Elwha LLC

Lumotive, LLC

Erik Edward Josberger

Gleb M Akselrod

Mark C Weidman

Prasad Padmanabha Iyer

Yizhak Sabba

Tyler Williamson

Lie “Larry” Zhao

Laura Maria Pulido Mancera

Linda Gail Conway

A device may include a dielectric substrate layer with an array of multicoated elongated metal rails extending from the dielectric substrate parallel to one another and spaced from one another to form channels therebetween. The dimensions of the multicoated elongated metal rails and the channels therebetween may be subwavelength with respect to an operational bandwidth. In some examples, each multicoated elongated metal rail is formed with a copper core coated with an optically reflective silver coating followed by a passivation coating. In various examples, a conductive barrier material separates each multicoated elongated metal rail from an underlying dielectric substrate layer. A tunable dielectric material that has a tunable refractive index, such as liquid crystal, is positioned within the channels between adjacent multicoated elongated metal rails.

Multicoated tunable optical devices

According to various embodiments, a tunable optical device comprises a tunable optical metasurface on a substrate with an integrated driver circuit. In some embodiments, the tunable optical device includes a photon shield layer to prevent optical radiation from disrupting operation of the driver circuit. In some embodiments, the tunable optical device includes a diagnostic circuit to detect and disable defective optical structures of the metasurface. In some embodiments, the tunable optical device includes an integrated heater circuit that maintains a liquid crystal of the metasurface above a minimum operating temperature. In some embodiments, the tunable optical device includes an integrated lidar sequencing controller, a steering pattern subcircuit, and a photodetector circuit.

Tunable optical devices with integrated active switch-matrix driver circuits

A metasurface may include a substrate layer and a two-dimensional array of metallic optical pillars arranged in rows and columns. A tunable dielectric material with a tunable refractive index is positioned between row-adjacent optical resonators. A two-dimensional active-matrix driver includes integrated driver routing layer(s), capacitor layer(s), and/or transistor layer(s). The driver routing layers enable row and column addressing of the two-dimensional array of metallic pillars via a row conductor for each row of metallic pillars and a column conductor for each column of metallic pillars. A transistor layer includes transistor devices connected to and configured to be selectively driven by the row and column conductors. The capacitor layer includes a plurality of storage capacitors. Each metallic pillar is connected in parallel to one of the storage capacitors in the capacitor layer and one of the transistor devices in the transistor layer.

Two-dimensional metasurfaces with integrated capacitors and active-matrix driver routing

In various embodiments, a tunable optical surface includes a dielectric substrate layer with an array of elongated metal rails extending from the dielectric substrate parallel to one another and spaced from one another to form channels therebetween. The channels are etched deeper into the dielectric substrate to form extended-depth channels. The depth of each extended-depth channel is greater than the height of adjacent elongated metal rails. The dimensions of the elongated metal rails and the extended-depth channels therebetween may be subwavelength with respect to an operational bandwidth. A tunable dielectric material that has a tunable refractive index, such as liquid crystal, is positioned within the extended-depth channels between adjacent elongated metal rails.

Tunable optical devices with extended-depth tunable dielectric cavities

Subwavelength conducting particles can be arranged on conducting surfaces to provide arbitrary thermal emissivity spectra. For example, a thermal emissivity spectrum can be tailored to suppress a thermal signature of an object without sacrificing radiative cooling efficiency.

Thermal signature control structures

Integrated driver and heat control circuitry in tunable optical devices

Integrated driver and self-test control circuitry in tunable optical devices

According to various embodiments, a cover is sealed over a metasurface on a substrate to create a sealed chamber. Liquid crystal, or another tunable refractive index dielectric material, is positioned within the sealed chamber around optical structures of the metasurface before or after the cover is sealed. For example, the liquid crystal may be injected through small vias or holes to fill a sealed chamber. In some embodiments, a glass cover is shaped or patterned with photoresist to protrude into the sealed chamber to reduce the thickness of the liquid crystal used to fill the sealed chamber. A driver to control the metasurface may be, for example, integrated within the substrate, be attached to exposed bond pads of the metasurface, and/or be embodied as a control layer connected to the metasurface through the substrate by through-substrate vias (TSVs).

Tunable optical device configurations and packaging

According to various embodiments, a tunable optical metasurface includes an array of elongated resonator rails arranged parallel to one another. Liquid crystal is positioned within an optical field region between adjacent resonator rails. A controller can selectively apply a voltage differential pattern to the elongated resonator rails to adjust a phase response thereof. According to various embodiments, a cross-backplane reflector is utilized that allows for mid-array routing or edge-array routing of electrical connections between the controller and the resonator rails. The cross-backplane reflector comprises a plurality of elongated optical reflectors extending parallel to one another and perpendicular to the array of resonator rails. An optically transmissive (e.g., transparent) dielectric may electrically separate the resonator rails from the optical reflectors. A pattern of vias formed therein facilitates electrical connections between the optical reflectors and the resonator rails.

Liquid crystal metasurfaces with cross-backplane optical reflectors

The disclosure provides a method for fabricating a metallic optical metasurface having an array of hologram elements. The method includes forming a first copper layer protected with a conducting or dielectric barrier layer over a backplane structure by a damascene process. The first copper layer comprises a plurality of nano-gaps vertically extending from the backplane structure. The plurality of nano-gaps is filled with a dielectric material. The method also includes removing the dielectric material and a portion of the conducting or dielectric barrier layer to expose the portions in the nano-gaps of the first copper layer. The method may further include depositing a dielectric coating layer over the top portion and exposed side portions of the first copper layer to form a protected first copper layer, and filling the gaps with an electrically-tunable dielectric material that has an electrically-tunable refractive index.

Fabrication of metallic optical metasurfaces

The method is provided for fabricating an optical metasurface. The method may include depositing a conductive layer over a holographic region of a wafer and depositing a dielectric layer over the conducting layer. The method may also include patterning a hard mask on the dielectric layer. The method may further include etching the dielectric layer to form a plurality of dielectric pillars with a plurality of nano-scale gaps between the pillars.

Fabrication of optical metasurfaces

A 2D hologram system with a matrix addressing scheme is provided. The system may include a 2D array of sub-wavelength hologram elements integrated with a refractive index tunable core material on a wafer substrate. The system may also include a matrix addressing scheme coupled to the 2D array of sub-wavelength hologram elements and configured to independently control each of the sub-wavelength hologram elements by applying a voltage.

Control circuitry for 2D optical metasurfaces

Embodiments include a LIDAR scanning system. A laser is configured to emit pulses of light. A transmit reconfigurable-metasurface is configured to reflect an incident pulse of light as an illumination beam pointing at a field of view. This pointing is responsive to a first holographic beam steering pattern implemented in the transmit reconfigurable-metasurface. A receive reconfigurable-metasurface is configured to reflect a return of the illumination beam to an optical detector. This pointing is responsive to a second holographic beam steering pattern implemented in the receiving reconfigurable-metasurface. An optical detector includes an array of detector pixels. Each detector pixel includes (i) a photodetector configured to detect light in the return of the illumination beam and (ii) a timing circuit configured to determine a time of flight of the detected light. The optical detector is also configured to output a detection signal indicative of the detected light and the time of flight.

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Seattle, WA, United States of America

Erik Edward Josberger