A method of generating THz radiation includes the steps of generating optical input radiation with an input radiation source device (10), irradiating a first conversion crystal device (30) with the optical input radiation, wherein the first conversion crystal device (30) is arranged in a single pass configuration, and generating the THz radiation having a THz frequency in the first conversion crystal device (30) in response to the optical input radiation by an optical-to-THz-conversion process, wherein a multi-line frequency spectrum is provided by the optical input radiation in the first conversion crystal device (30), and the optical-to-THz-conversion process includes cascaded difference frequency generation using the multi-line frequency spectrum. Furthermore, a THz source apparatus being configured for generating THz radiation and applications thereof are described.

THz device includes: a semiconductor substrate; a first semiconductor layer disposed on the semiconductor substrate; an active element formed by being laminated on the first semiconductor layer; a second electrode connected to the first semiconductor layer to be connected to a cathode K of the active element, the second electrode disposed on the semiconductor substrate; a first electrode connected to an anode A of the active element, the first electrode disposed on the semiconductor substrate to be opposite to the second electrode; a rear reflector metal layer disposed on a back side surface of the semiconductor substrate opposite to the first semiconductor layer, wherein the active element forms a resonator between the second and first electrodes, wherein electromagnetic waves are reflected on the rear reflector metal layer, and electromagnetic waves have a surface light-emission radiating pattern or surface light-receiving pattern in a vertical direction to the semiconductor substrate.

The present invention discloses a light-operated adjustable terahertz wave attenuator. The attenuator includes a silicon base-silicon base-vanadium oxide thin film, a laser emitter and a spherical collimating lens, wherein the silicon based-vanadium dioxide thin film is vertical to a terahertz beam direction, the laser emitter is arranged on one side of the silicon based-vanadium dioxide thin film, the laser emitter is connected with the collimator, the laser emitted from the laser emitter is emitted from the collimator and irradiates on a film surface of the silicon based-vanadium oxide thin film, and the spots of the laser irradiating on the film surface of the silicon based-vanadium oxide thin film completely cover the transmitted terahertz wave spots. The present invention further discloses a use method of the light-operated adjustable terahertz wave attenuator.

Provided herein is a large caliber terahertz wave generating device having a photonic crystal structure. The device includes a first electrode and a second electrode. The first electrode includes a first line pattern extending in a first direction, second line patterns coupled to the first line pattern and extending in a second direction, and third line patterns which are coupled to the first line pattern, extend in the second direction, are disposed between the second line patterns, and are longer than the second line patterns. The second electrode includes a fourth line pattern which extends in the first direction, fifth line patterns coupled to the fourth line pattern and extending in the second direction, and sixth line patterns which are coupled to the fourth line pattern, extend in the second direction, are disposed between the fifth line patterns, and are longer than the fifth line patterns.

Acoustically mediated spintronic THz emitters based on a stacked, multilayered heterostructure that includes a light-to-acoustic transducer layer, a thermal insulation layer, and a magnetic layer are provided. In the emitters, fast acoustic pulses give rise to long-distance propagation of THz exchange spin waves in a magnetic film. Also provided are THz time-domain spectrometers (THz-TDSs) that incorporate the THz emitters.

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).

Provided is an optical element including: a main body which is formed of a medium capable of transmitting first light and second light having a wavelength longer than that of the first light, in which the main body includes an incident region into which the first light and the second light are incident, in which a gap which is inclined with respect to the incident region and in which a medium having a refractive index with respect to the first light and the second light lower than that of the main body is disposed is provided inside the main body, and in which a gap width from an interface bordering the main body and the gap is larger than a penetration length of an evanescent wave of the first light at the interface and is smaller than a penetration length of an evanescent wave of the second light at the interface.

An optical waveguide apparatus including a first dispersion unit and a separation unit. The first dispersion unit is connected to the separation unit, the first dispersion unit is configured to disperse a frequency component of at least one first optical signal, and the separation unit is configured to separate, into at least one second optical signal based on configuration information, the frequency component that is of the at least one first optical signal and that is dispersed by the first dispersion unit. The separation unit is implemented by a variable optical waveguide, and the variable optical waveguide is an optical waveguide that implements at least one of the following functions based on the configuration information: forming an optical waveguide, eliminating an optical waveguide, and changing a shape of an optical waveguide.

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.

Provided is a terahertz light source device including an antenna, a plurality of wire electrodes configured to connect the antenna to a power source, a capacitor connected to the wire electrodes between the antenna and the power source, and a plurality of resonance tunneling diodes connected to the wire electrodes between the capacitor and the antenna, and configured to generate a terahertz wave by coupling with the capacitor as a parallel resonance circuit with respect to the power source.