A terahertz emission device and method based on a chiral two-dimensional perovskite material

Abstract

This invention discloses a terahertz emission device and method based on chiral two-dimensional perovskite material, relating to the field of electromagnetic waves. The device includes: a laser source, a conversion unit, and an emission support; the laser source generates a laser beam; the conversion unit converts the femtosecond laser into terahertz radiation; the emission support is used to place and adjust the conversion unit; the conversion unit includes a chiral two-dimensional organic-inorganic hybrid perovskite layer; the laser beam is incident perpendicularly onto the surface of the chiral two-dimensional organic-inorganic hybrid perovskite layer. This invention adjusts the intensity and polarization of the terahertz radiation by changing the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer, thereby obtaining high-power, polarization- and intensity-tunable broadband terahertz radiation.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic waves, and in particular to a terahertz emitting device and method based on chiral two-dimensional perovskite material. Background Technology

[0002] Terahertz (THz) radiation is a far-infrared electromagnetic wave that lies between traditional electronics and photonics, with frequencies typically defined in the range of 0.1–10 THz. Because its photon energy (approximately 0.5–50 meV) highly overlaps with the characteristic vibrational energy levels of many molecules and crystals, terahertz spectroscopy can sensitively capture information about chemical bonds within matter. Simultaneously, the scattering frequency of free electrons in materials also falls within this frequency band, making terahertz waves a powerful tool for characterizing carrier dynamics. Furthermore, terahertz waves exhibit excellent penetration through various insulating media such as paper, clothing, plastics, ceramics, and semiconductor wafers, offering advantages such as non-contact, rapid, and non-destructive testing. With these unique physical properties, terahertz spectroscopy demonstrates profound application potential and strategic value in diverse fields such as physical characterization, biomedicine, industrial inspection, and security radar.

[0003] However, the widespread adoption of terahertz technology remains limited by the low energy conversion efficiency and sensitivity of current source and detector devices. The output power of mainstream pulsed terahertz sources is generally weak (typically below 1 microwatt), which not only increases equipment costs but also makes signal acquisition more difficult. Traditional generation methods mainly rely on the optical rectification effect of laser-induced nonlinear crystals, but substantial breakthroughs in radiation efficiency per unit thickness are difficult to achieve. In recent years, chiral organic-inorganic hybrid perovskite materials have become an emerging direction in terahertz source research due to their unique chiral optical properties and spin-selective effects. Although studies have demonstrated that these materials can generate terahertz radiation under femtosecond pulses through spin injection or bulk photovoltaic effects, current research focuses primarily on exploring the intrinsic mechanisms of the materials. Systematic designs for measuring their emission directionality, polarization dynamics, and crystal anisotropy remain scarce. In particular, chiral two-dimensional organic-inorganic hybrid perovskites exhibit significant chiral axis and in-plane anisotropy characteristics, and the coupling relationship between their radiation intensity and excitation light polarization and crystal orientation urgently requires in-depth investigation using more sophisticated experimental systems. Summary of the Invention

[0004] The purpose of this invention is to provide a terahertz emission device and method based on chiral two-dimensional perovskite material. By changing the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer, the intensity and polarization of the terahertz radiation can be adjusted, thereby obtaining broadband terahertz radiation with high power, adjustable polarization and intensity.

[0005] To achieve the above objectives, the present invention provides a terahertz emission device based on chiral two-dimensional perovskite material, comprising: a laser source, a conversion unit, and an emission support; The laser source is used to generate a laser beam; The conversion unit is used to convert femtosecond laser into terahertz radiation; The launch bracket is used to house and adjust the conversion unit; The conversion unit includes a chiral two-dimensional organic-inorganic mixed perovskite layer; the laser beam is incident perpendicularly on the surface of the chiral two-dimensional organic-inorganic mixed perovskite layer.

[0006] Preferably, the laser source includes: a femtosecond pulsed laser and a polarization modulator; The femtosecond pulsed laser is used to generate a laser beam; The polarization adjuster is located between the femtosecond pulse laser and the conversion unit, and is used to adjust the polarization state of the laser beam incident on the conversion unit.

[0007] Preferably, the polarization modulator is a waveplate used to adjust the laser beam into polarized light; the polarized light includes linearly polarized light and circularly polarized light.

[0008] Preferably, the launch support includes: a base and a rotating platform; The rotating stage is mounted on the base, and its rotation axis is parallel to or coincides with the incident optical axis of the laser beam. The rotating stage is connected to the conversion unit, which drives the conversion unit to rotate in a plane perpendicular to the incident optical axis.

[0009] Preferably, the chiral two-dimensional organic-inorganic mixed perovskite in the chiral two-dimensional organic-inorganic mixed perovskite layer has the general chemical formula R- / S-(A). n (B) m X y In this context, the chiral organic cation A is a chiral amine molecule, B is a metal cation, and X is a halide anion.

[0010] Preferably, the chiral two-dimensional organic-inorganic mixed perovskite has at least one of R- / S-(MBA)2PbI4, R- / S-(NEA)2PbI4, R- / S-(MBA)2SnI4 and R- / S-(MBA)PbI3, wherein MBA is methylbenzylammonium and NEA is 1-(2-naphthyl)ethylammonium.

[0011] Preferably, the conversion section further includes a protective layer; the protective layer is disposed on the incident and exit surfaces of the chiral two-dimensional organic-inorganic mixed perovskite layer.

[0012] Preferably, the laser beam generated by the femtosecond pulse laser has a wavelength of 350nm-9000nm and a pulse width of 10fs-150fs.

[0013] This invention also provides a terahertz emission method based on chiral two-dimensional perovskite materials, implemented using the aforementioned terahertz emission device based on chiral two-dimensional perovskite materials, comprising the following steps: The conversion unit is mounted on the emission bracket; the conversion unit includes: a chiral two-dimensional organic-inorganic mixed perovskite layer; the surface of the chiral two-dimensional organic-inorganic mixed perovskite layer is perpendicular to the incident laser beam; A femtosecond pulsed laser is activated to generate a laser beam, and the polarization state of the laser beam is changed by adjusting the polarization modulator. A laser beam with adjusted polarization is incident perpendicularly onto a chiral two-dimensional organic-inorganic hybrid perovskite layer, which excites terahertz radiation.

[0014] Preferably, the modulation method of the terahertz radiation further includes: By rotating the emission support, the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer can be changed, thereby adjusting the intensity, polarity, or polarization state of the excited terahertz radiation.

[0015] In summary, the terahertz emission device and method based on chiral two-dimensional perovskite material provided by this invention have the following advantages compared with traditional technologies: using a laser beam generated by a femtosecond pulsed laser as the excitation source, the laser beam is perpendicularly incident on the chiral two-dimensional organic-inorganic hybrid perovskite layer, and terahertz radiation is generated through the bulk photocurrent effect induced by the chiral structure of the chiral two-dimensional organic-inorganic hybrid perovskite. By rotating the angle of the emission support to change the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer, the intensity, polarity, or polarization state of the terahertz radiation is controlled, and efficient terahertz emission under perpendicular incident conditions is achieved.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a terahertz emission device based on chiral two-dimensional perovskite material according to the present invention; Figure 2 This is a flowchart of a terahertz emission method based on chiral two-dimensional perovskite material according to the present invention.

[0018] Figure Labels 11. Base; 12. Rotating stage; 21. Protective layer; 22. Chiral two-dimensional organic-inorganic hybrid perovskite layer; 31. Femtosecond pulsed laser; 32. Polarization modulator. Detailed Implementation

[0019] The technical method of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0020] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0021] Techniques, systems, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the instruction manual.

[0022] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] This invention provides a terahertz emission device based on chiral two-dimensional perovskite material, comprising: a laser source, a conversion unit, and an emission support. The laser source generates a laser beam; the conversion unit converts femtosecond laser light into terahertz radiation; and the emission support is used to place and adjust the conversion unit to change the intensity of the terahertz radiation.

[0025] Specifically, such as Figure 1 As shown, the emission support includes a base 11 and a rotating stage 12. The rotating stage 12 is mounted on the base 11, and its rotation axis is parallel to or coincides with the incident optical axis of the laser beam. The rotating stage 12 is connected to a conversion unit, which drives the conversion unit to rotate in a plane perpendicular to the incident optical axis.

[0026] The conversion section includes a protective layer 21 and a chiral two-dimensional organic-inorganic mixed perovskite layer 22. A laser beam is incident perpendicularly on the surface of the chiral two-dimensional organic-inorganic mixed perovskite layer 22.

[0027] In an exemplary embodiment of the present invention, the rotating stage 12 is a support that can rotate along the vertical axis, with a rotation angle range of 0° to 360°, so as to change the relative angle between the in-plane orientation of the chiral two-dimensional organic-inorganic mixed perovskite layer and the polarization direction of the incident light.

[0028] A protective layer 21 is disposed on the incident and exit surfaces of the chiral two-dimensional organic-inorganic mixed perovskite layer 22, with a thickness of 2nm-5nm. The protective layer provided by this invention can isolate water vapor and improve the effective working life of the emission source.

[0029] The general chemical formula of the chiral two-dimensional organic-inorganic mixed perovskite layer 22 is R- / S-(A). n (B) m X y In this context, the chiral organic cation A is a chiral amine molecule, B is a metal cation, and X is a halide anion.

[0030] In an exemplary embodiment of the present invention, the chiral two-dimensional organic-inorganic mixed perovskite is a non-centrosymmetric crystal material, specifically including but not limited to: R- / S-(MBA)2PbI4, R- / S-(NEA)2PbI4, R- / S-(MBA)2SnI4 and R- / S-(MBA)PbI3 two-dimensional chiral two-dimensional organic-inorganic mixed perovskites and their alloys or mixed halogen compounds, wherein MBA is methylbenzylammonium (C6H5C2H4NH3). + NEA is 1-(2-naphthyl)ethylammonium (C 12 H 14 N + The thickness of the chiral two-dimensional organic-inorganic mixed perovskite layer 22 is 0.1 mm to 2 mm.

[0031] The protective layer 21 is made of at least one of polymethyl methacrylate (PMMA), polytriarylamine (PTAA), aluminum oxide, magnesium oxide, and silicon dioxide.

[0032] In this invention, the conversion unit is connected to the rotating stage 12 of the transmitting bracket. By rotating the rotating stage 12, the in-plane azimuth angle of the chiral two-dimensional organic-inorganic mixed perovskite layer 22 can be changed, thereby adjusting the intensity, polarity, or polarization state of the terahertz radiation.

[0033] The laser source includes a femtosecond pulsed laser 31 and a polarization modulator 32. The femtosecond pulsed laser 31 generates a laser beam. The polarization modulator 32 is disposed between the femtosecond pulsed laser and the conversion unit, and is used to adjust the polarization state of the laser beam incident on the conversion unit, thereby adjusting the polarization and intensity of the terahertz radiation. The polarization modulator 32 is a waveplate, used to adjust the laser beam into linearly polarized or circularly polarized light. The waveplate is a half-waveplate or a quarter-waveplate. The laser beam generated by the femtosecond pulsed laser 31 has a wavelength of 350nm-9000nm and a pulse width of 10fs-150fs.

[0034] When the terahertz emission device based on chiral two-dimensional perovskite material is working, the femtosecond pulse laser 31 is incident perpendicularly from the protective layer 21 onto the chiral two-dimensional organic-inorganic mixed perovskite layer 22 via the polarization modulator 32. Under the coupling effect of the chiral structure and the optical field, ultrafast polarization is generated in the chiral two-dimensional organic-inorganic mixed perovskite crystal, generating terahertz radiation, which is transmitted out through the protective layer 21 of the exit surface of the chiral two-dimensional organic-inorganic mixed perovskite layer 22.

[0035] This invention provides a terahertz emission method based on chiral two-dimensional perovskite materials, implemented using the aforementioned terahertz emission device based on chiral two-dimensional perovskite materials, as described above. Figure 2 As shown, it includes the following steps: S1. The conversion unit is mounted on the emission bracket. The conversion unit includes a chiral two-dimensional organic-inorganic hybrid perovskite layer 22. The surface of the chiral two-dimensional organic-inorganic hybrid perovskite layer 22 is perpendicular to the incident laser beam.

[0036] S2. Start the femtosecond pulse laser 31 to generate a laser beam, and change the polarization state of the laser beam by adjusting the polarization modulator 32.

[0037] S3. The laser beam with adjusted polarization is incident perpendicularly onto the chiral two-dimensional organic-inorganic hybrid perovskite layer 22 to excite terahertz radiation.

[0038] In an exemplary embodiment of the present invention, the modulation method of terahertz radiation further includes: Rotating the emission support changes the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer 22, thereby adjusting the intensity, polarity, or polarization state of the excited terahertz radiation.

[0039] This invention can change the in-plane azimuth angle of a chiral two-dimensional organic-inorganic hybrid perovskite crystal by rotating the emission bracket, causing the terahertz emission amplitude to change periodically with the angle, thus achieving the effect of terahertz modulation. Furthermore, the polarization state of the incident laser can be changed by adjusting the polarizer 32, thereby adjusting the polarization direction of the emitted terahertz radiation.

[0040] In summary, this invention uses a femtosecond pulsed laser 31 as the excitation source and adjusts the intensity and polarization of the generated terahertz by changing the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite crystal and the polarization direction of the laser beam, thereby obtaining high-power, polarization-tunable broadband terahertz radiation.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A terahertz emission device based on chiral two-dimensional perovskite material, characterized in that, include: Laser source, conversion unit, and emission support; The laser source is used to generate a laser beam; The conversion unit is used to convert femtosecond laser into terahertz radiation; The launch bracket is used to house and adjust the conversion unit; The conversion unit includes a chiral two-dimensional organic-inorganic mixed perovskite layer; the laser beam is incident perpendicularly on the surface of the chiral two-dimensional organic-inorganic mixed perovskite layer.

2. The terahertz emission device based on chiral two-dimensional perovskite material according to claim 1, characterized in that, The laser source includes: a femtosecond pulsed laser and a polarization modulator; The femtosecond pulsed laser is used to generate a laser beam; The polarization adjuster is located between the femtosecond pulse laser and the conversion unit, and is used to adjust the polarization state of the laser beam incident on the conversion unit.

3. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 2, characterized in that, The polarization modulator is a waveplate used to adjust the laser beam into polarized light; the polarized light includes linearly polarized light and circularly polarized light.

4. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 1, characterized in that, The launch support includes: a base and a rotating platform; The rotating stage is mounted on the base, and its rotation axis is parallel to or coincides with the incident optical axis of the laser beam. The rotating stage is connected to the conversion unit, which drives the conversion unit to rotate in a plane perpendicular to the incident optical axis.

5. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 1, characterized in that, The general chemical formula of the chiral two-dimensional organic-inorganic mixed perovskite layer is R- / S-(A). n (B) m X y In this context, the chiral organic cation A is a chiral amine molecule, B is a metal cation, and X is a halide anion.

6. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 5, characterized in that, The chiral two-dimensional organic-inorganic mixed perovskite has the chemical formula of at least one of R- / S-(MBA)2PbI4, R- / S-(NEA)2PbI4, R- / S-(MBA)2SnI4 and R- / S-(MBA)PbI3, wherein MBA is methylbenzylammonium and NEA is 1-(2-naphthyl)ethylammonium.

7. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 1, characterized in that, The conversion section further includes a protective layer; the protective layer is disposed on the incident and exit surfaces of the chiral two-dimensional organic-inorganic mixed perovskite layer.

8. A terahertz emission device based on chiral two-dimensional perovskite material according to claim 1, characterized in that, The laser beam generated by the femtosecond pulsed laser has a wavelength of 350nm-9000nm and a pulse width of 10fs-150fs.

9. A terahertz emission method based on chiral two-dimensional perovskite materials, characterized in that, This is achieved using the terahertz emission device based on chiral two-dimensional perovskite material as described in any one of claims 1-8, comprising the following steps: The conversion unit is mounted on the emission bracket; the conversion unit includes: a chiral two-dimensional organic-inorganic mixed perovskite layer; the surface of the chiral two-dimensional organic-inorganic mixed perovskite layer is perpendicular to the incident laser beam; A femtosecond pulsed laser is activated to generate a laser beam, and the polarization state of the laser beam is changed by adjusting the polarization modulator. A laser beam with adjusted polarization is incident perpendicularly onto a chiral two-dimensional organic-inorganic hybrid perovskite layer, which excites terahertz radiation.

10. A terahertz emission method based on chiral two-dimensional perovskite material according to claim 9, characterized in that, The modulation methods for terahertz radiation also include: By rotating the emission support, the in-plane azimuth angle of the chiral two-dimensional organic-inorganic hybrid perovskite layer can be changed, thereby adjusting the intensity, polarity, or polarization state of the excited terahertz radiation.

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