Ultra-thin, planar, plasmonic metadevices
AssigneePurdue Research Foundation
InventorsVladimir Shalaev, Alexander Kildishev, Xingjie Ni, Satoshi Ishii
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Abstract
An ultra-thin planar device is used for arbitrary waveform formation on a micrometer scale, regardless of the incident light's polarization. Patterned perforations are made in a 30 nm-thick metal film, creating discrete phase shifts and forming a desired wavefront of cross-polarized, scattered light. The signal-to-noise ratio of these devices is at least one order of magnitude higher than current metallic nano-antenna designs. The focal length of a lens built on such principle can also be adjusted by changing the wavelength of the incident light. All proposed embodiments can be embedded, for example, on a chip or at the end of an optical fiber.
Claims20
A planar plasmonic device for arbitrary waveform formation, comprising:
- a plurality of nanovoids perforated in a subwavelength-thick metal film, wherein said nanovoids form a pattern, and wherein a shape of each nanovoid provides a change of phase and magnitude of an incoming radiation due to plasmonic resonance of the radiation coupled to this nanovoid, the shape of each nanovoid defines individual resonance characteristics, thus providing a given phase front of outcoming radiation, which is combined from portions of radiation exiting all nanovoids in said film.
A method for converting a phase and an intensity of incoming radiation for arbitrary waveform formation, comprising:
- perforating a pattern of a plurality of nanovoids in a subwavelength-thick metal film, wherein said pattern comprises nanovoids of varying shapes corresponding to desired resonance characteristics that incoming radiation experiences during propagation through said nanovoid;
- inputting radiation on said metal film with said pattern of nanovoids, wherein the radiation propagates through each individual nanovoid due to a plasmonic resonance within and along each nanovoid;
- and producing an outcoming desired phase front of said radiation, wherein the resonance characteristics of each specifically-shaped nanovoid converts the phase and the magnitude of said incoming radiation into a desired outcoming phase front.
Dependencies are inferred from the claim text.