Device for controlling the phase of an optical wavefront having juxtaposed metal-multidielectric-metal structures to induce a local shift

摘要

According to one aspect, the invention relates to a device (20, 50) for controlling the phase of an incident optical wavefront of wavelength comprised in a spectral band of given use, comprising a substrate (21) that is at least partially transparent in said spectral band and a set of strips (22i, 23i, 24i) arranged substantially perpendicularly to the surface of the substrate, characterized in that: said set of strips comprises an alternation of juxtaposed strips respectively made of a metal (22i), of a first dielectric (23i) and of at least one second dielectric (24i) different from the first dielectric, such as to form juxtaposed metal/multi dielectric/metal (MmultiDM) structures (Si) of subwavelength widths (wi), each structure forming a cavity having one or more propagation modes—the respective thicknesses of the strips made of the first dielectric and of the second dielectric(s) are adjusted in each of said MmultiDM structures to induce a local shift (ΔΦi) in the phase of the wavefront, the local phase shift being dependent on the effective index of the mode(s) able to propagate in said cavity.

主权项

1. A device for controlling the phase of an incident optical wavefront having a wavelength in a given spectral band of use, comprising:
a substrate that is at least partially transparent in said spectral band and a set of blades arranged substantially at right angles to the surface of the substrate, wherein: said set of blades comprises an alternation of juxtaposed blades, respectively made of metal material, of a first dielectric material and of at least one second dielectric material different from the first dielectric material, so as to form juxtaposed metal-multidielectric-metal (MmultiDM) structures, of sub-wavelength widths, each structure forming a cavity exhibiting one or more propagation modes, and the respective thicknesses of the blades made of a first dielectric material and of second dielectric material(s) are adjusted in each of said MmultiDM structures to induce a local shift of the phase of the wavefront, the local phase shift being dependent on the effective index of the mode or modes able to be propagated in said cavity.