Resonant tunneling diode (RTD) technology is emerging as one of the promising semiconductor-based solid-state technologies for terahertz (THz) wireless communications. This article provides a review state art, with focus on THz RTD oscillator, which key component RTD-based transmitters and coherent receivers. A brief summary device principle operation, technology, modeling, well an overview osc...

introduction: water scarcity is one of the major problems for crop production. using drip irrigation as an effective method in the efficient use of water is expanding in arid and semi-arid regions. one of the problems in under pressure irrigation during use of saline, unconventional and waste is emitters clogging. there are several ways to prevent particle deposits in pipes and clogging of emit...

A single-shot terahertz time-domain spectroscopy method is developed using an echelon-pair. Terahertz waveform is encoded to a beamlets array by electro-optic effect, with a total time window of 37.7 ps and a time step of 94.3 fs. Comparing with spectral encoding methods, this technique directly encodes terahertz waveform to spatial resolution, which is more suited as a terahertz diagnosis for ...

We report the emission of strong coherent broadband terahertz radiation from 6H-silicon-carbide SiC excited with optical pulses. The measured terahertz spectral signal-to-noise ratio is better than one thousand. We determine that the terahertz radiation is generated via second order optical nonlinearity optical rectification . We present a measurement of the ratio of nonlinear susceptibility te...

Phase retarders usually present a strong frequency dependence. We discuss the design and characterization of a terahertz achromatic quarter-wave plate. This wave plate is made from six birefringent quartz plates precisely designed and stacked together. Phase retardation has been measured over the whole terahertz range by terahertz polarimetry. This achromatic wave plate demonstrates a huge freq...

We have measured the terahertz response of oriented Germanium nanowires using ultrafast optical-pump terahertz-probe spectroscopy. We present results on the time, frequency, and polarization dependence of the terahertz response. Our results indicate intraband energy relaxation times of photoexcited carriers in the 1.5-2.0 ps range, carrier density dependent interband electron-hole recombination...

Plasmonic photoconductive antennas have great promise for increasing responsivity and detection sensitivity of conventional photoconductive detectors in time-domain terahertz imaging and spectroscopy systems. However, operation bandwidth of previously demonstrated plasmonic photoconductive antennas has been limited by bandwidth constraints of their antennas and photoconductor parasitics. Here, ...

The development of effective techniques for guiding pulsed terahertz radiation is essential for the continued development of terahertz spectroscopy and imaging applications based on the technique of time-domain spectroscopy. Terahertz surface plasmon polaritons (SPPs) can be excited and guided on cylindrical metal wires with low loss and dispersion. This propagating surface wave, known as a Som...

The distinctive ability of nanometallic structures to manipulate light at the nanoscale has recently promoted their use for a spectacular set of applications in a wide range of areas of research including artificial optical materials, nano-imaging, biosensing, and nonlinear optics. Here we transfer this concept to the terahertz spectral region, demonstrating a metal nanostructure in shape of a ...

One key factor that limits resolution of single-molecule superresolution microscopy relates to the localization accuracy of the activated emitters, which is usually deteriorated by two factors. One originates from the background noise due to out-of-focus signals, sample auto-fluorescence, and camera acquisition noise; and the other is due to the low photon count of emitters at a single frame. W...