Abstract: Disclosed herein are systems and methods of nano-engineered optical metasurfaces and materials able to generate higher efficiency flat optics and controlled surface emission via photothermally reconfigurable optical metasurfaces based on optical phase change materials (PCMs). Through localized control of the material dispersion, devices can operate at higher amplitudes and phase control for greater efficiency across larger operational bandwidth in the optical and infrared (IR) spectral regions.

Abstract: A method for constructing a multifunctional antenna structure configured to generate a plurality of radiation patterns includes determining a desired source field associated with the plurality of radiation patterns, and receiving feed locations for a waveguide to an antenna aperture surface. The method may further include placing a metasurface resonator at a first resonator location that exhibits a minimum error relative to the desired source field and satisfies a maximum error threshold relative to the desired source field. The metasurface resonator may be determined based on the feed locations and a plurality of degrees of freedom for the first resonator location. The method may also include discarding a second resonator location in response to determining that no metasurface resonator at the second resonator location satisfies the maximum error threshold. The plurality of degrees of freedom may include metasurface resonator geometries that exhibit different polarizabilities defined in a candidate library.

Abstract: A metasurface device in the form of a unit cell may include a first metasurface sub-cell configured to exhibit a first resonant electromagnetic field (EMF) response and a second metasurface sub-cell configured to exhibit a second resonant EMF response. Each the two metasurface sub-cells may include a patterned layer and a variable impedance element operably coupled to the patterned layer. The variable impedance element may be configured to, in response to receipt of a control signal, change an impedance of the respective metasurface sub-cell based on the control signal to change the EMF response of the sub-cell. The first metasurface sub-cell and the second metasurface sub-cell may be disposed in a cascaded configuration such that first EMF response and the second EMF response couple to exhibit an integrated EMF response for the metasurface unit cell.

Abstract: Methods and systems for growing thin films via molecular-beam epitaxy (MBE) on substrates are provided. The methods and systems utilize a thermally conductive backing plate including an infrared-absorbing coating (IAC) formed, for example, on one side of the thermally conductive backing plate to provide an asymmetric emissivity that absorbs infrared radiation (IR) on the side having the IRC and does not on the non-coated side of the thermally conductive backing plate (e.g., refractive metal or alloy). The asymmetric emissivity shields the thin film being deposited on a substrate from the IR during formation.

Abstract: A device for imaging light, or a source of the light, includes a window for receiving incident light from the source, at least one metasurface, and at least one wedge prism. The metasurface and the wedge prism form a Risley pair and are displaced independently of each other. Each of the metasurface and the wedge prism are operative to deflect the incident light at an angle that is different from an angle of light incident upon them. Each metasurface includes a plurality of sub-wavelength structures that are operative to interact with the incident light received from the window. The device also includes a lens system that is operative to transmit the incident light received from the at least one metasurface and the at least one wedge prism and focuses it on a focal plane.

Abstract: A fabrication method includes depositing a semiconductor material onto a substrate, applying hard mask layer and a photoresist layer, and performing lithography to form voids in the photoresist layer that form a pattern. Additionally, the method may include patterning the hard mask layer based on the pattern in the photoresist layer and etching the semiconductor material based on the patterned hard mask layer to form a cavity in the semiconductor material, and performing atomic layer deposition to deposit pillar material into the cavity including the sidewalls of the cavity such that the pillar material accumulates inwardly from the sidewalls until the cavity is filled. The method may also include planarizing to remove the hard mask layer and pillar material disposed above a pillar height from a surface of the substrate, and removing the semiconductor material to release a pillar of the pillar material supported by the substrate.

Abstract: A composite and an adaptive coating are provided. The composite includes a first layer, a second layer disposed on the first layer, and a third layer disposed on the second layer. The third layer constitutes a phase change material characterized by a transition temperature. The phase change material includes a dopant. The adaptive coating includes a visible light filter and the phase change material. When a temperature of the phase change material exceeds a threshold temperature, the adaptive coating is configured to radiate light in the infrared spectrum. When the temperature of the phase change material is less than the threshold temperature, the adaptive coating is configured not to radiate light in the infrared spectrum.

Abstract: A method for constructing a multifunctional antenna structure configured to generate a plurality of radiation patterns includes determining a desired source field associated with the plurality of radiation patterns, and receiving feed locations for a waveguide to an antenna aperture surface. The method may further include placing a metasurface resonator at a first resonator location that exhibits a minimum error relative to the desired source field and satisfies a maximum error threshold relative to the desired source field. The metasurface resonator may be determined based on the feed locations and a plurality of degrees of freedom for the first resonator location. The method may also include discarding a second resonator location in response to determining that no metasurface resonator at the second resonator location satisfies the maximum error threshold. The plurality of degrees of freedom may include metasurface resonator geometries that exhibit different polarizabilities defined in a candidate library.

Abstract: A metasurface unit cell for use in constructing a metasurface array is provided. The unit cell may include a ground plane layer comprising a first conductive material, and a phase change material layer operably coupled to the ground plane layer. The phase change material layer may include a phase change material configured to transition between an amorphous phase and a crystalline phase in response to a stimulus. The unit cell may further include a patterned element disposed adjacent to the phase change material layer and includes a second conductive material. In response to the phase change material transitioning from a first phase to a second phase, the metasurface unit cell may resonate to generate an electromagnetic signal having a defined wavelength. The first phase may be the amorphous phase or the crystalline phase and the second phase may be the other of the amorphous phase or the crystalline phase.

Abstract: An apparatus includes a substrate, a first patterned layer, and a second patterned layer. The first patterned layer may be coupled to the substrate and may have a first metasurface pattern. The second patterned layer disposed separately from the substrate and the first patterned layer, and may have a second metasurface pattern. Movement of the first patterned layer relative to the second patterned layer may be controllable via control circuitry such that a gap distance of a gap between the first patterned layer and the second patterned layer is changed to cause a transmittance for radiant energy of a selected wavelength passing through the apparatus to change from a first transmittance value to a second transmittance value.

Abstract: A reconfigurable reflectarray antenna (RAA) system includes a reconfigurable RAA and a controller. The RAA includes a metasurface having a dynamically tunable electromagnetic characteristic and is configured to receive a signal of opportunity. The signal of opportunity is generated separately and independently from the reconfigurable RAA system. The controller is in signal communication with the reconfigurable RAA and is configured to generate a control signal configured to dynamically tune the electromagnetic characteristic of the metasurface. The electromagnetic characteristic includes a reflection phase, which when varied, dynamically beam steers the signal of opportunity reflected from the metasurface.

Abstract: Methods and systems for growing thin films via molecular-beam epitaxy (MBE) on substrates are provided. The methods and systems utilize a thermally conductive backing plate including an infrared-absorbing coating (IAC) formed, for example, on one side of the thermally conductive backing plate to provide an asymmetric emissivity that absorbs infrared radiation (IR) on the side having the IRC and does not on the non-coated side of the thermally conductive backing plate (e.g., refractive metal or alloy). The asymmetric emissivity shields the thin film being deposited on a substrate from the IR during formation.

Abstract: A reconfigurable reflectarray antenna (RAA) system includes a reconfigurable RAA and a controller. The RAA includes a metasurface having a dynamically tunable electromagnetic characteristic and is configured to receive a signal of opportunity. The signal of opportunity is generated separately and independently from the reconfigurable RAA system. The controller is in signal communication with the reconfigurable RAA and is configured to generate a control signal configured to dynamically tune the electromagnetic characteristic of the metasurface. The electromagnetic characteristic includes a reflection phase, which when varied, dynamically beam steers the signal of opportunity reflected from the metasurface.

Abstract: A metasurface unit cell for use in constructing a metasurface array is provided. The unit cell may include a ground plane layer comprising a first conductive material, and a phase change material layer operably coupled to the ground plane layer. The phase change material layer may include a phase change material configured to transition between an amorphous phase and a crystalline phase in response to a stimulus. The unit cell may further include a patterned element disposed adjacent to the phase change material layer and includes a second conductive material. In response to the phase change material transitioning from a first phase to a second phase, the metasurface unit cell may resonate to generate an electromagnetic signal having a defined wavelength. The first phase may be the amorphous phase or the crystalline phase and the second phase may be the other of the amorphous phase or the crystalline phase.

Abstract: An apparatus includes a substrate, a first patterned layer, and a second patterned layer. The first patterned layer may be coupled to the substrate and may have a first metasurface pattern. The second patterned layer disposed separately from the substrate and the first patterned layer, and may have a second metasurface pattern. Movement of the first patterned layer relative to the second patterned layer may be controllable via control circuitry such that a gap distance of a gap between the first patterned layer and the second patterned layer is changed to cause a transmittance for radiant energy of a selected wavelength passing through the apparatus to change from a first transmittance value to a second transmittance value.

Abstract: An antenna is provided including an electromagnetic metasurface. The electromagnetic characteristics of the antenna are dynamically tunable.

Abstract: An antenna is provided including an electromagnetic metasurface. The electromagnetic characteristics of the antenna are dynamically tunable.