Electromagnetic wave unidirectional cloaking apparatus and preparation method

Abstract

Provided in the present invention are an electromagnetic wave unidirectional cloaking apparatus and a preparation method, relating to the technical field of electromagnetic wave cloaking. The apparatus comprises a type I photonic crystal doped with loss impurities, a type II photonic crystal containing a cloaking substance, and a type I photonic crystal doped with gain impurities; the type I photonic crystal doped with loss impurities, the type II photonic crystal containing a cloaking susbtance, and the type I photonic crystal doped with gain impurities are arranged in sequence; the type I photonic crystals have Dirac-like dispersion and the type II photonic crystal has a photonic band gap, and the Dirac-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic band gap of the type II photonic crystal; the loss impurities doped into the type I photonic crystal and the gain impurities doped into the type I photonic crystal satisfy the following conditions: the relative dielectric constants thereof satisfy complex conjugation, and the relative magnetic permeability thereof is 1. The cloaking effect of the apparatus of the present invention is unidirectional, and the cloaking electromagnetic wave frequency is tunable.

Description

An electromagnetic wave one-way stealth device and its preparation method Technical Field

[0001] This invention relates to the field of electromagnetic wave stealth technology, and in particular to a one-way electromagnetic wave stealth device and its preparation method. Background Technology

[0002] Electromagnetic stealth technology has always been a hot research topic in both military and civilian fields. Its core objective is to reduce the detectability of the stealthed object, thereby evading enemy detection equipment or improving the security of civilian equipment. With the continuous development of technology, electromagnetic stealth technology has also undergone several stages of evolution, but many challenges and limitations still exist.

[0003] Traditional electromagnetic stealth methods mainly include absorption or directional scattering stealth, making the object appear transparent to the observer, and mimicry stealth. While these methods can achieve stealth effects to some extent, each has significant shortcomings. Absorption or directional scattering stealth technology reduces the scattered energy received by the detector by absorbing electromagnetic waves or adjusting the radar cross-section of the object. This method is effective when there is no background field in space, or when the background field is ignored as the measurement object. However, in complex backgrounds, the stealth effect may be greatly reduced, and it may even accelerate exposure due to interference from background information.

[0004] The method of making an object appear transparent to the observer involves suppressing the object's scattering, ensuring that the probe wave is neither scattered nor absorbed in any direction. While this physically perfect invisibility is extremely attractive, it places extremely stringent requirements on the electromagnetic parameters of the materials, making it very difficult to achieve in practice and thus hindering its widespread application.

[0005] Mimicry cloaking works by adjusting the scattered light of an object to resemble its background environment, thus blending into the background and achieving invisibility. However, the effectiveness of this method is heavily dependent on the specific background environment; once the background environment changes, the invisibility effect is greatly reduced, thus limiting its application scenarios.

[0006] In summary, while electromagnetic stealth technology has achieved some success, it still faces numerous challenges, particularly in achieving unidirectional electromagnetic stealth and tunability. Therefore, it is necessary to propose a new electromagnetic stealth device.

[0007] Summary of the Invention

[0008] To address this issue, this invention provides a unidirectional electromagnetic wave stealth device and its fabrication method, which solves the problem that existing technologies cannot achieve unidirectional electromagnetic wave stealth, i.e., stealth for electromagnetic waves incident from a specific direction, and generally lack tunability.

[0009] To address the aforementioned problems, this invention provides an electromagnetic wave one-way stealth device. The device includes a type I photonic crystal doped with loss impurities, a type II photonic crystal containing the object to be stolen, and a type I photonic crystal doped with gain impurities. The type I photonic crystal doped with loss impurities, the type II photonic crystal containing the object to be stolen, and the type I photonic crystal doped with gain impurities are arranged sequentially.

[0010] The type I photonic crystal has a Dirac cone-like dispersion, the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal.

[0011] The loss impurities and gain impurities doped in the type I photonic crystal satisfy the following conditions: their relative permittivity satisfies complex conjugation, and their relative permeability is 1.

[0012] In one embodiment of the present invention, the two-dimensional planar structure of the device specifically includes:

[0013] Both the type I photonic crystal doped with loss impurities and the type I photonic crystal doped with gain impurities are composed of dielectric cylinders arranged in a square lattice, with square loss impurities and gain impurities respectively doped in the middle.

[0014] The type II photonic crystal containing the cloaked object is composed of dielectric cylinders arranged in a square lattice, with a square cloaked object placed in the center.

[0015] In one embodiment of the present invention, the relative permittivity ε1 of the dielectric cylinder in the type I photonic crystal ranges from 3 to 50, the relative permeability is 1, the lattice constant a1 ranges from 0.01 mm to 1 m, and the radius r1 ranges from 0.05a1 to 0.5a1.

[0016] In one embodiment of the present invention, the side lengths of both the loss impurity and the gain impurity in the type I photonic crystal are 2a1, the relative permeability is 1, and the relative permittivity is ε. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... a1 represents the lattice constant, which ranges from 0.01 mm to 1 m.

[0017] In one embodiment of the present invention, the relative permittivity ε2 of the dielectric cylinder in the type II photonic crystal ranges from 3 to 50, the relative permeability is 1, the lattice constant a2 ranges from 0.01 mm to 1 m, and the radius r1 ranges from 0.05a2 to 0.5a2.

[0018] In one embodiment of the present invention, the three-dimensional structure of the device specifically includes:

[0019] Both the type I photonic crystal doped with loss impurities and the type I photonic crystal doped with gain impurities are composed of dielectric-metal composite spheres arranged in a cubic lattice, with square-section loss impurity dielectric pillars and gain impurity dielectric pillars respectively incorporated in the middle.

[0020] The type II photonic crystal containing the cloaked object is composed of dielectric-metal composite spheres arranged in a cubic lattice, with the cloaked object placed in the center.

[0021] In one embodiment of the present invention, the dielectric-metal composite sphere in the type I photonic crystal has a center with a radius of r. 1m A non-magnetic metal with an outer layer having a relative permittivity of ε. 1d Relative permeability is 1, radius is r 1d The dielectric shell, in which radius r 1m The value range is 0.01a1–0.4a1, and the relative permittivity ε 1d The value range is 3–50, and the radius r 1d The range of values ​​for r is 1m –0.5a1, where a1 represents the lattice constant, with a value ranging from 0.01 mm to 1 m.

[0022] In one embodiment of the present invention, the side length of the square-section loss impurity dielectric pillar and gain impurity dielectric pillar in the type I photonic crystal is a1, the relative permeability is 1, and the relative permittivity is ε. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... a1 represents the lattice constant, which ranges from 0.01 mm to 1 m.

[0023] In one embodiment of the present invention, the dielectric-metal composite sphere in the type II photonic crystal has a center with a radius of r. 2m A non-magnetic metal with an outer layer having a relative permittivity of ε. 2d Relative permeability is 1, radius is r 2dThe dielectric shell, in which radius r 2m The value range is 0.01a²–0.4a², and the relative permittivity ε 2d The value range is 3–50, and the radius r 2d The range of values ​​for r is 2m –0.5a2, where a2 represents the lattice constant, with a value ranging from 0.01 mm to 1 m.

[0024] This invention also provides a method for fabricating an electromagnetic wave one-way stealth device. This method, used to fabricate the aforementioned electromagnetic wave one-way stealth device, specifically includes:

[0025] Construct a type I photonic crystal and a type II photonic crystal such that the type I photonic crystal has a Dirac cone-like dispersion and the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal.

[0026] Construct loss impurities and gain impurities such that their relative permittivity satisfies complex conjugation and their relative permeability is 1;

[0027] The loss impurity and the gain impurity are respectively incorporated into the type I photonic crystal to obtain a type I photonic crystal doped with loss impurities and a type I photonic crystal doped with gain impurities. The cloaked object is placed in a type II photonic crystal to obtain a type II photonic crystal containing the cloaked object.

[0028] The electromagnetic wave unidirectional stealth device is fabricated by sequentially arranging the type I photonic crystal doped with loss impurities, the type II photonic crystal containing the object to be hidden, and the type I photonic crystal doped with gain impurities.

[0029] As can be seen from the above technical solutions, this invention application has the following beneficial effects:

[0030] This invention provides a unidirectional electromagnetic wave stealth device and its fabrication method. The device can achieve electromagnetic wave stealth for objects placed at the center of a type II photonic crystal, and this stealth effect is independent of the material of the object being stealthed. The stealth effect of this device is unidirectional, meaning it only has stealth characteristics for electromagnetic waves incident on one side of a type I photonic crystal doped with lossy impurities. In this case, the electromagnetic wave reflection is approximately 0, the transmittance is close to 1, and the outgoing wave maintains a flat wavefront. The stealth electromagnetic wave frequency of this device is tunable; the frequency can be changed by altering the structural dimensions of the photonic crystal. The stealth electromagnetic wave frequency can, in principle, be located in the microwave, terahertz, infrared, or visible light bands. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below. Referring to the accompanying drawings will provide a clearer understanding of the features and advantages of the present invention. The drawings are illustrative and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort. Wherein:

[0032] Figure 1 is a schematic diagram of the structure of an electromagnetic wave one-way stealth device provided in the embodiment;

[0033] Figure 2 is a schematic diagram of the two-dimensional stealth device in the embodiment;

[0034] Figure 3 shows the energy band diagrams of the Type I and Type II photonic crystals in the two-dimensional stealth device in the embodiment;

[0035] Figure 4 shows the numerical simulation results of the two-dimensional stealth device in the embodiment;

[0036] Figure 5 is a schematic diagram of the three-dimensional stealth device in the embodiment;

[0037] Figure 6 shows the energy band diagrams of the Type I and Type II photonic crystals in the three-dimensional stealth device in the embodiment;

[0038] Figure 7 shows the numerical simulation results of the three-dimensional stealth device in the embodiment;

[0039] Figure 8 is a flowchart of a method for preparing an electromagnetic wave unidirectional stealth device provided in the embodiment.

[0040] The following symbols are used in the instruction manual: 1. Type I photonic crystal; 2. Type II photonic crystal; 3. Loss impurity; 4. Gain impurity; 5. The object being hidden. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0042] Example 1

[0043] To address the problem that existing technologies cannot achieve unidirectional electromagnetic wave stealth, i.e., stealth for electromagnetic waves incident from a specific direction, and generally lack tunability, this invention proposes a unidirectional electromagnetic wave stealth device, as shown in Figure 1. This device includes a type I photonic crystal 1 doped with loss impurities 3, a type II photonic crystal 2 containing the object to be stolen 5, and a type I photonic crystal 1 doped with gain impurities 4. The type I photonic crystal 1 doped with loss impurities 3, the type II photonic crystal 2 containing the object to be stolen 5, and the type I photonic crystal 1 doped with gain impurities 4 are arranged sequentially.

[0044] The type I photonic crystal 1 has a Dirac cone-like dispersion, the type II photonic crystal 2 has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal 1 is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal 2.

[0045] The loss impurity 3 and the gain impurity 4 doped in the type I photonic crystal 1 satisfy the following conditions: their relative permittivity satisfies complex conjugation and their relative permeability is 1.

[0046] As can be seen from the above technical solution, this invention proposes a unidirectional electromagnetic wave stealth device, comprising a type I photonic crystal doped with loss impurities, a type II photonic crystal containing the object to be stolen, and a type I photonic crystal doped with gain impurities. The type I photonic crystal exhibits a Dirac cone-like dispersion, the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal. The loss impurities doped in the type I photonic crystal and the gain impurities doped in the type I photonic crystal satisfy the following conditions: their relative permittivity satisfies complex conjugation, and their relative permeability is 1. This invention's device can achieve electromagnetic wave stealth for an object placed at the center of the type II photonic crystal, and this stealth effect is independent of the material of the object being stolen. The stealth effect of this invention's device is unidirectional, meaning it only has stealth characteristics for electromagnetic waves incident on the side of the type I photonic crystal doped with loss impurities. At this time, the electromagnetic wave reflection is approximately 0, the transmittance is close to 1, and the outgoing wave maintains a flat wavefront. The stealth electromagnetic wave frequency of the device of this invention is tunable; by changing the structural dimensions of the photonic crystal, the frequency of the stealth electromagnetic wave can be altered. In principle, the stealth electromagnetic wave frequency can be located in the microwave, terahertz, infrared, or visible light bands.

[0047] In this embodiment, the present invention designs an electromagnetic wave unidirectional cloaking device consisting of a type I photonic crystal 1 doped with loss impurities 3 on the left, a type II photonic crystal 2 containing the cloaked object 5 in the middle, and a type I photonic crystal 2 doped with gain impurities 4 on the right, as shown in Figure 1. Specifically, the type I photonic crystal 1 has a Dirac cone-like dispersion, and the type II photonic crystal 2 has a photonic bandgap, and must satisfy the following: the Dirac cone-like point frequency of the type I photonic crystal 1 is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal 2. For the loss impurities 3 doped in the type I photonic crystal 1 on the left and the gain impurities 4 doped in the type I photonic crystal 1 on the right, the following conditions must be met: their relative permittivity satisfies complex conjugation, and their relative permeability is 1.

[0048] Furthermore, a hidden object 5 is placed at the center of the Type II photonic crystal 2. Without the hidden object, the central object would strongly scatter the incident electromagnetic waves, making it easily detectable. However, under appropriate parameters, the device can achieve unidirectional cloaking of electromagnetic waves, meaning that electromagnetic waves incident from the left can pass through the entire device without reflection, maintaining a completely flat wavefront, unaffected by the central object.

[0049] The mechanism of the stealth device of this invention is as follows: A type I photonic crystal 1 doped with loss impurities 3 can absorb most of the incident electromagnetic waves, and the remaining small portion of electromagnetic energy is transferred to the right-side type I photonic crystal 1 via a type II photonic crystal 2. The electromagnetic energy is amplified by gain impurities 4 doped into the right-side type I photonic crystal 1, allowing the incident electromagnetic waves to be recovered on the right side. During this process, because the electromagnetic energy in the type II photonic crystal 2 is very low, the object to be stolen 5 placed in the middle will not significantly affect the overall transmission of the electromagnetic waves. Furthermore, the electromagnetic waves exhibit diffraction characteristics in the type II photonic crystal 2, which is located at the band edge frequency, enabling them to bypass the stolen object and ultimately achieve the stealth effect of the electromagnetic waves.

[0050] It should be noted that the above mechanism only applies to electromagnetic waves incident from the side of the Type I photonic crystal 1 doped with loss impurities 3. If the electromagnetic waves are incident from the side of the Type I photonic crystal 1 doped with gain impurities 4, there will be no electromagnetic wave stealth effect. Therefore, this electromagnetic wave stealth device is only effective for unidirectional incident electromagnetic waves, i.e., it is a unidirectional electromagnetic wave stealth device.

[0051] The stealth device can be either a two-dimensional planar structure or a three-dimensional solid structure. Specific implementation examples are as follows.

[0052] Figure 2 shows a schematic diagram of the two-dimensional stealth device. Both the Type I photonic crystal 1 (left) doped with loss impurity 3 and the Type I photonic crystal 1 (right) doped with gain impurity 4 are constructed from dielectric cylinders arranged in a cubic lattice. The dielectric cylinders have a relative permittivity ε1 ranging from 3 to 50, a relative permeability of 1, a lattice constant a1 ranging from 0.01 mm to 1 m, and a radius r1 ranging from 0.05a1 to 0.5a1. In the Type I photonic crystal 1, both the loss impurity 3 and the gain impurity 4 have a side length of 2a1, a relative permeability of 1, and relative permittivity ε1 and ε2, respectively. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... (The real parts are the same, and the imaginary parts are opposites of each other).

[0053] The Type II photonic crystal 2 containing the cloaked object 5 is composed of dielectric cylinders arranged in a square lattice, with the square cloaked object 5 placed in the center. The relative permittivity ε2 of the dielectric cylinders ranges from 3 to 50, the relative permeability is 1, the lattice constant a2 ranges from 0.01 mm to 1 m, and the radius r1 ranges from 0.05a2 to 0.5a2.

[0054] To achieve electromagnetic stealth, Type I photonic crystal 1 must possess a Dirac cone-like dispersion, and Type II photonic crystal 2 must possess a photonic bandgap. Furthermore, the following conditions must be met: the Dirac cone-like point frequency of Type I photonic crystal 1 must be the same as the band edge frequency of the photonic bandgap of Type II photonic crystal 2. This condition can be satisfied by adjusting the geometric and electromagnetic parameters of the two types of photonic crystals. Here, we take a1 = a2 = 16.2 mm, r1 = 3.75 mm, r2 = 3.55 mm, and ε1 = ε2 = 7.5.

[0055] Figure 3 shows the band diagrams of type I photonic crystal 1 and type II photonic crystal 2. It can be seen that type I photonic crystal 1 has a Dirac cone-like dispersion, while type II photonic crystal 2 has a significant photonic band gap. Furthermore, the Dirac cone-like point frequency of type I photonic crystal 1 is the same as the band edge frequency of the lower band of type II photonic crystal 2, both at 11.17 GHz.

[0056] To achieve electromagnetic wave stealth, the relative permittivity ε of the impurities doped in the Type I photonic crystal 1 also needs to be satisfied. d,L and ε d,R They are complex conjugates. Through parameter optimization, ε is chosen. d,L =1.84+0.26i, ε d,R =1.84-0.26i.

[0057] Figure 4 shows the simulation results using numerical software. A plane electromagnetic wave with a frequency of 11.17 GHz is incident from the air end on the left, and the center of the stealth device is a square object 5 to be hidden. The simulation results show that the electromagnetic wave reflectivity is about 0, the transmittance is close to 1, and the emitted electromagnetic wave maintains a flat wavefront, which indicates that the device has good electromagnetic wave stealth characteristics.

[0058] This stealth principle can also be extended to three-dimensional models. Figure 5 shows a schematic diagram of the three-dimensional stealth device. Both the Type I photonic crystal 1 (left) doped with loss impurity 3 and the Type I photonic crystal 1 (right) doped with gain impurity 4 are composed of dielectric-metal composite spheres arranged in a cubic lattice. In the Type I photonic crystal 1, the center of the dielectric-metal composite sphere has a radius of r. 1m Non-magnetic metals (such as copper and aluminum) with an outer layer having a relative permittivity of ε 1d Relative permeability is 1, radius is r 1d The dielectric shell, in which radius r 1m The value range is 0.01a1–0.4a1, and the relative permittivity ε 1d The value range is 3–50, and the radius r 1d The range of values ​​for r is 1m –0.5a1, where a1 represents the lattice constant, ranging from 0.01 mm to 1 m. Between the layers are square-section loss impurity 3 dielectric pillars and gain impurity 5 dielectric pillars, each with a side length of a1, a relative permeability of 1, and relative permittivity ε. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... (The real parts are the same, and the imaginary parts are opposites of each other).

[0059] The Type II photonic crystal 2, containing the cloaked object 5, is composed of dielectric-metal composite spheres arranged in a cubic lattice, with the cloaked object 5 placed in the center. The dielectric-metal composite spheres in the Type II photonic crystal 2 have a center radius of r. 2m Non-magnetic metals (such as copper and aluminum) with an outer layer having a relative permittivity of ε 2d Relative permeability is 1, radius is r 2d The dielectric shell, in which radius r 2m The value range is 0.01a²–0.4a², and the relative permittivity ε 2d The value range is 3–50, and the radius r 2d The range of values ​​for r is 2m–0.5a2, where a2 represents the lattice constant, with a value ranging from 0.01 mm to 1 m.

[0060] Similar to the two-dimensional model, to achieve electromagnetic wave invisibility, Type I photonic crystal 1 must possess a Dirac cone-like dispersion, and Type II photonic crystal 2 must possess a band gap. Furthermore, the following conditions must be met: the Dirac cone-like point frequency of Type I photonic crystal 1 must be the same as the band edge frequency of the band gap of Type II photonic crystal 2. This condition can be satisfied by adjusting the geometric and electromagnetic parameters of the two types of photonic crystals. Here, we take a1 = a2 = 12.8 mm, r... 1m =1.61mm, r 1d =5.12mm, r 2m =1.92mm, r 2d =4.65mm, ε1=30, ε 2d =35.03.

[0061] Figure 6 shows the three-dimensional band diagrams of Type I photonic crystal 1 and Type II photonic crystal 2. It can be seen that Type I photonic crystal 1 has a significant photonic band gap, while Type II photonic crystal 2 has a Dirac cone-like dispersion. Furthermore, the band edge frequencies of the two lower bands of Type I photonic crystal 1 are the same as the Dirac cone-like point frequencies of Type II photonic crystal 2, both at 6.274 GHz.

[0062] To achieve electromagnetic wave stealth, the relative permittivity ε of the impurities doped in the Type I photonic crystal 1 also needs to be satisfied. d,L and ε d,R They are complex conjugates. Through parameter optimization, ε is chosen. d,L =0.5+2.1i,ε d,R =0.5-2.1i.

[0063] Figure 7 shows the simulation results using numerical software. A plane electromagnetic wave with a frequency of 6.274 GHz is incident from the air end on the left, and the center of the stealth device is a cubic object 5 being concealed. The simulation results show that the electromagnetic wave reflectivity is approximately 0, the transmittance is close to 1, and the emitted electromagnetic wave maintains a flat wavefront, indicating that the device has excellent electromagnetic wave stealth characteristics.

[0064] Example 2

[0065] As shown in Figure 8, the present invention provides a method for preparing an electromagnetic wave one-way stealth device. This method is used to prepare the electromagnetic wave one-way stealth device of Embodiment 1 above, and specifically includes:

[0066] Construct a type I photonic crystal and a type II photonic crystal such that the type I photonic crystal has a Dirac cone-like dispersion and the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal.

[0067] Construct loss impurities and gain impurities such that their relative permittivity satisfies complex conjugation and their relative permeability is 1;

[0068] The loss impurity and the gain impurity are respectively incorporated into the type I photonic crystal to obtain a type I photonic crystal doped with loss impurities and a type I photonic crystal doped with gain impurities. The cloaked object is placed in a type II photonic crystal to obtain a type II photonic crystal containing the cloaked object.

[0069] The electromagnetic wave unidirectional stealth device is fabricated by sequentially setting up the type I photonic crystal doped with loss impurities, the type II photonic crystal containing the object to be cloaked, and the type I photonic crystal doped with gain impurities.

[0070] This embodiment provides a method for preparing an electromagnetic wave one-way stealth device, which is used to prepare the aforementioned electromagnetic wave one-way stealth device. Therefore, the specific implementation method of the electromagnetic wave one-way stealth device preparation method can be found in the previous section on the embodiment of the electromagnetic wave one-way stealth device. To avoid redundancy, it will not be repeated here.

[0071] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A one-way electromagnetic wave stealth device, characterized in that, It includes a type I photonic crystal doped with loss impurities, a type II photonic crystal containing the object to be hidden, and a type I photonic crystal doped with gain impurities, wherein the type I photonic crystal doped with loss impurities, the type II photonic crystal containing the object to be hidden, and the type I photonic crystal doped with gain impurities are arranged sequentially. The type I photonic crystal has a Dirac cone-like dispersion, the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal. The loss impurities and gain impurities doped in the type I photonic crystal satisfy the following conditions: their relative permittivity satisfies complex conjugation, and their relative permeability is 1.

2. The electromagnetic wave unidirectional stealth device according to claim 1, characterized in that, The two-dimensional planar structure of the device specifically includes: Both the type I photonic crystal doped with loss impurities and the type I photonic crystal doped with gain impurities are composed of dielectric cylinders arranged in a square lattice, with square loss impurities and gain impurities respectively doped in the middle. The type II photonic crystal containing the cloaked object is composed of dielectric cylinders arranged in a square lattice, with a square cloaked object placed in the center.

3. The electromagnetic wave unidirectional stealth device according to claim 2, characterized in that, The relative permittivity ε1 of the dielectric cylinder in the type I photonic crystal ranges from 3 to 50, the relative permeability is 1, the lattice constant a1 ranges from 0.01 mm to 1 m, and the radius r1 ranges from 0.05a1 to 0.5a1.

4. The electromagnetic wave unidirectional stealth device according to claim 2, characterized in that, The type I photonic crystal has a side length of 2a1 for both the loss impurity and the gain impurity, a relative permeability of 1, and relative permittivity of ε. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... a1 represents the lattice constant, which ranges from 0.01 mm to 1 m.

5. The electromagnetic wave unidirectional stealth device according to claim 2, characterized in that, The relative permittivity ε2 of the dielectric cylinder in the type II photonic crystal ranges from 3 to 50, the relative permeability is 1, the lattice constant a2 ranges from 0.01 mm to 1 m, and the radius r1 ranges from 0.05a2 to 0.5a2.

6. The electromagnetic wave unidirectional stealth device according to claim 1, characterized in that, The three-dimensional structure of the device specifically includes: Both the type I photonic crystal doped with loss impurities and the type I photonic crystal doped with gain impurities are composed of dielectric-metal composite spheres arranged in a cubic lattice, with square-section loss impurity dielectric pillars and gain impurity dielectric pillars respectively incorporated in the middle. The type II photonic crystal containing the cloaked object is composed of dielectric-metal composite spheres arranged in a cubic lattice, with the cloaked object placed in the center.

7. The electromagnetic wave unidirectional stealth device according to claim 6, characterized in that, In the type I photonic crystal, the dielectric-metal composite sphere has a center with a radius of r. 1m A non-magnetic metal with an outer layer having a relative permittivity of ε. 1d Relative permeability is 1, radius is r 1d The dielectric shell, in which radius r 1m The value range is 0.01a1–0.4a1, and the relative permittivity ε 1d The value range is 3–50, and the radius r 1d The range of values ​​for r is 1m –0.5a1, where a1 represents the lattice constant, with a value ranging from 0.01 mm to 1 m.

8. The electromagnetic wave unidirectional stealth device according to claim 6, characterized in that, In the type I photonic crystal, the side length of the square-section loss impurity dielectric pillar and gain impurity dielectric pillar is a1, the relative permeability is 1, and the relative permittivity is ε. d,L and ε d,R , ε d,L and ε d,R The value range of ε is: both the real and imaginary parts are 3–50, where ε is... d,L and ε d,R They are mutually conjugate, that is... a1 represents the lattice constant, which ranges from 0.01 mm to 1 m.

9. The electromagnetic wave unidirectional stealth device according to claim 6, characterized in that, In the type II photonic crystal, the dielectric-metal composite sphere has a center with a radius of r. 2m A non-magnetic metal with an outer layer having a relative permittivity of ε. 2d Relative permeability is 1, radius is r 2d The dielectric shell, in which radius r 2m The value range is 0.01a²–0.4a², and the relative permittivity ε 2d The value range is 3–50, and the radius r 2d The range of values ​​for r is 2m –0.5a2, where a2 represents the lattice constant, with a value ranging from 0.01 mm to 1 m.

10. A method for fabricating a one-way electromagnetic wave stealth device, characterized in that, The method is used to prepare the electromagnetic wave unidirectional stealth device according to any one of claims 1 to 9, specifically comprising: Construct a type I photonic crystal and a type II photonic crystal such that the type I photonic crystal has a Dirac cone-like dispersion and the type II photonic crystal has a photonic bandgap, and the Dirac cone-like point frequency of the type I photonic crystal is the same as the band edge frequency of the photonic bandgap of the type II photonic crystal. Construct loss impurities and gain impurities such that their relative permittivity satisfies complex conjugation and their relative permeability is 1; The loss impurity and the gain impurity are respectively incorporated into the type I photonic crystal to obtain a type I photonic crystal doped with loss impurities and a type I photonic crystal doped with gain impurities. The cloaked object is placed in a type II photonic crystal to obtain a type II photonic crystal containing the cloaked object. The electromagnetic wave unidirectional stealth device is fabricated by sequentially arranging the type I photonic crystal doped with loss impurities, the type II photonic crystal containing the object to be hidden, and the type I photonic crystal doped with gain impurities.

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