Device for forming at least one focused beam in the near zone, from incident electromagnetic waves
The present disclosure concerns a device for forming at least one focused beam in a near zone, from an electromagnetic wave incident on said device. Such device is remarkable in that it comprises at least one layer of a dielectric material comprising at least partially a first element, said first element having a first refractive index value, said first element comprising at least partially a second element, said second element having a second refractive index value greater than said first index value, and wherein said second element comprises at least a base surface, defined with respect to an arrival direction of said electromagnetic wave, and wherein said at least a base surface comprises at least two opposite edge line segments whose shape and associated base angles between said at least a base surface and a lateral surface of said second element, in a vertical plane with respect to said at least a base surface, control a shape of said at least one focused beam.
1. A device comprising
a layer of dielectric material embedding a double-layer element comprising a core and, an outer shell, said outer shell having a first refractive index value, and said core having a second refractive index value greater than said first refractive index value, and wherein a focused beam is obtained from a combination of beams generated from an interference of parts of an incident electromagnetic wave on said device propagating through a base of said outer shell and a base of said core,
wherein said core comprises a base surface, defined with respect to an arrival direction of said electromagnetic wave, said base surface comprising opposite edge lines, at least one of the opposite edge lines being a line whose shape and associated base angles between said base surface and a lateral surface of said core control a shape of said focused beam.
2. The device according to claim 1 , wherein said core has a geometric shape selected from the group consisting of a cylinder, a prism, and a cone.
3. The device according to claim 2 , wherein said geometric shape is oblique and/or truncated and/or comprises a rounded top surface.
4. The device according to claim 1 , wherein a distance between the opposite edge lines has a minimum length of at least λ 2 /2, where λ 2 is a wavelength of said electromagnetic wave in a material of said core.
5. The device according to claim 1 , wherein at least one of the opposite edge lines has a length of at least λ 2 , where λ 2 is a wavelength of said electromagnetic wave in a material of said core.
6. The device according to claim 1 , wherein said layer of dielectric material has a third refractive index value which is equal to said second refractive index value.
7. The device according to claim 1 , wherein said outer shell comprises a first base surface, defined with respect to an arrival direction of said electromagnetic wave, and a first lateral surface connected with said layer of dielectric material, and wherein a minimum distance between each of the edge line of an edge of said base surface, and said first lateral surface is equal to at least λ 2 , where λ 2 is a wavelength of said electromagnetic wave in said core.
8. The device according to claim 1 , wherein said outer shell has a geometric shape selected from the group consisting of a cylinder, a prism, and a cone.
9. The device according to claim 1 , wherein the device further comprises a layer forming a substrate abutting said layer of dielectric material.
10. The device according to claim 9 , wherein the device further comprises a layer forming a superstrate, said layer of dielectric material being located between said substrate and said superstrate.
11. The device according to claim 10 , wherein said substrate and said superstrate are made of the same dielectric material as said layer of dielectric material.
12. The device according to claim 1 , wherein said layer of dielectric material is selected from the group consisting of a glass, a plastic, and a polymer material.
13. The device according to claim 10 , wherein a material of said superstrate is selected from the group consisting of a glass, a plastic, a polymer material, a liquid, and a gas.
14. The device according to claim 1 , wherein said outer shell is a cavity formed in said layer of dielectric material.
15. The device according to claim 10 , wherein said outer shell is a cavity formed in said layer of dielectric material, and wherein when said superstrate is a gas or a liquid, said cavity is filled with a same gas or liquid.
16. The device according to claim 1 , wherein a size of said outer shell further controls the shape of said focused beam.