An all-optical Diffractive Deep Neural Network (D.sup.2NN) architecture learns to implement various functions or tasks after deep learning-based design of the passive diffractive or reflective substrate layers that work collectively to perform the desired function or task. This architecture was successfully confirmed experimentally by creating 3D-printed D.sup.2NNs that learned to implement handwritten classifications and lens function at the terahertz spectrum. This all-optical deep learning framework can perform, at the speed of light, various complex functions and tasks that computer-based neural networks can implement, and will find applications in all-optical image analysis, feature detection and object classification, also enabling new camera designs and optical components that can learn to perform unique tasks using D.sup.2NNs. In alternative embodiments, the all-optical D.sup.2NN is used as a front-end in conjunction with a trained, digital neural network back-end.

A device for producing a subwavelength hologram. The device comprises a metasurface layer attached to a substrate. The metasurface layer includes an array of plasmonic antennas that simultaneously encode both wavelength and phase information of light directed through the array to produce a hologram. The wavelength is determined by the size of the antennas, and the phase is determined by the orientation of the antennas.

Systems and methods are described herein for an optical beam-steering device that includes an optical transmitter and/or receiver to transmit and/or receive optical radiation from an optically reflective surface. An array of adjustable dielectric resonator elements is arranged on the surface with inter-element spacings less than an optical operating wavelength. A controller applies a pattern of voltage differentials to the adjustable dielectric resonator elements. The pattern of voltage differentials corresponds to a sub-wavelength reflection phase pattern for reflecting the optical electromagnetic radiation. One embodiment of a dielectric resonator element includes first and second dielectric members extending from the surface. The dielectric resonator elements are spaced from one another to form a gap or channel therebetween. A voltage-controlled adjustable refractive index material is disposed within the gap.

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.

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.

A hologram system may include a hologram chip comprising a wafer substrate having a first plurality of conductive pads on a hologram surface region connected to a second plurality of conductive pads on an interconnect surface region. The hologram chip may also include an array of sub-wavelength hologram elements integrated with a refractive index tunable core material on the hologram region of the wafer substrate. The hologram system may also include a control circuit chip having a third plurality of conductive pads connected to the second plurality of conductive pads on the interconnect region of the wafer substrate. The interconnect region is on the same side of the wafer substrate as the hologram region. The first plurality of conductive pads is directly connected to the array of sub-wavelength hologram elements.

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.

Systems and methods are described herein for an optical beam-steering device that includes an optical transmitter and/or receiver to transmit and/or receive optical radiation from an optically reflective surface. An array of adjustable dielectric resonator elements is arranged on the surface with inter-element spacings less than an optical operating wavelength. A controller applies a pattern of voltage differentials to the adjustable dielectric resonator elements. The pattern of voltage differentials corresponds to a sub-wavelength reflection phase pattern for reflecting the optical electromagnetic radiation. One embodiment of a dielectric resonator element includes first and second dielectric members extending from the surface. The dielectric resonator elements are spaced from one another to form a gap or channel therebetween. A voltage-controlled adjustable refractive index material is disposed within the gap.

An active optical filter adapted for a spectacle lens, the active optical filter configured to filter light radiations over at least one predetermined range of wavelengths, wherein the full width at half maximum of the filtering function of the optical filter is smaller than or equal to 100 nm.

Optical elements with anisotropic, patterned surface relief microstructures in which information is encoded in the distribution of the orientation of different zones. From the analysis of the distribution of the light scattered from the element, the orientation distribution in the element and therefore the encoded information can be evaluated. The elements are particularly useful for securing documents and articles against counterfeiting and falsification.