CN114552332A - Cerenkov infrared radiation source and free electron light source based on natural hyperbolic material - Google Patents
Cerenkov infrared radiation source and free electron light source based on natural hyperbolic material Download PDFInfo
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Abstract
The invention provides a Cerenkov infrared radiation source and a free electron light source based on a natural hyperbolic material. Therefore, stable electron beams are generated through the on-chip free electron emission source, and infrared Cerenkov radiation in the natural hyperbolic material is excited. The natural hyperbolic metamaterial is low in cost, easy to obtain and simple in preparation process, and has remarkable advantages compared with an artificial hyperbolic metamaterial. Meanwhile, the natural hyperbolic material is easy to grow and has good stability and few defects, and the influence on the performance of the device caused by the processing precision of the material can be avoided. And based on natural medium materials, the intrinsic loss is lower, so that the corresponding device has higher radiation power, higher efficiency and less heat generation. In addition, based on natural crystal materials, territory and array are easy to realize, and a possible scheme is provided for the high-power array integrated free electron light source.
Description
Technical Field
The invention relates to the technical field of integrated light sources, in particular to a Cerenkov infrared radiation source and a free electronic light source based on a natural hyperbolic material.
Background
Mid-Far infrared (Mid-Far infrared) waves refer to electromagnetic waves with a wavelength of 2.5 μm to 25 μm. The medium and far infrared waves can generate resonance with most molecules, have stronger thermal effect and can be used for analyzing and identifying substances. In addition, the medium and far infrared waves have stronger diffraction resistance, have better penetrating power in the atmospheric environment and are more favorable for the remote transmission of information. Therefore, electromagnetic waves in the mid-far infrared to terahertz (THz) region are considered as one of the future important technologies.
Cerenkov Radiation (CR) refers to electromagnetic Radiation generated when the free electron velocity of uniform flight is greater than the phase velocity of light in the surrounding medium. When the free electron velocity is smaller than the speed of light in the surrounding medium, its surrounding electromagnetic field behaves as an evanescent field perpendicular to the flight direction, with no radiation generation. When the free electron velocity is greater than the light velocity in the surrounding medium, the vertical electromagnetic field appears as a propagation field, and the generated electromagnetic radiation is CR. CR has wide application, and can be applied to the fields of detection and analysis of high-energy cosmic rays and particles, electromagnetic imaging of biomedicine and the like.
At present, a common Cerenkov infrared radiation source based on a hyperbolic material is designed based on an artificial hyperbolic metamaterial. Hyperbolic Meta-Materials (HMMs) refer to multilayer film artificial metamaterials formed by stacking metal and medium layers, and the dielectric constant epsilon of metal is in a specific wavebandm<0, and the dielectric constant ε of the mediumd>0, the equivalent dielectric constant of the whole multilayer film material is positive and negative in the directions parallel to the film layers and perpendicular to the film layers, so that the hyperbolic property is formed.
However, the free electron radiation device prepared by using the artificially constructed hyperbolic metamaterial has the following problems:
(1) because the thickness of each layer is required to be small enough and the number of layers is generally more than 10, the preparation process of the hyperbolic metamaterial is complex, and the property of the material is directly influenced by the processing precision, so that the stability of the device is poor.
(2) Because the radiation in the artificial hyperbolic metamaterial is essentially interlayer coupling of metal layer plasma, the artificial hyperbolic metamaterial inevitably has large intrinsic loss, and therefore the radiation power density and the luminous intensity of the device are limited.
(3) Due to the influence of the process for manually preparing the hyperbolic metamaterial, the size of the hyperbolic metamaterial is difficult to be enlarged, so that the related light source devices are difficult to integrate and array, and the output power and the practicability of the devices are limited.
Disclosure of Invention
The invention aims to provide a Cerenkov infrared radiation source and a free electron light source based on a natural hyperbolic material, which are used for solving the problems of high cost, complex process, poor stability and the like of a free electron radiation source based on an artificial hyperbolic metamaterial in the prior art, greatly reducing the preparation cost and process complexity of a device and avoiding the influence on the performance of the device caused by a material processing process to the greatest extent.
The invention provides a Cerenkov infrared radiation source based on a natural hyperbolic material, which comprises:
a layer of natural hyperbolic material;
and the on-chip free electron emission source is arranged on one side of the natural hyperbolic material layer and comprises an on-chip electron source cathode and an on-chip electron source anode.
The Cerenkov infrared radiation source based on the natural hyperbolic material further comprises a nano-pillar array extraction structure, the nano-pillar array extraction structure is arranged on the other side of the natural hyperbolic material layer, and the nano-pillar array extraction structure is used for extracting Cerenkov radiation generated inside the natural hyperbolic material layer.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the natural hyperbolic material layer is made of calcite, hexagonal boron nitride, graphite, quartz and NaNO3Crystals or Al2O3And (4) crystals.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the thickness of the natural hyperbolic material layer is smaller than or equal to 1 mm.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the nano-column array extraction structure comprises a plurality of nano-columns arranged at intervals, and the nano-columns are made of gold.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the extraction structures of the nano-column arrays are arranged in a square, hexagonal or random manner.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the diameter of each nano column is 10nm to 5 mu m, and/or the distance between every two adjacent nano columns is 100nm to 20 mu m.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the free electron emission source on the chip is made of gold, molybdenum, platinum, graphene or a carbon nano tube.
According to the Cerenkov infrared radiation source based on the natural hyperbolic material, the cathode of the on-chip electron source is in a needle point shape, a sawtooth shape, a triangular shape or a conical shape.
The invention also provides a free electron light source which comprises the Cerenkov infrared radiation source based on the natural hyperbolic material.
The Cerenkov infrared radiation source based on the natural hyperbolic material comprises a natural hyperbolic material layer and an on-chip free electron emission source arranged on one side of the natural hyperbolic material layer, wherein the on-chip free electron emission source comprises an on-chip electron source cathode and an on-chip electron source anode. According to the arrangement, the stable free electron beam is generated through the on-chip free electron emission source, and the infrared Cerenkov radiation in the natural hyperbolic material layer is excited. The natural hyperbolic metamaterial is low in cost, easy to obtain and simple in preparation process, and has remarkable advantages compared with an artificial hyperbolic metamaterial. Meanwhile, as the natural hyperbolic material is easy to grow, good in stability and few in defects, the influence on the device performance caused by the material processing process precision can be avoided to the greatest extent. And based on natural medium materials, the intrinsic loss is lower, so that the corresponding device has higher radiation power, higher efficiency and less heat generation. In addition, based on natural crystal materials, territory and array are easy to realize, the integration level and the space efficiency of related devices are greatly improved, and a possible scheme is provided for a high-power array integrated free electron light source.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a perspective view of a Cerenkov infrared radiation source based on natural hyperbolic material provided by the invention;
FIG. 2 is a front view of a Cerenkov infrared radiation source based on natural hyperbolic material provided by the invention;
FIG. 3 is a bottom view of a Cerenkov infrared radiation source based on natural hyperbolic material provided by the invention;
figure 4 is a schematic structural diagram of calcite crystals provided by the present invention;
FIG. 5 shows the dielectric constant (. epsilon.) of calcite crystals provided by the present invention in the direction perpendicular to the optical axisx，εz) A distribution diagram;
FIG. 6 shows the dielectric constant (. epsilon.) of calcite crystals provided by the present invention in the direction parallel to the optical axisy) A distribution diagram;
FIG. 7 is an iso-frequency wavevector diagram of calcite crystals at the 44THz frequency point provided by the present invention;
fig. 8 is a schematic diagram of the CR mode of extraction of calcite crystals by a single nanocolumn provided by the present invention;
reference numerals:
1: a layer of natural hyperbolic material; 2: an on-chip electron source cathode; 3: an on-chip electron source anode; 4: a nanopillar array extraction structure; 41: and (4) nano columns.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The cerenkov infrared radiation source based on natural hyperbolic material of the present invention is described below with reference to fig. 1 to 8.
As shown in fig. 1, an embodiment of the present invention provides a cerenkov infrared radiation source based on a natural hyperbolic material, which includes a natural hyperbolic material layer 1 and an on-chip free electron emission source. Specifically, the natural hyperbolic material layer 1 is in a sheet shape or a strip shape, and of course, other figures are possible, and the specific shape thereof may be determined according to actual design requirements. Natural hyperboloid Materials (Natural hyperboloid Materials) refer to Natural dielectric Materials having anisotropic hyperboloid properties in a specific wavelength band, where the hyperboloid properties refer to that dielectric constant of the material in a specific direction (crystal direction) is negative in a specific Frequency range, dielectric constant of the material in other directions is positive, and an Iso-Frequency wave vector (IFC) of the material shows a hyperboloid shape. The natural hyperbolic material can support coupling transmission of a maximum wave vector electromagnetic mode, so that the natural hyperbolic material has a maximum optical local state density and can be used for preparing an integrated light source. Meanwhile, the free electrons can excite non-threshold Cerenkov radiation in the natural hyperbolic material, and a free electron light source based on the natural hyperbolic material is expected to be prepared.
As shown in fig. 2, the on-chip free electron emission source is disposed on one side of the natural hyperbolic material layer 1. Specifically, the on-chip free electron emission source comprises an on-chip electron source cathode 2 and an on-chip electron source anode 3 which are respectively arranged at the left end and the right end of the natural hyperbolic material layer 1. The structure of the cathode 2 of the on-chip electron source is different according to different experimental schemes, and mainly comprises a needle point electron source, an on-chip metal electrode and the like. When the on-chip electron source cathode 2 works, high negative bias voltage is applied to emit stable free electron beams to excite infrared Cherenkov radiation in the natural hyperbolic material layer 1. The electron energy of the direct current electron beam is 0.1keV to 5keV, the current is 10nA to 100 muA, the beam spot diameter of the electron beam is 100nm to 100μm, and the performance of different types of on-chip electron sources is different. The on-chip electron source anode 3 serves as an electron collector and is used for receiving electrons flying across the surface of the natural hyperbolic material layer 1. When the on-chip electron source anode 3 works, positive bias is applied, so that a gap between the cathode and the anode generates a large unidirectional electric field, which is beneficial to realizing the directional flight of the vacuum electron beam emitted by the cathode and the efficient interaction with natural crystals. The type of the on-chip free electron emission source is not limited, and the cathode-anode distance, namely the free electron action distance, can be flexibly adjusted according to the actual device requirements. In addition, the left-right direction in the drawing is the left-right direction in terms of the placement position of the cerenkov infrared radiation source based on the natural hyperbolic material as shown in fig. 2.
According to the arrangement, the stable free electron beam is generated through the on-chip free electron emission source, and infrared Cerenkov radiation in the natural hyperbolic material is excited. The natural hyperbolic metamaterial is low in cost, easy to obtain and simple in preparation process, and has remarkable advantages compared with an artificial hyperbolic metamaterial. Meanwhile, as the natural hyperbolic material is easy to grow, good in stability and few in defects, the influence on the device performance caused by the material processing process precision can be avoided to the greatest extent. And based on natural medium materials, the intrinsic loss is lower, so that the corresponding device has higher radiation power, higher efficiency and less heat generation. In addition, based on natural crystal materials, territory and array are easy to realize, the integration level and the space efficiency of related devices are greatly improved, and a possible scheme is provided for a high-power array integrated free electron light source.
Further, the Cerenkov infrared radiation source based on the natural hyperbolic material further comprises a nano-pillar array extraction structure 4 for extracting infrared Cerenkov radiation generated inside the natural hyperbolic material layer 1. As shown in fig. 2, the nanopillar array extraction structure 4 is disposed on the other side of the natural hyperbolic material layer 1. It should be noted that the CR mode excited by the free electrons inside the natural dielectric material is essentially phonon polariton of the natural dielectric material, for example, for calcite crystal, or surface plasmon of the natural dielectric material, and when the CR propagates to the surface of the natural dielectric material, it is bound inside the material due to the large refractive index difference between the material and the vacuum environment. Through the arrangement of the nano-column array, a phonon excimer mode or a surface plasmon propagated to the surface of the natural medium material can form a local resonance mode at the position of the nano-column, local enhancement of a radiation field is realized at the position of the nano-column, and large wave vector matching is realized, so that extraction from a crystal phonon polariton or a surface plasmon to a vacuum radiation mode is realized. By the design, the scattering extraction is realized by utilizing the wave vector compensation effect at the edge of the nano-column to the CR mode of the phonon excimer or the surface plasmon polariton propagated to the surface of the natural medium material, the power extraction efficiency can reach 10-20%, and the power extraction efficiency is far higher than that of the existing commonly-used slit extraction grating structure.
It should be noted that the nanopillar array extraction structure 4 includes a plurality of nanopillars 41 arranged at intervals. Specifically, as shown in fig. 3, each of the nanopillars 41 has an identical cylindrical structure, and thus the nanopillar array extraction structure 4 is integrated in an array by several nanopillars having the same size and shape. The material of each nano-pillar 41 is gold. Because gold is an approximately ideal metal material in the middle and far infrared bands, a strong local mode can be obtained near the gold nano-column, and efficient extraction on site is realized. In addition, the processes of cleavage, photoetching, film coating, electron beam photoetching, stripping and the like involved in the preparation of the gold nanorod array are mature photoelectronic device processing technologies, are widely applied to market products, and are stable in process and low in cost.
In the embodiment of the invention, the natural hyperbolic material layer 1 is made of calcite, hexagonal boron nitride, graphite, quartz and NaNO3Crystals or Al2O3And (4) crystals. Wherein, the calcite material is easily obtained in nature, is easy to artificially prepare and low in price, and has remarkable advantages compared with the existing radiation source based on the artificial lamellar hyperbolic metamaterialAnd (4) potential. Meanwhile, as shown in fig. 7, the material has a hyperbolic region in the far infrared and is low in loss, and is an excellent material suitable for preparing an infrared radiation source. Therefore, in the embodiment, the high-intensity free electron infrared radiation source integrated on the chip is prepared by combining the free electron threshold-free cerenkov radiation and the natural hyperbolic material calcite. Specifically, the natural hyperbolic material layer 1 can be obtained by cleavage and polishing of natural calcite crystals or artificially grown. In addition, the processes of cleavage and polishing of calcite crystals and the like are mature photoelectronic device processing technologies and are widely applied to market products.
It should be noted that calcite material is an optically anisotropic crystal material commonly found in nature, and the main component is calcium carbonate, which is a typical trigonal system uniaxial crystal with the optical axis direction perpendicular to the crystal (001) plane. Fig. 4 is a schematic diagram of a calcite crystal, in which the upper surface of the crystal sample is a (001) crystal plane, the direction indicated by a double-headed arrow is the direction of an optical axis, and the optical axis is perpendicular to the upper surface of the crystal sample. Wherein, the dielectric constants in the three directions of xyz can be represented as follows:
wherein epsilon⊥And ε∥Representing the dielectric constant of the material in the direction perpendicular and parallel to the optical axis, respectively. The distribution of the real part of dielectric constant of calcite in the mid and far infrared bands (40THz to 50THz) is shown in fig. 5 and 6. It can be seen that e is the frequency band from 42.1THz to 46THz⊥Is a negative value of epsilon∥Positive values. Selecting a 44THz frequency point as a target, the dielectric constants in two directions of calcite are respectively epsilon⊥＝-3.4005，ε∥2.1374. At this time, assuming the material is infinite in the x-direction, there is an electromagnetic modal dispersion relationship within the calcite material as follows:
where c is the speed of light and ω is the angular frequency corresponding to 44 THz. According to the formula, an equal frequency wave vector diagram (IFC) of the calcite material with 44THz frequency points can be drawn, and is shown in figure 7. Obviously, in this case, the iso-frequency wave vector diagram is a hyperbolic curve with an opening in the z direction, and is called a hyperbolic property, so calcite is called a natural hyperbolic material. In a hyperbolic interval, Cerenkov radiation excited by a free electron evanescent field does not have any electron velocity condition limit. Therefore, Cerenkov radiation supporting low-electron-energy excitation in the natural hyperbolic material, which is called non-threshold Cerenkov radiation, can be used for preparing on-chip integrated radiation devices. Since the hyperbolic region of calcite is located in the 42.1THz to 46THz frequency band, the device proposed in this embodiment is an integrated free electron light source in this frequency band.
According to the theory of thresholdless cerenkov radiation, the equivalent refractive index of phonon modes in calcite can be calculated by the following formula:
wherein v is0The value of the equivalent dielectric constant of each direction taken at 44THz for the electron velocity can be calculated when the kinetic energy of the excited free electrons is 1keV, i.e. the electron velocity is about 1.87 × 107At m/s, the equivalent refractive index of phonon excimer modes inside the material can be as high as about 25.75, which is much larger than that of a general dielectric material. The CR mode is limited to the inside of the calcite crystal and cannot radiate to the free space, which brings difficulty to the practical use of the device. Therefore, in order to extract CR in the film with high efficiency, the present embodiment performs extraction of an electromagnetic mode using a gold nanopillar array structure. The principle of extraction of CR mode by a single gold nanorod (Au nanodisk) is schematically illustrated in fig. 8, and the CR mode excited by free electrons inside Calcite crystal is essentially phonon polariton of Calcite (Calcite).
When CR propagates to the surface of calcite, it is bound inside the material due to the large refractive index difference between the material and the vacuum (Vaccum) environment. By arranging the gold nano-column with a proper size, a phonon excimer mode propagated to the surface of calcite can form a local resonance mode at the position of the nano-column, local enhancement of a radiation field is realized at the position of the nano-column, and large wave vector matching is realized, so that extraction from crystal phonon polaritons to a vacuum radiation mode is realized.
In the embodiment of the present invention, the thickness of the natural hyperbolic material layer 1 is less than or equal to 1mm, and may be, for example, 1 μm to 1 mm. The surface size may vary from 100 μm to 1cm depending on device requirements. As shown in fig. 2, the natural hyperbolic material layer 1 adopts calcite crystals, the upper and lower surfaces of the calcite crystals can be cleavage planes of any crystal plane of the crystals, and can also be polishing sections of non-crystal planes, and the surface should be as flat as possible so as to be more beneficial to the interaction of a free electron evanescent field with the natural hyperbolic material layer. The calcite has the main function that by utilizing the anisotropy and natural hyperbolic property of the calcite, threshold-free Cerenkov radiation is generated by coupling a free electron evanescent field, and then infrared radiation is generated. It should be noted that, regarding the arrangement position of the cerenkov infrared radiation source based on the natural hyperbolic material as shown in fig. 2, the vertical direction in the figure is the pointed vertical direction and the thickness direction of the natural hyperbolic material layer 1.
In the embodiment of the invention, the nano-pillar array extraction structures 4 are arranged in a square, hexagonal or random manner, so that efficient extraction of calcite with different frequencies in a CR mode can be realized. For example, a quad arrangement as shown in fig. 3. If the structure is arranged in a hexagonal shape, the space utilization rate can be further improved. If the radiation source is randomly arranged, the radiation source is arranged in a disordered way and is mainly used for wide spectrum extraction of radiation. Of course, the arrangement of the nanopillar array includes, but is not limited to, square arrangement, hexagonal arrangement, random arrangement, and the like, and may be specifically determined according to actual design requirements.
In alternative embodiments of the present invention, the diameter of the nano-pillars 41 is 10nm to 5 μm, and/or the distance between two adjacent nano-pillars 41 is 100nm to 20 μm. Therefore, through different diameters of the nano-columns and different arrangement periods, the radiation extraction of different target frequency points can be realized. In addition, the preparation of the nano-column array can be completed by electron beam lithography, gold deposition process, stripping process and the like, which belong to quite perfect and mature processing processes, so that the preparation cost is low, the time is fast, the effect is good, and the large-area integrated preparation and application of devices are facilitated.
In an embodiment of the present invention, the material of the on-chip free electron emission source is gold, molybdenum, platinum, graphene or carbon nanotube. The method for preparing the free electron emission source on the sheet by adopting the metals with high breakdown thresholds such as molybdenum and platinum belongs to the mature process technology, can prepare the free electron emission source on the surface of a calcite crystal by a micro-nano processing process, and has the advantages of stable process and low cost.
It should be noted that the shape of the on-chip electron source cathode 2 may be designed to be a needle point shape, a zigzag shape, a triangular shape or a conical shape. Therefore, the threshold value of an electric field emitted by electrons can be reduced, the beam spot of the emitted electron beam is reduced, the emission current is increased, the directional positioning emission of the electron beam is facilitated, and the device integration is facilitated.
The Cerenkov infrared radiation source based on the natural hyperbolic material is specifically described by combining the various embodiments. The embodiment of the invention provides a Cerenkov infrared radiation source based on a natural hyperbolic material, which comprises a natural hyperbolic material layer 1, an on-chip electron source cathode 2, an on-chip electron source anode 3 and a nano-column array extraction structure 4. Wherein the natural hyperbolic material layer 1 adopts calcite crystals, and the nano-column array extraction structure 4 adopts a gold nano-column array extraction structure. The radiation device generates infrared radiation by utilizing non-threshold Cerenkov radiation excited by free electrons flying in vacuum in calcite crystals, and is integrated with the existing mature on-chip electron source process to prepare a fully-integrated on-chip device.
Compared with artificial hyperbolic metamaterials, natural hyperbolic materials such as calcite and the like are mostly natural crystals, exist in a large amount in nature and are easy to prepare in a large amount manually, so that the preparation cost and the process complexity of the photoelectronic device based on the natural hyperbolic materials are greatly reduced, and meanwhile, the crystal materials are easy to grow and have good stability and few defects, so that the influence on the performance of the device caused by the processing process precision of the materials can be avoided to the greatest extent. Secondly, because calcite crystals do not contain metallic components, cerenkov radiation excited by free electrons therein propagates in the form of phonon polaritons, in contrast to artificial hyperbolic hyper-crystalsThe plasma interlayer coupling of the material has obviously lower loss, so that the corresponding device has higher radiation power, higher efficiency and less heat. Thirdly, the size of the naturally or artificially grown calcite crystal can easily reach the centimeter magnitude, and is increased by 10 compared with the artificial hyperbolic metamaterial with the hundred-micron magnitude3-4The method greatly improves the integration level and the space efficiency of related devices, and provides a possible scheme for the high-power array integrated free electron light source.
In conclusion, the invention applies a brand new physical mechanism, utilizes the low-cost natural hyperbolic material calcite to prepare the fully-integrated miniaturized on-chip mid-far infrared radiation source, has mature process and low price, can realize output in the micro watt level on a micron-millimeter level chip, realizes a scheme of a free electron radiation infrared light source, and solves the problems of high cost, complex process, poor stability and the like of the conventional free electron radiation source based on the artificial hyperbolic metamaterial. Meanwhile, the application frequency band of the on-chip CR device can be expanded to the middle and far infrared bands, a brand-new research idea and direction are provided for the integrated infrared radiation source, and the on-chip CR device has double meanings of physical theory and device application.
In addition, based on a natural medium material, phonon polaritons based on calcite are generated by radiation, and compared with the principle that metal layer plasmas of an artificial hyperbolic metamaterial are coupled layer by layer, the intrinsic loss is lower, so that the theoretical radiation power is improved by 1-2 orders of magnitude. Meanwhile, the novel gold nanorod array extraction structure is utilized to efficiently extract a large-wave vector CR mode in a calcite crystal, an infrared phonon polarization excimer mode in the crystal is extracted to a radiation mode in a free space, the function of an infrared radiation source is realized, the output power is higher, the extraction efficiency is higher by more than 20 times compared with that of an existing nano slit grating structure, and the total output power of the device can be higher by more than 2-3 orders of magnitude compared with that of an existing Cherenkov radiation device. In addition, the device is mainly based on natural crystal materials, so that the domain layout and the array are easy to realize, and the output optical power is expected to be further enhanced.
The free electron light source provided by the invention is described below, and the free electron light source described below and the cerenkov infrared radiation source based on the natural hyperbolic material described above can be correspondingly referred to each other.
The embodiment of the invention also provides a free electron light source which comprises the Cerenkov infrared radiation source based on the natural hyperbolic material in the embodiments. According to the arrangement, the on-chip free electron emission source generates stable free electron beams to excite infrared Cerenkov radiation in the natural hyperbolic material. The natural hyperbolic metamaterial is low in cost, easy to obtain and simple in preparation process, and has remarkable advantages compared with an artificial hyperbolic metamaterial. Meanwhile, as the natural hyperbolic material is easy to grow, good in stability and few in defects, the influence on the device performance caused by the material processing process precision can be avoided to the greatest extent. And based on natural medium materials, the intrinsic loss is lower, so that the corresponding device has higher radiation power, higher efficiency and less heat generation. In addition, based on natural crystal materials, territory and array are easy to realize, the integration level and the space efficiency of related devices are greatly improved, and a possible scheme is provided for a high-power array integrated free electron light source. The derivation process of the beneficial effect is substantially similar to the derivation process of the beneficial effect of the cerenkov infrared radiation source based on the natural hyperbolic material, and therefore, the details are not repeated herein.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A Cerenkov infrared radiation source based on natural hyperbolic material is characterized by comprising:
a layer of natural hyperbolic material;
and the on-chip free electron emission source is arranged on one side of the natural hyperbolic material layer and comprises an on-chip electron source cathode and an on-chip electron source anode.
2. The natural hyperbolic material-based cerenkov infrared radiation source of claim 1, further comprising a nanocolumn array extraction structure disposed on another side of the natural hyperbolic material layer for extracting cerenkov radiation generated within the natural hyperbolic material layer.
3. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 1, wherein the natural hyperbolic material layer is made of calcite, hexagonal boron nitride, graphite, quartz, NaNO3Crystals or Al2O3And (4) crystals.
4. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 1, characterized in that the thickness of the layer of natural hyperbolic material is less than or equal to 1 mm.
5. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 2, wherein the nanopillar array extraction structure comprises a plurality of nanopillars arranged at intervals, each nanopillar being made of gold.
6. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 1, wherein the nanopillar array extraction structures are in a tetragonal arrangement, hexagonal arrangement or random arrangement.
7. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 5, wherein the diameter of the nano-pillars is 10nm to 5 μm, and/or the distance between two adjacent nano-pillars is 100nm to 20 μm.
8. The Cerenkov infrared radiation source based on natural hyperbolic material of claim 1, wherein the material of the on-chip free electron emission source is gold, molybdenum, platinum, graphene or carbon nanotube.
9. The Cerenkov infrared radiation source based on natural hyperbolic material as claimed in claim 1, wherein the cathode of the on-chip electron source is in the shape of a needle point, a saw tooth, a triangle or a cone.
10. A free electron light source comprising a cerenkov infrared radiation source based on natural hyperbolic material as claimed in any one of claims 1-9.
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