A digitally programmable arrayed spin terahertz source device

Abstract

This invention provides a digitally programmable arrayed spin terahertz source device, relating to the field of electromagnetic wave transmission and control technology. It includes a transmitting device and a control system, which are connected. The control system transmits current to the transmitting device to control the terahertz wave emitted by the device. The transmitting device includes a patterned array composed of several coding units. Each coding unit includes a heterojunction composed of a ferromagnetic layer and a non-ferromagnetic layer. The ferromagnetic layer includes two-dimensional ferromagnetic materials and ferromagnetic metals, while the non-ferromagnetic layer includes topological insulators, topological half-metals, and heavy metals. This invention utilizes topological materials and two-dimensional ferromagnetic materials as the non-ferromagnetic and ferromagnetic layer materials of the transmitting device, respectively, thereby improving the transmission efficiency. The invention electrically connects the terahertz transmitting device and the control system, achieving integrated terahertz wave transmission and control, and reducing terahertz wave transmission loss.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave emission and control technology, and in particular to a digitally programmable arrayed spin terahertz source device. Background Technology

[0002] For terahertz modulation, the most commonly used method closest to our proposed scheme is the digitally encoded metasurface. Its principle is to utilize the abrupt changes in phase and amplitude generated by the electromagnetic field on both sides of the unit structure to control the phase and amplitude distribution of electromagnetic waves in space. Specifically, the operating state of the encoded metasurface unit can be represented by a finite number of binary values, and its unit structure can be composed of 1-bit encoding, 2-bit encoding, or even multi-bit encoding. For the 1-bit encoding structure, two types of units with a phase difference of 180° can represent the digits "0" and "1" respectively. These unit structures, represented by these numbers, are periodically arranged in an M×N structure on a two-dimensional plane, i.e., 2... M×N There are several arrangement methods, each corresponding to a unique coding pattern, to achieve a specific modulation function. However, separating the transmitting module from the control module not only increases the transmission loss of terahertz waves but also limits the control speed.

[0003] Therefore, there is an urgent need in this field for a terahertz wave control technology that can reduce losses and improve control speed and efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a digitally programmable arrayed spin terahertz source device. Emerging materials such as topological materials and two-dimensional ferromagnetic materials are used as the non-ferromagnetic and ferromagnetic layers of the transmitting device, respectively. The transmitting device and the control system are integrated. Instead of controlling electromagnetic waves through metasurfaces, the terahertz waves are controlled by controlling the magnitude and / or polarity of the current on the coding unit. This allows for low-loss and high-speed control of terahertz waves, solving the problems of high transmission loss and low control speed in existing control technologies. It reduces the loss of terahertz waves while improving the control speed.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A digitally programmable arrayed spin terahertz source device, comprising:

[0007] A launching device and a control system; the launching device and the control system are integrated and connected.

[0008] The transmitting device includes a patterned array, which includes a plurality of coding units; the transmitting device is used to transmit terahertz waves, and the coding units include heterojunctions;

[0009] The heterojunction includes a first heterojunction or a second heterojunction; the first heterojunction is composed of ferromagnetic layers and non-ferromagnetic layers from bottom to top; the second heterojunction is composed of non-ferromagnetic layers, ferromagnetic layers and non-ferromagnetic layers from bottom to top; the ferromagnetic layers include two-dimensional ferromagnetic materials and ferromagnetic metals, and the non-ferromagnetic layers include topological insulators, topological half-metals and heavy metals.

[0010] The control system is used to control terahertz waves by controlling the magnitude of the current on the plurality of coding units and / or controlling the change of the polarity of the current on the plurality of coding units.

[0011] Optionally, the two-dimensional ferromagnetic material includes: Fe x One of GeTe2 and CrTe2; because the ferromagnetic and non-ferromagnetic layers are bonded to the adjacent layers through van der Waals forces, two-dimensional ferromagnetic materials can get rid of the limitations of lattice matching and compatibility. Furthermore, two-dimensional ferromagnetic materials can obtain high-quality interfaces with no dangling bonds and atomic-level flatness at the interface, which can significantly reduce interface spin loss. While greatly improving emission efficiency, it can also achieve high mechanical flexibility and integrability of spin terahertz.

[0012] Optionally, the ferromagnetic metal includes one or more of Co, Fe, and Ni.

[0013] Optionally, the topological insulator includes: Bi₂Se₃, Bi₂Te₃, Bi x Sb 1-x , Sb2Te3 and (Bi x Sb 1-x One or more of )2Te3.

[0014] Optionally, the topological semimetal includes: WTe2, WSe2, PtSe2, PtTe2.

[0015] Topological materials have broad application prospects in the field of spin terahertz because of the presence of massless Dirac electronic states, strong spin polarization currents, and large spin Hall angles on their surfaces.

[0016] Optionally, the heavy metal includes one or more of W, Ta, and Pt. Since heavy metals W and Ta have large spin Hall angles and their signs are opposite to those of the topological materials, a three-layer spin terahertz emission structure can be prepared by combining topological materials with two-dimensional ferromagnetic materials, which can greatly improve the emission efficiency of the spin terahertz source.

[0017] Optionally, the control system includes a metal electrode and an FPGA; the metal electrode is connected to the FPGA.

[0018] Optionally, the transmitting device further includes a substrate, the substrate comprising an insulating material and a semiconductor material.

[0019] Optionally, the insulating material includes alumina and glass.

[0020] Optionally, the semiconductor material includes gallium arsenide, lead magnesium niobate-lead titanate, and strontium titanate.

[0021] This invention also provides a method for controlling terahertz waves in a digitally programmable arrayed spin terahertz source device, comprising:

[0022] Control the generation of laser light that illuminates the emitting device;

[0023] The current corresponding to each of the encoding units is generated by control; the current is used as input to the corresponding encoding unit.

[0024] Terahertz waves are modulated by controlling the magnitude of the current and / or by controlling the change in the polarity of the current on each of the coding units.

[0025] Optionally, controlling the generation of laser light irradiating the emitting device includes: controlling a laser emitter to generate laser light irradiating the emitting device.

[0026] Optionally, the laser is a femtosecond laser.

[0027] Optionally, the modulation of the terahertz wave by controlling the magnitude of the current and / or controlling the change in the polarity of the current on each of the encoding units specifically includes:

[0028] The waveform, phase, and amplitude of the terahertz wave are modulated by changing the magnitude of the current input to each of the encoding units and / or changing the polarity of the current in the encoding units. The polarity refers to the direction of current propagation in each of the encoding units.

[0029] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0030] This invention provides a digitally programmable arrayed spin terahertz source device, comprising a transmitting device and a control system. The transmitting device includes a patterned array of several coding units for transmitting terahertz waves. Each coding unit comprises a heterojunction, which consists of a ferromagnetic layer and a non-ferromagnetic layer. The ferromagnetic layer includes two-dimensional ferromagnetic materials and ferromagnetic metals, while the non-ferromagnetic layer includes topological insulators, topological half-metals, and heavy metals. This invention integrates the transmitting device and the control system, achieving integrated terahertz wave transmission and control. This reduces terahertz wave transmission loss and eliminates the need for metasurface manipulation. Instead, the terahertz wave is controlled by adjusting the magnitude and / or polarity of the current in the coding units. This allows for low-loss, high-speed control of the terahertz wave, solving the problems of high transmission loss and low control speed in existing control technologies. Furthermore, this invention utilizes emerging materials such as topological materials and two-dimensional ferromagnetic materials as the non-ferromagnetic and ferromagnetic layer materials of the transmitting device, respectively, improving the transmission efficiency of the transmitting device. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram illustrating the phase modulation of the coding unit composed of the first heterojunction through the spin orbital moment effect of the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the spatial beam manipulation of terahertz waves by means of a coding unit composed of a first heterojunction, as described in this invention.

[0034] Figure 3 This is a schematic diagram illustrating the phase modulation of the coding unit composed of a second heterojunction through the spin orbital moment effect of the present invention.

[0035] Figure 4 This is a schematic diagram illustrating the spatial beam manipulation of terahertz waves by means of a coding unit composed of a second heterojunction, as described in this invention.

[0036] Figure 5 The flowchart of the terahertz wave modulation method provided by the present invention is shown below. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The purpose of this invention is to provide a digitally programmable arrayed spin terahertz source device that can reduce losses and improve control speed.

[0039] For terahertz emission, the most commonly used THz sources closest to this scheme are photoconductive antenna terahertz sources and other spin terahertz sources. The photoconductive antenna terahertz source consists of a semiconductor substrate and electrodes. Its working principle is that an ultrashort laser pulse is focused onto the semiconductor material between the electrodes. If the laser photon energy is greater than the band gap width of the semiconductor substrate, electrons can be excited into the conduction band to form photogenerated carriers. These photogenerated carriers move under the influence of a bias electric field, forming a transiently changing current within the laser penetration depth range, thus radiating terahertz waves. The spin terahertz source is generally composed of a ferromagnetic / non-ferromagnetic heterojunction. Its working principle is that when a femtosecond laser pulse irradiates the ferromagnetic / non-ferromagnetic heterobilayer, an ultrafast spin current is excited in the ferromagnetic layer. When the spin current enters the heavy metal layer, the inverse spin Hall effect converts it into a transient charge current, thereby radiating terahertz waves.

[0040] For terahertz modulation, the most commonly used method closest to our proposed scheme is the digitally encoded metasurface. Its principle is to utilize the abrupt changes in phase and amplitude generated by the electromagnetic field on both sides of the unit structure to control the phase and amplitude distribution of electromagnetic waves in space. Specifically, the operating state of the encoded metasurface unit can be represented by a finite number of binary values, and its unit structure can be composed of 1-bit encoding, 2-bit encoding, or even multi-bit encoding. For the 1-bit encoding structure, two types of units with a phase difference of 180° can represent the digits "0" and "1" respectively. These unit structures, represented by these numbers, are periodically arranged in an M×N structure on a two-dimensional plane, i.e., 2... M×N There are several arrangement methods, each corresponding to a coding pattern, which realizes a modulation function.

[0041] Spin terahertz sources are still in the research stage, and there are still significant shortcomings in mechanism exploration, performance optimization, and integration with terahertz modulation technology, which require further research and exploration.

[0042] For terahertz modulation, firstly, separating the transmitting module from the modulation module will not only increase the transmission loss of electromagnetic waves, but also limit the modulation speed, which is not conducive to the miniaturization and integration of the system; secondly, the current coded metasurface still has limitations, such as fixed patterns, and one set of photomasks is only suitable for one encoding method; FPGA-based coded metasurfaces cannot avoid the huge static loss introduced by directly biasing the "on" state.

[0043] Based on the above analysis of the prior art, the embodiments of the present invention provide the following technical solutions:

[0044] Example 1:

[0045] This embodiment provides a digitally programmable arrayed spin terahertz source device, including:

[0046] A transmitting device and a control system are integrated; the transmitting device and the control system are connected in an integrated manner; the control system is used to control the terahertz wave by controlling the magnitude of the current on the encoding unit and / or controlling the change of the current polarity on the encoding unit. In this embodiment, integration means that the control system including the FPGA and metal electrodes and the transmitting device are set together, and the control system includes the transmitting device, which can control the terahertz wave while transmitting it.

[0047] The control system includes metal electrodes and an FPGA; the metal electrodes are connected to the FPGA, and the FPGA is connected to the transmitting device via the metal electrodes, such as... Figure 1 As shown.

[0048] The transmitting device includes a patterned array, which comprises several coding units; the transmitting device is used to transmit terahertz waves, and the coding units include heterojunctions, such as... Figure 2 As shown;

[0049] The heterojunction includes a first heterojunction or a second heterojunction; the first heterojunction is composed of ferromagnetic layers and non-ferromagnetic layers arranged sequentially from bottom to top; the ferromagnetic layers and non-ferromagnetic layers are integrated and disposed on a substrate, such as... Figure 2 As shown. In this embodiment, the ferromagnetic layer and the non-ferromagnetic layer in the first heterojunction are grown on the substrate in the order of non-ferromagnetic layer to ferromagnetic layer. In this embodiment, the spin Hall angle of the non-ferromagnetic layer has the opposite sign.

[0050] The second heterojunction consists of a non-ferromagnetic layer, a ferromagnetic layer, and a non-ferromagnetic layer, arranged sequentially from bottom to top. These layers are integrated on a substrate. Figure 3 and Figure 4 As shown. In this embodiment, the ferromagnetic layer and the non-ferromagnetic layer in the second heterojunction are grown on the substrate in the order of non-ferromagnetic layer, ferromagnetic layer and non-ferromagnetic layer.

[0051] The ferromagnetic layer includes two-dimensional ferromagnetic materials and ferromagnetic metals, while the non-ferromagnetic layer includes topological insulators, topological half-metals, and heavy metals. In this embodiment, the constituent materials of the ferromagnetic and non-ferromagnetic layers include those used in existing terahertz wave emission technologies and metasurface manipulation technologies.

[0052] Two-dimensional ferromagnetic materials include: Fe x One of GeTe2 and CrTe2; as the principle of spin terahertz emission shows, selecting non-ferromagnetic materials with large spin Hall angles and ferromagnetic materials with high spin polarizability is beneficial to improving terahertz emission efficiency. Common ferromagnetic metals and their alloys have been widely used as ferromagnetic layer materials in the development of spin terahertz sources; because the ferromagnetic and non-ferromagnetic layers are bonded to adjacent layers through van der Waals forces, two-dimensional ferromagnetic materials can overcome the limitations of lattice matching and compatibility, and can obtain high-quality interfaces with no dangling bonds and atomic-level flatness at the interface, which can significantly reduce interface spin loss. While greatly improving emission efficiency, it can also achieve high mechanical flexibility and integrability of spin terahertz.

[0053] Ferromagnetic metals include one or more of Co, Fe, and Ni. In this embodiment, ferromagnetic metals also include Co, Fe, and Ni, and their alloys.

[0054] Topological insulators include: Bi₂Se₃, Bi₂Te₃, Bi x Sb 1-x , Sb2Te3 and (Bi x Sb 1-x One or more of Bi₂Se₃, Bi₂Te₃, and Bi₂Te₃ are included. In this embodiment, the topological insulator includes Bi₂Se₃, Bi₂Te₃, and Bi₂Te₃. x Sb 1-x , Sb2Te3 and (Bi x Sb 1-x )2Te3 and their alloys.

[0055] Topological semimetals include: WTe2, WSe2, PtSe2, and PtTe2.

[0056] Topological materials have broad application prospects in the field of spin terahertz because of the presence of massless Dirac electronic states, strong spin polarization currents, and large spin Hall angles on their surfaces.

[0057] The heavy metals include one or more of W, Ta, and Pt. Because W and Ta have large spin Hall angles with signs opposite to those of the topological materials, a three-layer spin terahertz emission structure can be fabricated by combining topological materials with two-dimensional ferromagnetic materials, significantly improving the emission efficiency of the spin terahertz source. In this embodiment, the heavy metals include W, Ta, and Pt, as well as their alloys.

[0058] The substrate comprises insulating and semiconductor materials. Insulating materials include alumina and glass. Semiconductor materials include gallium arsenide, lead magnesium niobate-lead titanate, and strontium titanate.

[0059] The digitally programmable arrayed spin terahertz source device provided in this embodiment has the following main technical principles and improvements:

[0060] This embodiment uses topological materials, such as topological insulators (Bi2Se3, Bi2Te3, Bi...). x Sb 1-x Sb2Te3, (Bi x Sb 1-x Two-dimensional ferromagnetic materials (Fe2Te3 and its alloys), topological half-metals (WTe2, WSe2, PtSe2, PtTe2), and heavy metals with large spin Hall angles (W, Ta, Pt, etc.) are used as non-ferromagnetic layer materials. x Spin terahertz sources with bilayer or trilayer heterostructures can be prepared using ferromagnetic metals (GeTe2, CrTe2) and ferromagnetic metals (Co, Fe, Ni, etc. and their alloys) as ferromagnetic layer materials.

[0061] As can be seen from the principle of spin terahertz emission, selecting non-ferromagnetic materials with large spin Hall angles and ferromagnetic materials with high spin polarization is beneficial to improving terahertz emission efficiency. Common ferromagnetic metals and their alloys have been widely used as ferromagnetic layer materials in the development of spin terahertz sources. Two-dimensional ferromagnetic materials, due to their weaker van der Waals interactions with adjacent layers, can overcome the limitations of lattice matching and compatibility. Furthermore, they can achieve high-quality interfaces with no dangling bonds and atomic-level flatness, potentially significantly reducing interface spin loss. This can greatly improve emission efficiency while achieving high mechanical flexibility and integrability in spin terahertz sources. Topological materials, with their massless Dirac electron states, strong spin polarization currents, and large spin Hall angles, naturally hold great promise in the spin terahertz field. Since heavy metals W and Ta have large spin Hall angles and can also be used as non-ferromagnetic layer materials with opposite signs to topological materials and ferromagnetic materials such as Pt, a three-layer spin terahertz emission structure can be fabricated by combining topological materials with two-dimensional ferromagnetic materials, significantly improving the emission efficiency of spin terahertz sources.

[0062] The digitally programmable arrayed spin terahertz source device proposed in this embodiment has the following technical advantages compared with the prior art:

[0063] 1. Replacing traditional terahertz sources with spin sources has advantages such as low cost, mass production capability, and room temperature operation. In this embodiment, emerging materials such as topological materials and two-dimensional ferromagnetic materials are used as the non-ferromagnetic and ferromagnetic layers of the spin source, respectively, which improves the emission efficiency and integrability of the spin source and promotes the development of on-chip terahertz multifunctional devices.

[0064] 2. The waveform, amplitude, and phase of terahertz waves are ultrafastly controlled using the spin orbital moment effect, and a digital coding method is proposed for the control of unit devices.

[0065] 3. The perfect integration of the terahertz emission module and the control module greatly improves the integration of terahertz devices and systems, and reduces the size of the system.

[0066] 4. By combining a spin terahertz source with a coded phased array, digitally programmable on-chip terahertz ultrafast control is achieved, enabling flexible and controllable beamforming.

[0067] Example 2:

[0068] This embodiment provides a digitally programmable method for controlling an arrayed spin terahertz source device. See [link to relevant documentation]. Figure 5 ,include:

[0069] S1: Control the generation of laser light that illuminates the emitting device.

[0070] In this embodiment, a laser emitter is controlled to generate a laser beam that illuminates the emitting device. The laser is a femtosecond laser.

[0071] S2: Controls the generation of current corresponding to each encoding unit; the current is used to input the corresponding encoding unit.

[0072] S3: Terahertz waves are modulated by controlling the magnitude of the current and / or changing the polarity of the current in each encoding unit. This includes: controlling the phase, amplitude, and waveform of the terahertz waves by changing the magnitude of the current input to each encoding unit and / or changing the polarity of the current in the encoding unit.

[0073] This embodiment employs the spin orbital moment effect as a means of terahertz modulation. The modulation system modulates the terahertz wave by controlling the magnitude and / or changing the polarity of the current in several encoding units, and encodes the radiated terahertz wave, with different codes corresponding to different currents.

[0074] The spin-orbit moment effect, based on spin-orbit coupling, utilizes charge-induced spin current to generate a spin-orbit moment, thereby manipulating the direction of the magnetic moment. According to the principle of spin terahertz emission, the magnitude and direction of the magnetic moment within the ferromagnetic layer directly affect the amplitude and phase of the terahertz radiation. Therefore, theoretically, the spin-orbit moment effect has great potential for achieving on-chip ultrafast terahertz modulation. Since the magnetic moment orientation directly affects the terahertz radiation phase, generally, the magnetic moment direction has two states: parallel and antiparallel. That is, the maximum phase difference of the radiated terahertz is 180°. Therefore, encoding "0" or "1" can be achieved by controlling the flipping of the magnetic moment, thus manipulating the two states with a 180° phase difference of the terahertz.

[0075]

[0076] Where θ is the angle by which the wavefront vector deviates from the z-axis. It is the angle by which the wavefront vector is offset from the x-axis. This represents the waveform of radiation from a single cell, where m represents the x-coordinate of the cell, n represents the y-coordinate of the cell, and N represents the number of cells on each side of the patterned array. It represents the phase shift of a single cell, D is the cell distance, and k is the angular wave number.

[0077] As described in the formula above, the control system transmits current to the encoding units. By controlling the magnitude and / or polarity of the current in several encoding units, the system alters the direction of the magnetic moment in the electromagnetic layer of each encoding unit. Utilizing the spin orbital moment effect to control the magnetic moment, the magnetic moment is flipped, thereby introducing an absolute phase shift in each unit and achieving beamform control. This embodiment overcomes the existing technology's separation of the transmission and control modules, integrating terahertz transmission and control through the spin orbital moment effect and metasurfaces, achieving on-chip ultrafast control.

[0078] This embodiment breaks through the traditional thin-film emission method by performing pattern design on the emission device to achieve multi-dimensional terahertz control.

[0079] First, a reasonable pattern design can effectively control the waveform, amplitude, and phase of the terahertz wave while it is emitted. Second, after designing the pattern, this embodiment can control the magnetic moment reversal of each unit to achieve the purpose of terahertz modulation. More importantly, the placement of each unit is designed at the same time to achieve spatial beam modulation of the terahertz wave.

[0080] For the transmitting device, the control method is mainly based on the spin-orbit moment effect. The system inputs current to the encoding unit and controls the reversal of the magnetic moment in the ferromagnetic layer by controlling the current. By controlling the magnetic moment of the ferromagnetic layer in the transmitting device, the waveform, amplitude, and phase of the radiated terahertz wave are achieved. Specifically, when the current input to the encoding unit is a positive current, as the current amplitude increases, the number of encoding units whose magnetic moments in the ferromagnetic layer reverse positively increases. The number of encoding units that reverse magnetic moments and the number of encoding units that do not reverse magnetic moments both change with the change of the current amplitude. Furthermore, the waveform, amplitude, and phase of the terahertz wave radiated by the encoding units that reverse magnetic moments are different from those radiated by the encoding units that do not reverse magnetic moments. Thus, by controlling the amplitude and transmission direction of the current, the magnetic moment reversal of the encoding unit is controlled, thereby controlling the amplitude and phase of the terahertz wave radiated by different encoding units.

[0081] The input current enters each coding unit of the spin source array (i.e., the patterned array). Each coding unit is a stripe pattern, consisting of a row of long stripes. The input current level minus the accumulated applied level is called the historical level. When the historical level is high, the stripe magnetic moment flips in the positive direction, producing terahertz radiation with an absolute phase of 180 degrees. Conversely, when the historical level is low, the stripe magnetic moment flips in the negative direction, producing terahertz radiation with an absolute phase of 0 degrees.

[0082] Since the stripes within each unit are arranged similarly, they are considered to have no phase difference. As the historical level increases, the number of magnetic moment orientation level polarities in the stripes increases, and the terahertz radiation intensity increases. The input level to each stripe unit is the same, but the current amplitude applied at different times varies, thus achieving amplitude variation.

[0083] The spin source array is composed of multiple stripe units, and each unit has small stripe radiation with different phases. The radiated terahertz waves interfere to form a beam.

[0084] Meanwhile, the phase delay caused by the distance between each pattern will also affect the phase of the emitted terahertz. For arrayed patterns, according to the metasurface control principle, each emitting unit emits terahertz with different phases due to the different directions of the internal magnetic moments. The phases are superimposed to generate a beam, thereby realizing spatial beam control.

[0085] The following will illustrate the digitally programmable arrayed spin terahertz source device and its control method of this application with specific examples. Specifically, this includes:

[0086] A patterned emission array device was fabricated using micro-nano technology. The device consists of an M×N array, and each coding unit in the array is composed of a two-layer (ferromagnetic / non-ferromagnetic) or three-layer (non-ferromagnetic / ferromagnetic / non-ferromagnetic) structure. Under irradiation by an 800nm ​​or 1560nm femtosecond laser, the device emits broadband terahertz radiation (bandwidth in the range of 0–3THz). Simultaneously, an FPGA inputs appropriate currents (-30mA / cm²) of different amplitudes to each unit device. 2 ~30mA / cm 2 A current is applied to the metal electrodes, which in turn applies the current to each coding unit. The magnitude and / or polarity of the current in several coding units are controlled, and the orientation of the magnetic moment within each unit is controlled using the spin-orbit moment effect, thereby modulating the terahertz phase emitted by each unit. Ultimately, the interference of terahertz waves with different phases achieves beamforming in space. By changing the amplitude and phase of the input current in each unit device, ultrafast modulation of the space beam is achieved, completing the perfect integration of the transmitting and controlling units.

[0087] The desired patterned array is fabricated using micro-nano processes (photolithography, etching, electron beam evaporation, etc.). Terahertz emission experiments are conducted on the array pattern using a terahertz time-domain spectroscopy system to determine device performance. It is then determined whether the terahertz wave generated after laser irradiation meets the control requirements. Spin-orbit moment reversal is performed on each unit using a magneto-optical Kerr system to determine the corresponding reversal current range. FPGA control of each unit is implemented through programming. Finally, based on the terahertz time-domain spectroscopy system, different current magnitudes are input to each unit according to a coded format (e.g., 011000… corresponds to a current square wave amplitude of -A+A+AAAA…), causing each unit to radiate terahertz waves of different phases. An angle-controllable detection system is used to detect the terahertz intensity at various points in space to clarify the beam distribution in space, thereby verifying the ultrafast beam control effect of this embodiment. This method creatively integrates the emission module and the control module to achieve ultrafast digital programmable beam control, which is inexpensive and highly effective.

[0088] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0089] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A digitally programmable arrayed spin terahertz source device, characterized in that, include: A launching device and a control system; the launching device and the control system are integrated and connected. The transmitting device includes a patterned array, which includes a plurality of coding units; the transmitting device is used to transmit terahertz waves, and the coding units include heterojunctions; The heterojunction includes a first heterojunction or a second heterojunction; the first heterojunction is composed of ferromagnetic layers and non-ferromagnetic layers from bottom to top; in the first heterojunction, the ferromagnetic layers and non-ferromagnetic layers are grown on a substrate in the order of non-ferromagnetic layer, ferromagnetic layer; the second heterojunction is composed of non-ferromagnetic layers, ferromagnetic layers and non-ferromagnetic layers from bottom to top; in the second heterojunction, the ferromagnetic layers and non-ferromagnetic layers are grown on a substrate in the order of non-ferromagnetic layer, ferromagnetic layer and non-ferromagnetic layer; the ferromagnetic layers include two-dimensional ferromagnetic materials and ferromagnetic metals, and the non-ferromagnetic layers include topological insulators, topological half-metals and heavy metals; The substrate includes an insulating material and a semiconductor material; The control system includes a metal electrode and an FPGA; the metal electrode is connected to the FPGA, and the FPGA is connected to the transmitting device through the metal electrode. The control system is used to control terahertz waves by controlling the magnitude of the current on the plurality of coding units and / or controlling the change of the polarity of the current on the plurality of coding units.

2. The digitally programmable arrayed spin terahertz source device according to claim 1, characterized in that, The two-dimensional ferromagnetic material includes: Fe x One of GeTe2 and CrTe2; The ferromagnetic metal includes one or more of Co, Fe, and Ni.

3. The digitally programmable arrayed spin terahertz source device according to claim 1, characterized in that, The topological insulators include: Bi₂Se₃, Bi₂Te₃, and Bi₂Se₃. x Sb 1-x , Sb2Te3 and (Bi x Sb 1-x One or more of )2Te3.

4. The digitally programmable arrayed spin terahertz source device according to claim 1, characterized in that, The topological semimetals include: WTe2, WSe2, PtSe2, and PtTe2.

5. The digitally programmable arrayed spin terahertz source device according to claim 1, characterized in that, The heavy metals include one or more of W, Ta, and Pt.

6. A control method, characterized in that, The control method is used to control the digitally programmable arrayed spin terahertz source device according to any one of claims 1-5, including: Control the generation of laser light that illuminates the emitting device; The current corresponding to each of the encoding units is generated by control; the current is used as input to the corresponding encoding unit. Terahertz waves are modulated by controlling the magnitude of the current and / or by controlling the change in the polarity of the current on each of the coding units.

7. The control method according to claim 6, characterized in that, The control of generating laser light that illuminates the emitting device includes: controlling a laser emitter to generate laser light that illuminates the emitting device.

8. The control method according to claim 6, characterized in that, The laser in question is a femtosecond laser.

9. The control method according to claim 6, characterized in that, The method of modulating the terahertz wave by controlling the magnitude of the current and / or controlling the change of the current polarity on each of the encoding units specifically includes: The phase, amplitude, and waveform of the terahertz wave are modulated by changing the magnitude of the current input to each of the encoding units and / or changing the polarity of the current in the encoding units.

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