Apparatus for generating THz (teraftertz) radiation, the apparatus comprising: a substrate; a planar array of subwave-length antennas formed on the substrate having rotational symmetry, Cn, of order “n” greater than or equal to 3 and rotational symmetry cycle 2π/η, which are excitable by near infrared (NIR)_pump radiation to radiate THz radiation having wavelengths that are substantially larger than characteristic dimensions of the subwavelength antenna; wherein the array comprises a plurality of sections each comprising plurality of subwavelength antennas exhibiting a spatial pattern different from that of an adjacent section of the plurality of sections.

A silicon based terahertz full wave liquid crystal phase shifter is provided. The liquid crystal phase shifter has a first silicon conductive substrate, a second silicon conductive substrate, a plurality of pads, and a liquid crystal. The first and second silicon conductive substrates, instead of the quartz glass and transparent electrode, such as ITO, are used as substrates and to provide electrodes of the liquid crystal phase shifter. Thus, the effect of the liquid crystal phase modulation of the liquid crystal phase shifter in the THz range can be improved.

An embodiment of the present invention provides a continuous-wave terahertz generation and detection device using a photomixing technique, the device including: first and second light source units configured to output continuous-wave laser light sources, which have single wavelength and different frequencies, to generate optical signals; a first electro-optic phase modulator configured to shift a frequency of the optical signal generated by the first light source unit, and a second electro-optic phase modulator configured to shift a frequency of the optical signal generated by the second light source unit; a first optical amplifier configured to receive and amplify the optical signal whose frequency is shifted by the first electro-optic phase modulator and the optical signal generated by the second light source unit, and a second optical amplifier configured to receive and amplify the optical signal whose frequency is shifted by the second electro-optic phase modulator and the optical signal generated by the first light source unit; an opto-electronic converter configured to convert the optical signal amplified by the first optical amplifier into a terahertz wave; a photomixer configured to mix the optical signal amplified by the second optical amplifier and the terahertz wave generated by the opto-electronic converter and convert the mixed signal into an electrical signal; a photodetector configured to combine the optical signals transferred from the first and second optical amplifiers and convert the combined optical signal into an electrical signal; and a filter unit configured to filter the electrical signal passing through the photodetector, wherein the electrical signal obtained through the photodetector is compared with the electrical signal obtained by the photomixer, and phase noise having the same frequency is removed.

A system and method for separating signal quadratures includes obtaining, by a parametric amplifier, an input signal, amplifying, by the parametric amplifier, the input signal to create an amplified signal and generating an idler. The idler is a conjugate image of the input signal. The system and method also include obtaining, by a frequency converter, the amplified signal and the conjugate image and converting the amplified signal and the conjugate image into a first output and a second output, where the first output includes a first signal quadrature and the second output includes a second output quadrature.

Terahertz spectrometer having a wider range of terahertz radiation source, high temporal resolution of scanning (<0.0.099 μm or ˜0.3 pico second) over a wider range of scanning (up to ˜100 pico seconds). Also disclosed are exemplary applications of the spectrometer in biomedical, biological, pharmaceutical, and security areas.

Disclosed are a modulated terahertz (THz) signal deflector and a preparation method thereof. The modulated THz signal deflector includes: a first transparent substrate and a second transparent substrate that are oppositely disposed, a liquid crystal layer, a transparent electrode layer, and a photo-alignment layer, wherein the photo-alignment layer has a control graph in which a molecule director is periodically and gradiently distributed along a specific direction, and the control graph is configured to control a liquid crystal molecule director in the liquid crystal layer to be periodically and gradiently distributed along a specific direction to form a blazed-grating phase distribution based on a geometric phase, and deflect an incident circularly polarized THz signal to a specific angle. The deflector provided in the present disclosure can deflect a THz signal to a specific angle, and can switch signal deflection and non-deflection functions by powering up a transparent electrode.

A coherent frequency modulated receiver for receiving and detecting arriving optical signals which comprises an electrically controllable optical beam scanner receiving optical input beams arriving at different angles in a field of view of the electrically controllable optical beam scanner, the electrically controllable optical beam scanner conveying a scanned optical input beam as its output optical beam; a grating coupler responsive to the output or reflected optical beam of the electrically controllable optical beams scanner, the grating coupler having a waveguided output; an optical local oscillator laser having a waveguided output; an FMCW signal generator; an optical modulator responsive to the optical waveguided outputs of the optical local oscillator laser and also to an electrical FMCW signal from the FMCW signal generator; a pair of second order non-linear optical elements for frequency upconverting respective outputs of the optical modulator and the grating coupler; and at least one photodiode optically coupled to an outputs of the pair of second order non-linear optical elements.

Optical devices that include one or more structures fabricated from polar-dielectric materials that exhibit surface phonon polaritons (SPhPs), where the SPhPs alter the optical properties of the structure. The optical properties lent to these structures by the SPhPs are altered by introducing charge carriers directly into the structures. The carriers can be introduced into these structures, and the carrier concentration thereby controlled, through optical pumping or the application of an appropriate electrical bias.

In a terahertz wave generation apparatus including a first non-linear optical crystal 3 on which first laser L1 and second laser L2 from laser generation means 2 are incident to generate terahertz wave TH1, the laser generation means includes a second non-linear optical crystal 7 on which laser having the same wavelength as that of the second laser is incident to generate idler light L1 including a plurality of wavelengths, and makes the idler light L1 generated from the second non-linear optical crystal incident on the first non-linear optical crystal as the first laser L1, to generate terahertz wave including a plurality of wavelengths from the first non-linear optical crystal 3, and wavelength selection means including a transmission section which transmits an idler light having the specific wavelength in the idler light including the plurality of wavelengths can be provided, as needed. Thus, terahertz wave having a high output power and including a plurality of wavelengths can be obtained, and the wavelength selection means easily obtains a required terahertz wave having the specific wavelength.

A signal transfer link includes a first plasmonic coupler, and a second plasmonic coupler spaced apart from the first plasmonic coupler to form a gap. A plasmonic conductive layer is formed over the gap to excite plasmons to provide signal transmission between the first and second plasmonic couplers.