A structure for achieving uniform electromagnetic wave energy enhancement in subwavelength air regions

Abstract

This invention relates to the fields of biosensing, micro / nano manipulation, photoelectric signal detection, and subwavelength focusing. Existing structures for enhancing electromagnetic wave energy still have limitations such as non-uniform enhancement factor, non-air regions for energy enhancement, and difficulty in achieving subwavelength energy enhancement. This invention discloses a structure that can uniformly enhance electromagnetic wave energy in the air region of the subwavelength range. This structure is a waveguide structure filled with a near-zero refractive index medium, incorporating medium-air-medium columnar impurities. When external electromagnetic waves are incident on this waveguide structure, a highly uniform local electric field enhancement and electromagnetic wave energy enhancement effect are generated in the air columnar region. The enhanced electromagnetic wave energy exhibits high uniformity and better stability. By achieving electromagnetic wave manipulation within the subwavelength range, it can be applied to bioimaging, biosensing, and focusing of related electromagnetic devices.

Description

Technical Field

[0001] This invention relates to fields such as biosensing, micro-nano manipulation, photoelectric signal detection, and subwavelength focusing; more specifically, it relates to a structure for achieving uniform electromagnetic wave energy enhancement in the subwavelength air region. Background Technology

[0002] Achieving localized electromagnetic wave energy enhancement can improve the sensitivity of photoelectric signal detection and various electromagnetic sensors. For example, optical nanoantennas can achieve localized electromagnetic wave energy enhancement. Combining optical nanoantennas with photodetectors can not only improve the signal-to-noise ratio of the detector but also increase the sensitivity by at least one order of magnitude. Furthermore, special metamaterials can also achieve localized electromagnetic wave energy enhancement. Using metamaterials for surface-enhanced Raman scattering can achieve single-molecule detection sensitivity in biosensing technology, which is of great significance for disease diagnosis and environmental monitoring. However, existing structures for achieving electromagnetic wave energy enhancement still have limitations such as non-uniform enhancement factor, non-air regions for energy enhancement, and difficulty in achieving electromagnetic wave energy enhancement in subwavelength regions. Currently, a structure that can achieve uniform electromagnetic wave energy enhancement in subwavelength air regions is still lacking. Summary of the Invention

[0003] To address the shortcomings of the prior art, this invention proposes a structure for achieving uniform electromagnetic wave energy enhancement in a subwavelength air region, thereby achieving uniform electromagnetic wave energy enhancement within a three-dimensional subwavelength air column.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A structure for achieving uniform electromagnetic wave energy enhancement in a subwavelength air region includes a three-dimensional electromagnetic waveguide energy enhancement structure and a dielectric pillar placed inside the three-dimensional electromagnetic waveguide energy enhancement structure. The dielectric pillar is filled with a dielectric material and is divided into two parts by an air pillar in the middle. The three-dimensional electromagnetic waveguide energy enhancement structure is filled with a near-zero refractive index dielectric material. When an electromagnetic wave enters the three-dimensional electromagnetic waveguide energy enhancement structure, uniformly enhanced electromagnetic wave energy is generated in the air pillar region of the dielectric pillar.

[0006] Furthermore, the three-dimensional electromagnetic waveguide energy enhancement structure includes an upper boundary surface, a lower boundary surface, two side boundary surfaces, and a rear boundary surface. The upper and lower boundary surfaces are parallel to each other, the two side boundary surfaces are parallel to each other, and the upper, lower, and two side boundary surfaces are all perpendicular to the rear boundary surface. The upper, lower, and two side boundary surfaces are located on the same side of the rear boundary surface.

[0007] Furthermore, the dielectric constant ε of the near-zero refractive index medium is ≤0.1, and the magnetic permeability μ is ≤0.1.

[0008] Furthermore, the refractive index of the medium filling the dielectric column is greater than 1.

[0009] Furthermore, the length of the air column is in the subwavelength range.

[0010] In summary, the invention has the following beneficial effects:

[0011] In use, when electromagnetic waves are incident along the x-direction onto the structure of this invention that achieves uniform electromagnetic wave energy enhancement, uniform electromagnetic wave energy enhancement is achieved in the subwavelength air region of the columnar impurities. The size of the region where electromagnetic wave energy is enhanced can reach the subwavelength level, that is, subwavelength-sized electromagnetic wave energy focusing is obtained. By achieving electromagnetic wave manipulation within the subwavelength range, it can be applied to bioimaging, biosensing, and focusing of related electromagnetic devices. The enhanced electromagnetic wave energy has high uniformity and better stability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the electromagnetic wave energy enhancement structure designed in this invention.

[0013] Figure 2 yes Figure 1 The xy-plane diagram of the structure that enhances electromagnetic wave energy.

[0014] Figure 3 This is a numerical simulation of the electromagnetic wave energy distribution of the invented electromagnetic wave energy enhancement structure in the xy plane.

[0015] Figure 4 This is a numerical simulation of the electromagnetic wave energy distribution of the invented electromagnetic wave energy enhancement structure in the xz plane.

[0016] (1) is a near-zero refractive index medium, (2) is a medium column, (3) is an air column, (4) is the upper boundary, (5) is the lower boundary, (6) is the side boundary, and (7) is the rear boundary. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and examples.

[0018] It should be noted that, for ease of description, the descriptions of direction in the following text are consistent with the directions in the accompanying drawings, but they do not limit the structure of the present invention.

[0019] like Figures 1-4As shown, this invention discloses a structure for achieving uniform electromagnetic wave energy enhancement in the subwavelength air region. This structure, which achieves uniform electromagnetic wave energy enhancement in the subwavelength air region of columnar impurities (i.e., an air column), includes a three-dimensional electromagnetic waveguide energy enhancement structure and a dielectric column 2 placed inside the three-dimensional electromagnetic waveguide energy enhancement structure. The dielectric column 2 is filled with a medium with a refractive index greater than 1. An air column 3 divides the dielectric column 2 into two parts in the middle, with the upper and lower parts filled with the same medium. The length and position of the air column 3 can be adjusted as needed within the subwavelength range, effectively dividing the dielectric column 2 into two parts. A near-zero refractive index medium 1 is filled in the three-dimensional electromagnetic waveguide energy enhancement structure. The near-zero refractive index medium has a dielectric constant ε ≤ 0.1 and a permeability μ ≤ 0.1. When an electromagnetic wave enters the three-dimensional electromagnetic waveguide energy enhancement structure, uniformly enhanced electromagnetic wave energy is generated in the air column 3 region of the dielectric column 2.

[0020] The three-dimensional electromagnetic waveguide energy enhancement structure also includes an upper boundary surface 4, a lower boundary surface 5, two side boundary surfaces 6, and a rear boundary surface 7. One set of mutually parallel boundaries is the upper boundary surface 4 and the lower boundary surface 5, and the other set of mutually parallel boundaries is the side boundary surface 6. Both sets of parallel boundary surfaces are perpendicular to the rear boundary surface 7. The upper boundary surface 4, the lower boundary surface 5, and the two side boundary surfaces 6 are located on the same side of the rear boundary surface 7.

[0021] Example: In this example, the operating wavelength of the electromagnetic wave is designed to be λ0 = 7.5cm. Figure 1 The dimensional parameters of the electromagnetic wave energy enhancement structure described in the paper are selected as follows: the length of the waveguide along the x-direction is λ0, the width along the y-direction is λ0, and the height along the z-direction is λ0; the radius of the air column 3 is set to 0.05λ0 and the height is set to 0.1λ0; the refractive index of the dielectric column 2 is set to 10, the radius is set to 0.05λ0, and the height is set to 0.45λ0. Figure 3 yes Figure 1 The electromagnetic wave energy distribution diagram of the corresponding electromagnetic wave energy enhancement structure in the xy plane is shown in the numerical simulation. In the simulation settings, the electromagnetic wave energy is enhanced in the air column 3 region at the center of the columnar structure. Figure 4 yes Figure 1 The corresponding electromagnetic wave energy enhancement structure is shown in the numerical simulation electromagnetic wave energy distribution diagram in the xz plane. The simulation results show that the energy density time-averaged enhancement factor reaches about 300 times.

[0022] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A structure for achieving uniform electromagnetic wave energy enhancement in a subwavelength air region, characterized in that: The structure includes a three-dimensional electromagnetic waveguide energy enhancement structure and a dielectric column (2) placed inside the three-dimensional electromagnetic waveguide energy enhancement structure. The dielectric column (2) is filled with a dielectric material, and the dielectric column (2) is divided into two parts by an air column (3) in the middle. The three-dimensional electromagnetic waveguide energy enhancement structure is filled with a near-zero refractive index dielectric (1). When an electromagnetic wave enters the three-dimensional electromagnetic waveguide energy enhancement structure, a uniformly enhanced electromagnetic wave energy is generated in the air column (3) region of the dielectric column (2). The refractive index of the dielectric material filled in the dielectric column (2) is greater than 1, and the length of the air column (3) is in the subwavelength range.

2. The electromagnetic wave energy enhancement structure according to claim 1, characterized in that: The three-dimensional electromagnetic waveguide energy enhancement structure includes an upper boundary surface (4), a lower boundary surface (5), two side boundary surfaces (6) and a rear boundary surface (7). The upper boundary surface (4) and the lower boundary surface (5) are parallel to each other, the two side boundary surfaces (6) are parallel to each other, and the upper boundary surface (4), the lower boundary surface (5) and the two side boundary surfaces (6) are all perpendicular to the rear boundary surface (7). The upper boundary surface (4), the lower boundary surface (5) and the two side boundary surfaces (6) are located on the same side of the rear boundary surface (7).

3. The electromagnetic wave energy enhancement structure according to claim 1, characterized in that: The dielectric constant of the near-zero refractive index medium (1) ε ≤0.1, and permeability μ ≤0.1.

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