A liquid crystal device including a single or a plurality of pixel elements is provided. Each pixel element includes: a first substrate, a second substrate parallel to the first substrate, a liquid crystal layer disposed between the first substrate and the second substrate, a first plurality of electrodes formed between the first substrate and the liquid crystal layer, a second plurality of electrodes formed between the second substrate and the liquid crystal layer. The first plurality of electrodes and the second plurality of electrodes are composed to generate electric fields in three orthogonal directions, and the electric fields in two of the three orthogonal directions are in-plane electric fields, while the other electric field of the three orthogonal directions is an out-of-plane electric field.

A fast optical (with or without a photonic crystal) switch is fabricated/constructed, utilizing a phase transition material/Mott insulator, activated by either an electrical pulse (a voltage pulse or a current pulse) and/or a light pulse and/or pulses in terahertz (THz) frequency of a suitable field strength and/or hot electrons. The applications of such a fast optical switch for an on-demand optical add-drop subsystem, integrating with (a) a light slowing/light stopping component (based on metamaterials and/or nanoplasmonic structures) and (b) with or without a wavelength converter are also described.

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.

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.

A nonlinear fiber interferometer is disclosed suitable for fiber sensor and other applications. A first nonlinear fiber section amplifies probe and conjugate sidebands of a pump through four-wave mixing. A second section introduces a phase shift to be measured, for example from a sensor. A third nonlinear fiber section amplifies with phase-sensitive gain to increase signal-to-noise ratio. Based on phase-sensitive output power of probe and/or conjugate components, the phase shift can be measured. Superior performance can be obtained by balancing gain between the (first and third) nonlinear sections. Non-fiber, for example photonic integrated circuit, embodiments are disclosed. Differential sensing, alternative detection schemes, sensing applications, associated methods, and other variations are disclosed.

A terahertz modulator includes a substrate and an organic semiconductor layer. A material of the organic semiconductor layer is graphitic carbon nitride, and the organic semiconductor layer is coated on a surface of the substrate. The terahertz modulator has a high on-off contrast and is able to reach a high modulation speed. A terahertz spatial light modulator includes a terahertz modulator and an automatic pumped light spatial modulator. The automatic pumped light spatial modulator is optically connected with the terahertz modulator. The terahertz spatial light modulator generates a patterned terahertz light, and the terahertz spatial light modulator has a high on-off contrast and is able to reach a high modulation speed.

A photonic device and a continuous-wave THz signal generator using such photonic device. The photonic device includes an input waveguide arranged to receive input waves of at least two input frequencies and to generate photons at an output frequency associated with the at least two input frequencies; an output waveguide coupled to the input waveguide and arranged to collect the generated photons at the output frequency; wherein the output waveguide is further arranged to facilitate an amplification of the generated photons as the generated photons propagates along the output waveguide and arranged to output an amplified signal at the output frequency.

The present disclosure relates to the technical field of terahertz (THz) wave measurement and relates to a photo-thermo-acoustic mechanism-based power measurement apparatus and measurement method for a terahertz wave at room temperature. The apparatus includes a terahertz wave power modulation component, a photo-thermo-acoustic conversion device, and an acoustic wave measurement component. In the present disclosure, the THz absorbing substance having a photo-thermo-acoustic effect is used as the photo-thermo-acoustic conversion device. A power-modulated terahertz wave is converted into an acoustic wave pulse by means of the photo-thermo-acoustic mechanism. The acoustic wave measurement component measures the acoustic wave pulse. A peak-to-peak value of a pulse of the measured acoustic wave is proportional to the power of the terahertz wave, thereby implementing the fast broadband measurement of the terahertz wave power at room temperature.

The present invention provides a far-infrared light source capable of reducing the shift in the location irradiated with far-infrared light even when the frequency of the far-infrared light changes. A far-infrared light source according to the present invention is configured so that the variation in the emission angle of far-infrared light in a nonlinear optical crystal when the frequency of the far-infrared light changes is substantially offset by the variation in the refractive angle of the far-infrared light at the interface between the nonlinear optical crystal and a prism when the frequency of the far-infrared light changes (see FIG. 8).

An optoelectronic component for generating and radiating an electromagnetic signal exhibiting a frequency lying between 30 GHz and 10 THz referred to as a microwave frequency, comprises: a planar guide configured to confine and propagate freely in a plane XY a first and a second optical wave exhibiting an optical frequency difference, referred to as a heterodyne beat, equal to the microwave frequency, a system for injecting the optical waves into the planar guide, a photo-mixer coupled to the planar guide to generate, on the basis of the first optical wave and of the second optical wave, a signal exhibiting the microwave frequency, the photo-mixer having an elongated shape exhibiting along an axis Y a large dimension greater than or equal to half the wavelength of the signal, the injection system configured so that the optical waves overlap in the planar guide and are coupled with the photo-mixer over a length along the axis Y at least equal to half the wavelength of the signal, the photo-mixer thus being able to radiate the signal.