# US 2018/0321518 A1 · Systems and Methods for Implementing Electrically Tunable Metasurfaces > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0321518 A1 - Document ID: US20180321518A1 - Status: Published application - Kind: A1 - Application number: 15/967,445 - Filed: 2018-04-30 - Published: 2018-11-08 - Earliest claimed: 2014-03-06 - Assignees: California Institute of Technology - Applicants: California Institute of Technology - Inventors: Harry A. Atwater - Web page: https://patentgrep.com/patent/US20180321518A1 ## CPC - G02F 1/0018: {Electro-optical materials} - G02B 1/002: {made of materials engineered to provide properties not available in nature, e.g. metamaterials} - G02B 26/02: for controlling the intensity of light {(G02B26/004 takes precedence)} - G02F 1/0121: {Operation of devices; Circuit arrangements, not otherwise provided for in this subclass} - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - G02F 2202/30: Metamaterials - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract Systems and methods in accordance with embodiments of the invention implement electrically tunable metasurfaces. In one embodiment, an electrically tunable metasurface reflectarray includes: a mirrored surface; a conductive layer; a dielectric layer; where the conductive layer and the dielectric layer are in direct contact, and thereby define a conductor-dielectric interface; a plurality of subwavelength antenna elements; and an electrical power source configured to establish a potential difference between at least one subwavelength antenna element and the mirrored surface; where a potential difference between a subwavelength antenna element and the mirrored surface applies an electric field to a corresponding region of the electrically tunable metasurface reflectarray; where any applied electric fields in conjunction with the geometry and the material composition of each of the subwavelength antenna elements, the conductive layer, and the dielectric layer, enable the electrically tunable metasurface reflectarray to measurably augment the propagation characteristics of incident electromagnetic waves. ## Claims ### Claim 1 An electrically tunable metasurface reflectarray comprising: a mirrored surface; a conductive layer; a dielectric layer; wherein the conductive layer and the dielectric layer are in direct contact, and thereby define a conductor-dielectric interface; a plurality of subwavelength antenna elements; and an electrical power source configured to establish a potential difference between at least one subwavelength antenna element and the mirrored surface; wherein a potential difference between a subwavelength antenna element and the mirrored surface applies an electric field to a corresponding region of the electrically tunable metasurface reflectarray; wherein any applied electric fields in conjunction with the geometry and the material composition of each of the subwavelength antenna elements, the conductive layer, and the dielectric layer, enable the electrically tunable metasurface reflectarray to measurably augment the propagation characteristics of incident electromagnetic waves. ### Claim 2 (depends on 1) The electrically tunable metasurface reflectarray of claim 1 further comprising a second electrical power source configured to establish a second potential difference between at least one other subwavelength antenna element and the mirrored surface. ### Claim 3 (depends on 1) The electrically tunable metasurface reflectarray of claim 1, wherein the electrical power source is configured to establish a plurality of potential differences between a plurality of subwavelength antenna elements and the mirrored surface. ### Claim 4 (depends on 3) The electrically tunable metasurface reflectarray of claim 3, wherein any applied electric fields in conjunction with the geometry and the material composition of each of the subwavelength antenna elements, the conductive layer, and the dielectric layer, enable the electrically tunable metasurface reflectarray to measurably augment the propagation characteristics of incident electromagnetic waves falling within at least some portion of the electromagnetic spectrum characterized by wavelengths of less than 10 μm. ### Claim 6 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein the at least some portion of the electromagnetic spectrum is characterized by electromagnetic waves having wavelengths less than or equal to wavelengths approximately corresponding with those of near infrared electromagnetic waves. ### Claim 7 (depends on 6) The electrically tunable metasurface reflectarray of claim 6, wherein when a region of the electrically tunable metasurface is exposed to an electric field, reflected incident electromagnetic waves falling within the at least some portion of the electromagnetic spectrum exhibit a phase shift based on the magnitude of the applied electric field. ### Claim 8 (depends on 6) The electrically tunable metasurface reflectarray of claim 6, wherein the at least some portion of the electromagnetic spectrum is characterized by electromagnetic waves having wavelengths approximately corresponding with those of near infrared electromagnetic waves. ### Claim 9 (depends on 6) The electrically tunable metasurface reflectarray of claim 6, wherein the at least some portion of the electromagnetic spectrum is characterized by electromagnetic waves having wavelengths less than or equal to wavelengths approximately corresponding with those of visible light. ### Claim 10 (depends on 9) The electrically tunable metasurface reflectarray of claim 9, wherein the at least some portion of the electromagnetic spectrum is characterized by electromagnetic waves having wavelengths approximately corresponding with those of visible light. ### Claim 11 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein: the conductive layer comprises one of: a nitride based material; silver; copper; gold; aluminum; an alkali metal; an alloy; a transparent conducting alloy; and graphene. ### Claim 12 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein the conductive layer comprises indium tin oxide. ### Claim 13 (depends on 12) The electrically tunable metasurface reflectarray of claim 12, wherein the dielectric layer comprises a dielectric oxide. ### Claim 14 (depends on 13) The electrically tunable metasurface reflectarray of claim 13, wherein the dielectric layer comprises aluminum oxide. ### Claim 15 (depends on 14) The electrically tunable metasurface reflectarray of claim 14, wherein: the mirrored surface comprises gold; and at least one of the plurality of subwavelength antenna elements comprises gold. ### Claim 16 (depends on 15) The electrically tunable metasurface reflectarray of claim 15, wherein when a region of the electrically tunable metasurface reflectarray is exposed to an electric field, the charge carrier concentration at the conductor-dielectric interface within that region is altered based on the magnitude of the applied electric field, and this alteration causes a phase shift in reflected incident electromagnetic waves falling within the at least some portion of the electromagnetic spectrum. ### Claim 17 (depends on 16) The electrically tunable metasurface reflectarray of claim 16, wherein a variation in charge carrier concentration from 1×1019 cm−3 to 1×1021 cm−3 is sufficient to shift the phase of reflected incident electromagnetic waves falling within the at least some portion of the electromagnetic spectrum by at least 2π. ### Claim 18 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein at least one of the plurality of subwavelength antenna elements conforms to a rod-shaped geometry. ### Claim 19 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein at least one of the plurality of subwavelength antenna elements conforms to a V-shaped geometry. ### Claim 20 (depends on 4) The electrically tunable metasurface reflectarray of claim 4, wherein at least one of the plurality of subwavelength antenna elements conforms to a split ring geometry.