Patent attributes
A device includes a host medium having a first refractive index value; a first layer comprising a first dielectric material having a second refractive index value, wherein the second refractive index value is greater than the first refractive index value, and wherein the first layer comprises a first step structure at a boundary between the first layer and the host medium; and a second layer comprising a second dielectric material and comprising a second step structure, the second layer having a third refractive index value higher than the first refractive index value of the host medium, wherein the second step structure is stacked on the first step structure, and, in response to an incident electromagnetic wave reaching the device, a first nanojet beam generated by the first step structure and a second nanojet beam generated by the second step structure are combined and focused around a first focusing point.