A superluminescent pulsed system

Abstract

The application provides an ultra-radiation pulse system, and belongs to the technical field of ultra-radiation and pulse source. The system comprises a support layer, zero-refractive-index super-structured material, a plurality of metal columns fixed on the support layer and arranged in a periodic interval, and a plurality of dipole transmitting antennas. The zero-refractive-index super-structured material is used for realizing a zero-refractive-index environment for a radiation frequency of the ultra-radiation pulse system. The dipole transmitting antennas are distributed in corresponding interspaces in the zero-refractive-index super-structured material, used as an emission source of ultra-radiation, used for exciting a radiation field of the ultra-radiation in the ultra-radiation pulse system, and used for generating an ultra-radiation pulse signal. An output end is used for outputting the ultra-radiation pulse signal with as low loss as possible. The application can realize the ultra-radiation with a source number growth of emission rate in quantum theory in a microwave to terahertz frequency band range, and the zero-refractive-index environment releases the limitation of the traditional ultra-radiation on a device size smaller than a wavelength, so that the extended ultra-radiation without a linear dimension limitation is possible.

Description

Technical Field

[0001] The present invention relates to the technical field of superradiance and pulse sources, and in particular to a superradiance pulse system based on a zero-refractive-index metamaterial. Background Art

[0002] Superradiance refers to the phenomenon that N identical atoms couple with each other to produce cooperative radiation, resulting in an N-fold increase in the emission rate. In contrast to incoherent radiation, a superradiant system will produce a pulse of light with a shorter half-wave width, whose peak intensity is proportional to the square of the number of emitters N, but the overall energy remains unchanged. Existing studies have explored the theory behind the dipole-dipole interaction between superradiant atoms and observed superradiance in various artificial particle systems (such as ultracold nitrogen and quantum bits). However, these studies have placed strict requirements on the superradiance conditions, namely that all atoms should be within one wavelength, which greatly limits the scale of the superradiant system.

[0003] The spatial confinement of superradiance can be overcome by extending superradiance in a medium with a dielectric constant near-zero (ε) (ENZ). By embedding multiple quantum emitters within an ENZ medium, which describes a uniform spatial phase distribution, the emitted photons can interact with each quantum emitter, thereby extending the spatial region of superradiance from a single wavelength to a region far larger than a wavelength. Based on this principle, previous studies have proposed structures for achieving extended superradiance based on ENZ plasma channels, indium tin oxide thin films near the plasma frequency, and waveguides with cutoff wavelengths. However, the inherent ohmic losses of these metallic ENZ systems limit the superradiance power. To mitigate ohmic losses, existing research has proposed extending superradiance based on diamond ENZ metamaterials containing vacancy centers. However, these diamond ENZ metamaterials at visible wavelengths still face challenges in material purity and defect control, stress and strain management, and size and uniformity control. Furthermore, the emission wavelength of all these quantum optical superradiance systems is limited by the energy levels of the quantum emitters, such as atoms, ions, and artificial atoms. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the purpose of the present invention is to provide a superradiant pulse system based on zero-refractive-index metamaterials, which can realize superradiance in quantum theory with an emissivity multiplied by the number of sources in the microwave to terahertz frequency range. The zero-refractive-index environment frees traditional superradiance from the limitation of device size less than one wavelength, thus making it possible to extend superradiance without linear limitation.

[0006] In order to achieve the above objectives, the present invention adopts the following technical solutions.

[0007] The present invention provides a superradiant pulse system, comprising:

[0008] Support layer;

[0009] A zero-refractive-index metamaterial, comprising a plurality of metal pillars fixed to the support layer and arranged at periodic intervals, for achieving a zero-refractive-index environment for the radiation frequency of the superradiant pulse system;

[0010] A plurality of dipole transmitting antennas are distributed in corresponding gaps in the zero-refractive-index metamaterial, serving as superradiance emission sources to excite the superradiance radiation field of the superradiance pulse system to generate superradiance pulse signals;

[0011] The output end is used to output the super-radiant pulse signal with the lowest possible loss.

[0012] In some embodiments, the metal pillars in the zero-refractive-index metamaterial are made of the same material, and the electrical conductivity of the selected metal material should satisfy the requirement that the zero-refractive-index metamaterial achieves zero refractive index within a set frequency band.

[0013] In some embodiments, the metal pillars in the zero-refractive-index metamaterial are made of aluminum, gold, or copper to achieve a zero-refractive-index environment in the microwave frequency band.

[0014] In some embodiments, the cross-sectional shape of each metal pillar in the zero-refractive-index metamaterial has C4 symmetry.

[0015] In some embodiments, the refractive index of the interstitial medium between two adjacent metals in the zero-refractive-index metamaterial should satisfy the requirement that the zero-refractive-index metamaterial can achieve zero refractive index within a set frequency band.

[0016] In some embodiments, the interstitial medium between two adjacent metals in the zero-refractive-index metamaterial is selected from air, foam, or Teflon to achieve a zero-refractive-index environment in the microwave frequency band.

[0017] In some embodiments, the material of the support layer should have a refractive index equal to or close to that of the void medium in the zero-refractive-index metamaterial, and the support layer is provided with a plurality of holes for fixing the ends of the metal pillars in the zero-refractive-index metamaterial and embedding the dipole transmitting antenna.

[0018] In some embodiments, the center frequency of the dipole transmitting antenna is close to or equal to the characteristic frequency of the zero-refractive index metamaterial, so as to generate a superradiant pulse signal having a radiation frequency equal to the characteristic frequency of the zero-refractive index metamaterial.

[0019] In some embodiments, the output end uses an output antenna or an output waveguide;

[0020] The output antenna is a single dipole receiving antenna, and its end is embedded in the support layer;

[0021] The output waveguide is a single output waveguide. The support layer, the zero-refractive-index metamaterial, and the dipole transmitting antenna are packaged using a packaging structure, and a hole connected to the output waveguide is opened on the packaging structure.

[0022] In some embodiments, by adjusting the conductivity and structural characteristics of the metal pillars in the zero-refractive-index-exceeding material and the refractive index of the void medium, and selecting the dipole transmitting antenna with a center frequency equal to or close to the characteristic frequency of the zero-refractive-index-exceeding material, a super-radiant pulse system with a radiation frequency range from microwaves to terahertz is realized.

[0023] Compared with the prior art, the characteristics and beneficial effects of the present invention are:

[0024] This invention discloses a superradiant pulse system based on a zero-refractive-index metamaterial, a high-peak-power superradiant pulse source based on a low-loss zero-refractive-index medium composed of periodic aluminum pillars. By adjusting the radius and periodicity of the metal pillars within the metamaterial to achieve a zero-refractive-index environment at a specific microwave frequency, the invention achieves a special environment within the material where the equivalent radiation wavelength is infinite. In this environment, using multiple dipole transmitting antennas as radiation sources, extended superradiance can be achieved, unconstrained by device size or the energy level of the quantum emitter. Encapsulating this structure creates a high-power microwave superradiant pulse system whose input is multiple incoherent antenna transmission sources, and whose output peak power increases as the square of the number of radiation sources.

[0025] The advantages of the present application will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a three-dimensional diagram of a superradiant pulse system provided by an embodiment of the present invention. The figure does not illustrate the supporting layer in the system.

[0027] Figure 2 This is a top view of a superradiant pulse system provided by an embodiment of the present invention.

[0028] Figure 3 This is a comparison chart of the changes in superradiance and general radiation intensity over time generated by a superradiance pulse system provided by an embodiment of the present invention.

[0029] Figure 4 These are the quantitative results of simulation and experiment on the effectiveness test of a superradiant pulse system according to an embodiment of the present invention.

[0030] In the picture:

[0031] 1. Zero-refractive-index metamaterial, 2. Dipole transmitting antenna, 3. Output end, 4. Support layer.

[0032] Specific implementation method

[0033] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other in any manner.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from the description. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0035] The following further describes specific examples of the present invention with reference to the accompanying drawings: Example

[0036] See also Figure 1 、 Figure 2 An embodiment of the present invention provides a superradiant pulse system for generating a superradiant pulse signal in a microwave frequency band, the system comprising:

[0037] Support layer 4;

[0038] The zero-refractive-index metamaterial 1 comprises a plurality of periodically spaced metal pillars fixed to a support layer 4, and is used to achieve a zero-refractive-index environment for the radiation frequency of the superradiant pulse system;

[0039] Multiple dipole transmitting antennas 2 are distributed in corresponding gaps in the zero-refractive-index metamaterial 1 and serve as superradiance emission sources to stimulate the superradiance radiation field of the superradiance pulse system and generate superradiance pulse signals in the microwave frequency band;

[0040] The output terminal 3 is used to output a superradiant pulse signal with the lowest possible loss.

[0041] In some embodiments, the material of support layer 4 should have a refractive index equal to or close to that of the interstitial medium within zero-refractive-index metamaterial 1. In one specific embodiment of the present invention, an acrylic sheet is used as support layer 4. Support layer 4 is provided with a plurality of holes for securing the ends of the metal pillars within zero-refractive-index metamaterial 1 and for embedding the dipole transmitting antenna 2.

[0042] In some embodiments, the metal pillars in the zero-refractive-index metamaterial 1 are made of the same material, and the electrical conductivity of the selected metal material should satisfy the requirement that the zero-refractive-index metamaterial 1 can achieve zero refractive index within a set frequency band. For example, in order to achieve a zero-refractive-index environment in the microwave frequency band of the embodiment of the present invention, aluminum, gold, copper, etc. can be selected as the material of the metal pillars. The cross-section of each metal pillar adopts a circular cross-section or other cross-sectional shape with C4 symmetry. The gap medium between two adjacent metal pillars should be selected with a medium having a refractive index within a suitable range, so that the zero-refractive-index metamaterial 1 can achieve zero refractive index within a set frequency band. For example, in order to achieve a zero-refractive-index environment in the microwave frequency band of the embodiment of the present invention, the gap medium between two adjacent metal pillars can be air, foam, Teflon, etc.

[0043] Furthermore, by controlling the radius and spatial period of the metal pillars in the zero-refractive-index metamaterial 1, the metamaterial's equivalent refractive index is equal to or close to zero within a certain microwave bandwidth. The characteristic frequency of the zero-refractive-index metamaterial 1 (i.e., the frequency at which the equivalent refractive index is zero) corresponds to the center frequency of the dipole transmitting antenna 2. By adjusting the radius and spatial period of the metal pillars in the metamaterial, the characteristic frequency of the metamaterial can be tuned, thereby changing the frequency of the dipole transmitting antenna 2 and achieving microwave superradiation over a wide range. It should be noted that when regulating the zero-refractive-index metamaterial 1, the height of the metal pillars is not taken into account. Because the height has a negligible effect on the characteristic frequency of the metamaterial, the height of the metal pillars is generally set to a fixed value that is much larger than the radius and spatial period of the metal pillars.

[0044] In some embodiments, the number of dipole transmitting antennas 2 included in the present superradiant pulse system is N. All N dipole transmitting antennas 2 are commercially available, and the center frequency of each dipole transmitting antenna 2 should be close to or equal to the characteristic frequency of the zero-refractive-index metamaterial 1, so as to generate a superradiant pulse signal having a radiation frequency equal to the characteristic frequency of the zero-refractive-index metamaterial 1. The value of N can be selected based on the size of the zero-refractive-index metamaterial 1. To achieve the highest possible peak power superradiant pulse, the value of N should be based on the number of dielectric gaps filled with the zero-refractive-index metamaterial 1. It should be noted that when placing the dipole transmitting antennas 2 in the gaps of the zero-refractive-index metamaterial 1, physical contact between the dipole transmitting antennas 2 and the metal pillars in the zero-refractive-index metamaterial 1, which could cause a short circuit, should be avoided.

[0045] In some embodiments, the output terminal 3 can be an output antenna or an output waveguide. Furthermore, in order to make the output energy more concentrated, a dipole receiving antenna or an output waveguide should be used as the output terminal 3. If a dipole receiving antenna is selected as the output terminal 3, it can be directly placed in the corresponding gap of the zero-refractive-index metamaterial 1, and a hole for embedding and fixing the dipole receiving antenna should be reserved in the support layer 4. If a waveguide is selected as the output terminal 3, it is necessary to first Figure 1 The structure shown is encapsulated with metal on all sides, and then a hole is opened on one side of the metal encapsulation (the shape of the hole matches the cross-sectional shape of the waveguide used, such as a rectangular hole) and then connected to a standardized waveguide (such as a rectangular waveguide) corresponding to the pulse frequency of this superradiant pulse system.

[0046] The effectiveness of the embodiment of the present invention is verified below. First, a simulation analysis of the super-radiant pulse system of this embodiment is performed, followed by actual experimental tests, which are described as follows:

[0047] 1. Simulation analysis

[0048] The embodiment of the present invention uses the electromagnetic simulation software FDTD to complete the simulation analysis before the experiment. First, a zero-refractive index metamaterial 1 is constructed in FDTD, which consists of a periodic metal column array structure, and air is used as the gap material. Then a dipole transmitting antenna 2 is embedded in the gap of the zero-refractive index metamaterial 1. With the help of FDTD software, the phase characteristics of the field along the height direction of the metal column of the entire structure under different dipole antenna emission wavelengths can be analyzed. If it can be observed that the phase characteristics do not change with the spatial position near a certain emission wavelength, it proves that a zero-refractive index environment has been achieved. This is because in a zero-refractive index environment, the equivalent radiation wavelength of the electromagnetic wave is infinite, so the phase exhibits the same positive and negative characteristics. The emission wavelength at this time is the characteristic wavelength, and the corresponding frequency is the characteristic frequency of the zero-refractive index metamaterial 1. After determining the characteristic frequency, the time curve of the structural radiation field intensity after embedding N (N>1) dipole transmitting antennas 2 in the structure can be compared. See Figure 3Theoretically, the radiation intensity time curve b of a single dipole antenna is an exponentially decaying field with a pulse width of τ. Superradiance is achieved by stimulating dipole-dipole interactions between multiple dipole transmitting antennas 2. Compared to the radiation intensity time curve b of a single dipole antenna, the radiation intensity time curve a of the superradiance pulse system according to the present invention has a peak field intensity increased by N times, while the pulse width is reduced to τ / N. Therefore, in simulation software, if the peak value of the radiation intensity time curve at a characteristic frequency is higher than that at non-characteristic frequencies and decays faster, this qualitatively confirms the occurrence of superradiance. Further quantitative analysis is then performed to explore the quantitative relationship between the peak power of the superradiance pulse system and the number of transmitting sources N. In the simulation experiment, a dipole receiving antenna is used as the output terminal 3. The position of the dipole receiving antenna can be fixed, and then a gradually increasing number of dipole transmitting antennas 2 are placed around it in a circle with a fixed radius. By comparing the power variation of the dipole receiving antenna with different numbers of dipole transmitting antennas 2, quantitative measurement can be achieved.

[0049] After numerical simulation, the embodiment of the present invention finally adopts the following dimensional information of the zero-refractive index metamaterial 1: the radius of the metal column r = 2 mm, the periodicity a = 20 mm, the column height l = 200 mm, and the number of metal columns is 11×11=121. This can achieve a zero-refractive index environment with a characteristic frequency of 5.3GHz-5.4GHz within a space of 0.25×0.25×0.2 cubic meters. The dipole transmitting antenna 2 used in the embodiment of the present invention is a commercially purchased 1 / 4 wavelength dipole antenna with a center frequency of 5GHz and a bandwidth range of about 1GHz, which basically meets the requirements of the present invention. The embodiment of the present invention selects a dipole receiving antenna as the output end 3. Compared with the output waveguide, the dipole receiving antenna is light and easy to move, and is more suitable for the needs of the effectiveness verification experiment.

[0050] 2. Actual experimental test

[0051] Using the superradiant pulse system determined by the above-mentioned simulation molecules, the validity of the superradiant quantitative results can be explored in actual experiments using a vector network analyzer. Specifically, the output of port 1 of the vector network analyzer is connected to a power divider and then to 8 identical dipole transmitting antennas 2, thereby maintaining the same radiation characteristics of the 8 dipole transmitting antennas 2. The dipole transmitting antennas 2 are then placed one by one into the gaps of the zero-refractive index metamaterial 1, increasing the number of dipole transmitting antennas 2 in the zero-refractive index structure 1 from 1 to 8. During this process, it is necessary to maintain the same distance from the 8 dipole transmitting antennas 2 to the output terminal 3 to ensure that the field strength of each dipole transmitting antenna 2 after attenuation is the same when it reaches the output terminal 3, thereby avoiding the interference caused by the attenuation characteristics of the radiation field strength with distance on the quantitative measurement. Port 2 of the vector network analyzer is connected to the dipole receiving antenna located at the center of this superradiant pulse system. This dipole receiving antenna serves as the output terminal 3 to complete the measurement of the superradiant pulse signal. By recording the S21 parameter (the ratio of the 2-port input power to the 1-port output power) of the vector network analyzer and performing certain data processing, the quantitative results of the peak power of the radiation field of the superradiant pulse system can be obtained. Figure 4 This is a set of quantitative results obtained from testing the effectiveness of the microwave superradiant pulse system according to an embodiment of the present invention. The horizontal axis represents the number of dipole transmitting antennas 2, and the vertical axis represents the normalized peak power. Ideally, the normalized peak power of a superradiant pulse system should be proportional to the square of the number of dipole transmitting antennas 2. The dotted line in the figure represents the theoretical square relationship curve. The figure shows that both the simulation results (triangles) and the experimental results (squares) are distributed near the theoretical square relationship curve, thus verifying the effectiveness of the embodiment of the present invention.

[0052] It should be noted that the frequency band of the superradiant pulses generated by the superradiant pulse system of the present invention can be adjusted by varying the conductivity, radius, length, and periodicity of the metal pillar array, as well as the refractive index of the interstitial medium, thereby constructing a zero-refractive-index environment with characteristic frequencies ranging from microwaves to terahertz. Furthermore, by selecting a dipole transmitting antenna 2 with a center frequency equal to or close to the characteristic frequency, the present invention can be extended from a microwave frequency embodiment to a terahertz superradiant pulse system.

[0053] It can be understood that the superradiant pulse system provided by the present invention controls the radius and spatial period of the zero-refractive-index metamaterial so that its equivalent refractive index is equal to or close to zero within a certain microwave bandwidth. The characteristic frequency of the system (i.e., the frequency at which the equivalent refractive index is zero) corresponds to the center frequency of the dipole transmitting antenna. By adjusting the radius and spatial period of the metamaterial, its characteristic frequency can be tuned, thereby changing the frequency of the pulse emission source and achieving superradiance over a larger range. In view of the size restriction that all superradiant atoms should be within one wavelength, the present invention introduces a zero-refractive-index environment to achieve an equivalent refractive index of zero, that is, the equivalent radiation wavelength is infinite, thereby expanding the linearity of the superradiant system; in view of the fact that the emission wavelength of superradiance is limited by the energy levels of quantum emitters such as atoms, ions, and artificial atoms, a dipole antenna is innovatively used instead of a quantum emitter as a radiation source, thereby expanding the emission wavelength range of the superradiant system. The superradiant pulse system of the present invention has the characteristics of scalable peak power, scalable radiation wavelength, stability, and easy packaging.

[0054] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A superradiant pulse system, characterized in that: include: Support layer; A zero-refractive-index metamaterial, comprising a plurality of metal pillars fixed to the support layer and arranged at periodic intervals, for achieving a zero-refractive-index environment for the radiation frequency of the superradiant pulse system; A plurality of dipole transmitting antennas are distributed in corresponding gaps in the zero-refractive-index metamaterial, serving as superradiance emission sources to excite the superradiance radiation field of the superradiance pulse system to generate superradiance pulse signals; The output end is used to output the super-radiant pulse signal with the lowest possible loss.

2. The superradiant pulse system according to claim 1, characterized in that: The metal pillars in the zero-refractive-index metamaterial are made of the same material, and the electrical conductivity of the selected metal material should satisfy the requirement that the zero-refractive-index metamaterial can achieve zero refractive index within a set frequency band.

3. The superradiant pulse system according to claim 1, characterized in that: The metal pillars in the zero-refractive-index metamaterial are made of aluminum, gold, or copper to achieve a zero-refractive-index environment in the microwave frequency band.

4. The superradiant pulse system according to claim 1, characterized in that: The cross-sectional shape of each metal pillar in the zero-refractive-index metamaterial has C4 symmetry.

5. The superradiant pulse system according to claim 1, characterized in that: The refractive index of the interstitial medium between two adjacent metals in the zero-refractive-index metamaterial should satisfy the requirement that the zero-refractive-index metamaterial can achieve zero refractive index within a set frequency band.

6. The superradiant pulse system according to claim 1, characterized in that: The gap medium between two adjacent metals in the zero-refractive-index metamaterial is selected from air, foam or Teflon to achieve a zero-refractive-index environment in the microwave frequency band.

7. The superradiant pulse system according to claim 1, characterized in that: The material of the support layer should have a refractive index equal to or close to that of the void medium in the zero-refractive-index metamaterial. The support layer is provided with a plurality of holes for fixing the ends of the metal pillars in the zero-refractive-index metamaterial and embedding the dipole transmitting antenna.

8. The superradiant pulse system according to claim 1, characterized in that: The center frequency of the dipole transmitting antenna is close to or equal to the characteristic frequency of the zero-refractive-index metamaterial, so as to generate a superradiant pulse signal having a radiation frequency equal to the characteristic frequency of the zero-refractive-index metamaterial.

9. The superradiant pulse system according to claim 1, characterized in that: The output end adopts an output antenna or an output waveguide; The output antenna is a single dipole receiving antenna, and its end is embedded in the support layer; The output waveguide is a single output waveguide. The support layer, the zero-refractive-index metamaterial, and the dipole transmitting antenna are packaged using a packaging structure, and a hole connected to the output waveguide is opened on the packaging structure.

10. The super radiant pulse system according to any one of claims 1 to 9, characterized in that: By adjusting the conductivity and structural characteristics of the metal columns in the zero-refractive-index-exceeding material and the refractive index of the void medium, and selecting the dipole transmitting antenna whose center frequency is equal to or close to the characteristic frequency of the zero-refractive-index-exceeding material, a super-radiant pulse system with a radiation frequency range from microwaves to terahertz is realized.

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