A device configured to radiate a focused electromagnetic beam in a dielectric host medium when an incoming electromagnetic wave generated by a light source illuminates a first face of the device, wherein the host medium surrounds the device and has a first refractive index n 1, wherein the device comprises: a first material having a second refractive index n 2 and having a first width W 1 along an X-axis that is a direction of extension of the first face; and a second material in contact with the first material and having a third refractive index n3, wherein the second material has a second width W 2 along the X-axis, where n1<n3<n2, and where W 1 + W 2 is greater than an equivalent wavelength λ in the host medium of the incoming electromagnetic wave radiated by the light source, the first material and the second material extending along a Z-axis that is a direction orthogonal to the first face from the first face up to a radiating face of each material, opposite to the first face, the first material and the second material having respectively a first height H1 and a second height H2 along the Z-axis, where | H 2 - H 1| ≤ λ /4; wherein the device comprises, when the device is in contact with the dielectric host medium and when the incoming electromagnetic wave illuminates the first face: a first contact area (100e1) between the dielectric host medium and the first material; a second contact area (100e2) between the first material and the second material; and a third contact area (100e3) between the second material and the dielectric host medium, wherein the focused electromagnetic beam results from a combination of at least two beams among a first jet beam radiated in a near field zone by the first contact area, a second jet beam radiated in the near field zone by the second contact area, and a third jet beam radiated in the near field zone by the third contact area when the incoming electromagnetic wave illuminates the first face, wherein a direction of propagation of the focused electromagnetic beam is tilted with respect to a direction of propagation of the incoming electromagnetic wave. a first material having a second refractive index n 2 and having a first width W 1 along an X-axis that is a direction of extension of the first face; and a second material in contact with the first material and having a third refractive index n3, wherein the second material has a second width W 2 along the X-axis, where n1<n3<n2, and where W 1 + W 2 is greater than an equivalent wavelength λ in the host medium of the incoming electromagnetic wave radiated by the light source, the first material and the second material extending along a Z-axis that is a direction orthogonal to the first face from the first face up to a radiating face of each material, opposite to the first face, the first material and the second material having respectively a first height H1 and a second height H2 along the Z-axis, where | H 2 - H 1| ≤ λ /4; wherein the device comprises, when the device is in contact with the dielectric host medium and when the incoming electromagnetic wave illuminates the first face: a first contact area (100e1) between the dielectric host medium and the first material; a second contact area (100e2) between the first material and the second material; and a third contact area (100e3) between the second material and the dielectric host medium, wherein the focused electromagnetic beam results from a combination of at least two beams among a first jet beam radiated in a near field zone by the first contact area, a second jet beam radiated in the near field zone by the second contact area, and a third jet beam radiated in the near field zone by the third contact area when the incoming electromagnetic wave illuminates the first face, wherein a direction of propagation of the focused electromagnetic beam is tilted with respect to a direction of propagation of the incoming electromagnetic wave. a first contact area (100e1) between the dielectric host medium and the first material; a second contact area (100e2) between the first material and the second material; and a third contact area (100e3) between the second material and the dielectric host medium, wherein the focused electromagnetic beam results from a combination of at least two beams among a first jet beam radiated in a near field zone by the first contact area, a second jet beam radiated in the near field zone by the second contact area, and a third jet beam radiated in the near field zone by the third contact area when the incoming electromagnetic wave illuminates the first face, wherein a direction of propagation of the focused electromagnetic beam is tilted with respect to a direction of propagation of the incoming electromagnetic wave.