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.

A nanoscale circuit has an optical antenna receiving the radiation from a mode-locked laser and it responds by transmitting selected microwave or terahertz frequencies with a separate orthogonal antenna. Only MIM diodes, low-pass filters, and a load resistor are used to generate, separate, and transmit at the harmonics of the laser pulse-repetition rate.

Provided are an apparatus and method of generating a terahertz (THz) signal using a directly-modulated laser. An apparatus of generating a THz signal includes a first directly-modulated laser configured to output a local oscillator (LO) signal, a second directly-modulated laser configured to receive a baseband signal used as data and optically modulate the baseband signal, a band-pass filter configured to filter a spectral component of the baseband signal optically modulated and outputted through the second directly-modulated laser by using a specific frequency bandwidth, a coupler configured to couple the baseband signal filtered through the band-pass filter and the LO signal to each other, and a uni-travelling-carrier photodiode (UTC-PD) configured to generate a THz signal by beating the baseband signal and the LO signal coupled to each other.

Systems and methods in accordance with embodiments of the invention implement electronic frequency-comb detector systems. One embodiment includes an electronic frequency-comb detector, where the electronic frequency-comb detector includes: a frequency-comb generator configured to generate a frequency comb reference signal, and a heterodyne mixer. In addition, the heterodyne mixer is configured to use the frequency comb reference signal to downconvert received millimeter wave (mm-wave) and terahertz (THZ) frequency tones into an intermediate frequency (IF) signal. In a further embodiment, the electronic frequency-comb detector includes an IF amplifier, where the IF amplifier is configured to feed a spectrum analyzer configured to detect a signature of a material under test (MUT).

Systems and methods in accordance with embodiments of the invention implement electronic frequency-comb detector systems. One embodiment includes an electronic frequency-comb detector, where the electronic frequency-comb detector includes: a frequency-comb generator configured to generate a frequency comb reference signal, and a heterodyne mixer. In addition, the heterodyne mixer is configured to use the frequency comb reference signal to downconvert received millimeter wave (mm-wave) and terahertz (THZ) frequency tones into an intermediate frequency (IF) signal. In a further embodiment, the electronic frequency-comb detector includes an IF amplifier, where the IF amplifier is configured to feed a spectrum analyzer configured to detect a signature of a material under test (MUT).

Disclosed are a terahertz signal generation apparatus and a terahertz signal generation method using the same. The terahertz signal generation apparatus includes first and second resonators configured to respectively output an optical signal of a first resonant frequency and an optical signal of a second resonant frequency from an optical signal input through a gain medium, an optical modulator configured to optically modulate the output optical signal of the second resonant frequency, an optical combiner configured to combine the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, and a signal generator configured to generate a terahertz signal using heterodyne beating between the CW optical signal of the first resonant frequency and the modulated optical signal of the second resonant frequency, wherein the first resonant frequency and the second resonant frequency are processed to have a predetermined frequency difference.

Devices, systems and methods for biological sensing and communication using optogenetics and electronics are described. One example method includes generating a light beam incident on multiple regions in a device, wherein each region comprises an optogenetic system to generate, upon interacting with the light beam, biosensors, wherein an interaction between the biosensors and stimulus molecules in each region is associated with a threshold for a production of an output molecule or an alteration of an output property of the output molecule, the biosensors, or the stimulus molecules, wherein the production or the alteration is based on a value associated with an information source, detecting an output received from one or more of the multiple regions corresponding to the output molecule or the output property in that region, and generating an electric signal associated therewith, and processing the electrical signal to determine the value associated with the information source.

Described is a method of setting up a plurality of quantum communications links, forming a quantum network providing provably secure communications and internet services over intercontinental distances without requiring direct line of sight communication or the intermediate use of the entanglement resource of satellites. Also described is a quantum communicator device for use in this method. Two or more quantum memory units are disposed at a first location, an entangled link is set up between at least two of the quantum memory units, at least one of the quantum memory units sharing in the entangled link is physically transported to a second location. The quantum communicator device comprises communications nodes, an optical interface to set up entanglement to other devices and storage nodes, each node in the form of a quantum memory unit capable of storing quantum information for a desired length of time, i.e. weeks or longer.

Described is a method of setting up a plurality of quantum communications links, forming a quantum network providing provably secure communications and internet services over intercontinental distances without requiring direct line of sight communication or the intermediate use of the entanglement resource of satellites. Also described is a quantum communicator device for use in this method. Two or more quantum memory units are disposed at a first location, an entangled link is set up between at least two of the quantum memory units, at least one of the quantum memory units sharing in the entangled link is physically transported to a second location. The quantum communicator device comprises communications nodes, an optical interface to set up entanglement to other devices and storage nodes, each node in the form of a quantum memory unit capable of storing quantum information for a desired length of time, i.e. weeks or longer.

A wireless communication system comprises a base station and one or more relay docks and transmits directional wave signals between components using high frequency waves, such as millimeter waves. A beam forming decision engine utilizes position information collected from one or more position or motion sensors of a user device to determine a direction in which to form a directional wave signal being transmitted between components of the wireless communication system.