The invention provides flash imaging devices that include an optical change component that undergoes a change in response to an applied stimulus, a substrate and a stimulus element. Also provided are articles that include the subject devices, as well as methods of making and using the same.

A high-electron mobility transistor (HEMT) array terahertz wave modulator loaded in a waveguide is provided, which belongs to the technical field of electromagnetic functional devices and focuses on fast dynamic functional devices in the terahertz band. The device comprises a waveguide cavity and a modulation chip. The modulation chip comprises a semiconductor material substrate, a heterostructure material epitaxial layer, an artificial microstructure, and a socket circuit. The applied voltage controls the distribution change of the two-dimensional electron gas in the HEMT, which in turn controls the resonance mode conversion in the artificial microstructure, thereby control the transmission of electromagnetic waves in the waveguide. The modulator has a modulation depth of up to 96% and a modulation rate above 2 GHz. The invention can be realized by using micro-processing technology, and the preparation process is mature and reliable.

A reconfigurable polar molecule includes a symmetric nonpolar molecule portion having an elongated shape defined by a longitudinal axis and lateral axis, the longitudinal axis being longer than the lateral axis; a positive ionically charged group at a first end and a negative ionically charged group at a second end of the longitudinal axis, the positive and negative ionically charged groups forming a permanent dipole; a first bridging group and a second bridging group on opposing ends of the lateral axis, the first and second bridging groups being linear nonpolar groups; and a first support portion bonded to the first bridging group, and a second support portion bonded to the second bridging group, the first bridging group and the second bridging group being nonpolar and having structures that enable free rotation of the symmetric nonpolar molecule portion through the first bridging group and the second bridging group.

An electro-optical modulator using a graphene-based plasmonic slot is disclosed. The electro-optical modulator is comprised of a substrate layer, a dielectric spacer, a graphene layer, a first metal layer, and a second metal layer. The metal layers create a plasmonic slot that modulates between a light absorptive and light transparent state depending on the application of voltage across the modulator. Two or four graphene layers may be used to reduce power consumption and the size of the modulator.

A method for designing a metasurface is provided. The method may include selecting a first metamaterial structure of a plurality of metamaterial structures of the metasurface; generating a forward light propagation model for the first metamaterial structure; generating a reciprocal light propagation model for the first metamaterial structure using a light manipulation function for the metasurface; determining a first electromagnetic response difference between the forward light propagation model and the reciprocal light propagation model; and determining a first property range of the first metamaterial structure such that the first electromagnetic response difference is optimized.

A spaser device comprises a graphene resonator and a carbon nanotube (CNT) gain element coupled via exciton-plasmon interaction. The graphene resonator may be a rectangular or square graphene nanoflake (GNF), and the CNT gain element may be characterized by chirality vector (n,m) selected such that the CNT has semiconducting properties. The CNT gain element may be illuminated using a light source having a photon energy corresponding with a first exciton energy (E.sub.22) of the CNT, whereby excitons having a second exciton energy (E.sub.11) less than the first exciton energy are generated in the CNT, and coupled to a surface plasmon (SP) mode of the graphene resonator. When the rate of generation of excitons having the second exciton energy exceeds a gain threshold, continuous spasing is established within the spaser device.

In one embodiment, a chromatic device includes an active layer and an electrolyte layer in contact with the active layer, the electrolyte comprising an oxidant and a salt, wherein the active layer has a color that blocks light when metal is not in electrical contact with the active layer but changes to a translucent color that transmits light when metal is placed in electrical contact with the active layer, wherein the active layer changes color without applying electrical energy to the active layer.

An optical device includes a nanostructured transparent dielectric film, which is a Huygens metasurface. The Huygens metasurface imparts a phase change to light propagating through or reflecting from the surface. The phase change can be achieved by means of a resonant interaction between light and the Huygens resonators, resulting in a controllable phase change of 0 to 2 with approximately 100% light transmission characterized by a below 0.1 dielectric loss tangent of delta and with the height of the resonators less than the wavelength of light. In one embodiment, the metasurface includes titanium dioxide, but many materials or stacks of different materials may be used. The optical device is functional throughout the visible spectrum between 380 and 700 nm. The nanostructured transparent dielectric film includes a plurality of Huygens resonators. The phase and the amplitude of the nanostructured transparent dielectric film are modulated by arranging the plurality of Huygens resonators such that certain properties, including the radius and height of each Huygens resonator, as well as the gap between two adjacent Huygens resonators, are controlled to optimize the performance of the optical device within the visible spectrum.

The invention provides flash imaging devices that include an optical change component that undergoes a change in response to an applied stimulus, a substrate and a stimulus element. Also provided are articles that include the subject devices, as well as methods of making and using the same.

An optical device includes a nanostructured transparent dielectric film, which is a Huygens metasurface. The Huygens metasurface imparts a phase change to light propagating through or reflecting from the surface. The phase change can be achieved by means of a resonant interaction between light and the Huygens resonators, resulting in a controllable phase change of 0 to 2 with approximately 100% light transmission characterized by a below 0.1 dielectric loss tangent of delta and with the height of the resonators less than the wavelength of light. In one embodiment, the metasurface includes titanium dioxide, but many materials or stacks of different materials may be used. The optical device is functional throughout the visible spectrum between 380 and 700 nm. The nanostructured transparent dielectric film includes a plurality of Huygens resonators. The phase and the amplitude of the nanostructured transparent dielectric film are modulated by arranging the plurality of Huygens resonators such that certain properties, including the radius and height of each Huygens resonator, as well as the gap between two adjacent Huygens resonators, are controlled to optimize the performance of the optical device within the visible spectrum.