A novel broadband and wide-angle 2-bit coding metasurface for radar cross section (RCS) reduction is proposed and characterized at terahertz (THz) frequencies. The ultrathin metasurface is composed of four digital elements based on a metallic double cross line structure. The reflection phase difference of neighboring elements is approximately 90° over a broadband THz frequency. The mechanism of...

Terahertz (THz) time-domain spectroscopy probes the optical properties of naturally occurring solid aggregates of minerals, or stones, in the THz frequency range. Refractive index and extinction coefficient measurement reveals that most natural stones, including mudstone, sandstone, granite, tuff, gneiss, diorite, slate, marble, and dolomite, are fairly transparent for THz frequency waves. Dolo...

Communication ‘blackout’ is a big challenge for modern space engineering. In the recent decade, the terahertz (THz) technology is believed to be an effective solution for the ‘blackout’ problem. Many research works about the transmission of THz waves in plasma slabs have been carried out. According to those works, the radio attenuation of THz waves in plasma slabs strongly depends on thickness ...

Coherent tunable terahertz (THz) waves were successfully generated using an injection-seeded THz-wave parametric generator (TPG) based on laser light scattering from the A1-symmetry polariton mode of MgO:LiNbO3 crystals. THz-wave spectrum narrowing to the Fourier transform limit was achieved by injection seeding the idler wave (near-infrared Stokes). This resulted in a THz-wave output approxima...

Terahertz (THz) metasurfaces have been explored recently due to their properties such as low material loss and ease of fabrication compared to three-dimensional (3D) metamaterials. Although the dispersion properties of the reflection/transmission-type THz metasurface were observed in some published literature, the method to control them at will has been scarcely reported to the best of our know...

Terahertz technology [1], at present a dynamically developing field, was enabled by advances in ultra-short pulse lasers and semiconductor coherent sources in the frequency range of 1–50 THz. The extensive activities are focused on THz optics, spectrally bright sources, and detectors. The terahertz time-domain spectroscopy and terahertz imaging are main fields, where terahertz technology finds ...

We demonstrate a new waveguiding structure for terahertz (THz) radiation in which broadband THz pulses are confined and guided along a bare metal wire. The propagation of THz pulses on such a waveguide is characterized with a fiber-coupled terahertz time-domain spectroscopy system. Free-space THz radiation is coupled onto the waveguide at different positions along the wire, and spatially resolv...

The resolution of conventional terahertz (THz) imaging techniques is limited to about half wavelength, which is not fine enough for applications of biomedical sensing and nondestructive testing. To improve the resolution, a new superlens, constructed by a monolayer graphene sheet combining with a grating voltage gate, are proposed in this paper to achieve deep super-resolution imaging in the TH...

We report on the emission patterns from THz plasmons propagating towards the end of cylindrical metal waveguides. Such waveguides exhibit low loss and dispersion, but little is known about the dynamics of the terahertz radiation at the end of the waveguide, specifically in the near- and intermediate-field. Our experimental results and numerical simulations show that the near- and intermediate-f...

The recent growing interest in terahertz (THz) and sub-THz science and technology is due to its many important applications in physics, astronomy, chemistry, biology and medicine, including THz imaging, spectroscopy, tomography, medical diagnosis, health monitoring, environmental control, as well as chemical and biological identification. We review the problem of linear and nonlinear THz and su...