chalcogenide compound layer is used as an active phase change medium functional layer to form a vertical or horizontal integrated architecture with the passive resonance structure and the auxiliary functional layer, and realizes wide-band multi-modal dynamic regulation through electromagnetic coupling, thermal conduction coupling and mechanical stress transfer effects between layers.

6. The terahertz wave multi-field modulation method based on silver-based chalcogenide compounds according to claim 1, characterized in that: The silver-based chalcogenide compound material can be used to prepare a wide-spectrum electromagnetic wave modulator triggered by characteristic critical temperature, critical pressure, critical current, critical electric field, critical electromagnetic wave absorption frequency, and critical electromagnetic wave absorption power.

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