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We present experimental und numerical investigations on the excitation, optimization and propagation of terahertz surface waves on silicon substrates. A single metamaterial layer is used to enhance the spatial confinement of the surface wave at the interface between air and silicon. The electric terahertz field of the surface wave is measured by a 2D near field scan.
We propose a novel way to actively control the propagation of THz Surface Plasmon Polariton (SPPs) in plasmonic waveguides structured on semiconductors. The SPP characteristics (field confinement and mode propagation length) can be precisely tuned by optically pumping charge carriers to the conduction band of the semiconductor. This approach can be used to generate active and integrated THz components...
Here, we demonstrate the possibility of employing a novel low-loss dielectric material as substrate for free-space THz devices through the design, fabrication and characterization of broadband high-transparency high-pass mesh filters. Time-domain spectroscopy measurements show that a transmittance higher than 75% is achieved over a bandwidth of 1 THz.
Propagation of terahertz surface plasmon polaritons along plane metal-dielectric interfaces and their jumps across air gaps have been studied using monochromatic radiation of Novosibirsk free electron laser.
This paper presents the use of Terahertz (THz) SPR near-field sensor based on array of sub-wavelength metallic holes and Bull's eye structure to characterize materials such as PMMA and those used in organic light emitting diode (OLED). The measurement results confirmed the theoretical SPR frequencies for metal-silicon mode and demonstrate a shift to 0.9211 THz from 0.9375 THz due to 2 µm of PMMA layer...
We report on the observation of terahertz (THz) radiation emitted from monoclinic bismuth vanadate (BiVO4) and gold (Au) thin film interfaces, irradiated with femtosecond laser pulses. The emitted terahertz pulses show a second-order dependence on the pump power. THz radiation was measured for different thicknesses of BiVO4 and the possible reasons for this thickness dependence are also discussed.
Pulsed broadband terahertz emission can be observed from lateral diffusion currents near the surface of a partially metallic masked semiconductor after ultrafast photoexcitation. We present a theoretical mechanism for the emission based on diffusion and dipole suppression under the metal mask with supporting experimental and theoretical evidence.
We demonstrate scanning near-field optical microscopy with a spatial resolution below 100 nm by using broadband synchrotron radiation in the infrared range provided by the Metrology Light Source. This approach opens up the possibility to perform Fourier transform infrared spectroscopy on a nanoscale.
Upon femtosecond laser pumping of a topological insulator Bi2Se3, we observed efficient THz generation from the surface electrons. By performing polarization-resolved studies on the emitted THz spectrum, two emission mechanisms are identified. THz emission spectroscopy provides a valuable spectroscopic tool for studies of the dynamics of the surface electrons in centrosymmetric topological insulators.
THz emission from thin film Schottky junctions is enhanced using plasmonic nano-gratings. Enhancement factors of up to 5.6 are observed in the emitted electric field, corresponding to a power enhancement factor of ∼34.
THz pulse emission from GaAs and GaAs-MnAs nanowire (NW) samples illuminated by femtosecond laser pulses has been studied. The amplitude of THz pulses emitted by nanowire samples was more than twice larger than that radiated from GaAs substrate. It was found that terahertz emissivity of NW samples rapidly decreases with increasing laser photon energy - behavior that could be explained by localized...
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