We report the study of optically induced terahertz (THz) electromagnetic radiation from 〈110〉 oriented zinc-blende crystals. This work extends our previous studies 〈100〉 and 〈111〉 GaAs. Excellent agreement between calculated results experimental data indicates that, under conditions moderate optical fluence normal incidence on unbiased sample, second-order rectification is major nonlinear process that generates THz radiation.

We report optical rectification and subsequent generation of subpicosecond submillimeter-wave radiation from a nonlinear organic crystalline salt. With excitation at wavelength 820 nm 150 fs pulse duration, the magnitude rectified field salt dimethyl amino 4-N-methylstilbazolium tosylate is one two orders larger than that GaAs LiTaO3 crystals, respectively. This crystal presently provides most intense terahertz radiated among all natural nonexternally biased materials we know.

We report the results of coherent measurement (phase and amplitude) optical rectification from a variety electro-optic crystals. also present comparison experimental data with theoretical calculation.

The novel structure exhibits high-efficiency PEC water splitting performance as a result of enhanced light harvesting, accelerated carrier transportation and effective separation.

We report new results on subpicosecond optical rectification near the semiconductor GaAs band gap at room temperature. discriminate between radiation produced by real carriers and that using normal off-normal incident illumination. Under optial illumination of 〈111〉 surface, amplitude nonlinear susceptibility varies dramatically (2 orders magnitude) sign reverses when photon energy is tuned above gap. This resonance enhancement reversal are explained dispersion second-order

We demonstrate the use of a magnetic field to switch and control direction polarization THz beam radiated from semiconductor emitter.

We investigated the terahertz (THz) radiation mechanism of layered tin sulfide (SnS2) crystal via THz emission spectroscopy. Under non-resonant excitation, generation from SnS2 is mainly due to optical rectification effect, which verified by azimuthal angle, polarization and pump fluence dependence signals. Further incident angle dependent signals suggest that progress happened at surface with both in-plane out-of-plane photon-induced dipoles. This work puts forward spectroscopy as a...

Abstract Inspired by the chiral structure from mode interaction, a terahertz metamaterial and its complementary with coexistence of asymmetric transmission circular dichroism response are designed. The happens in presence electric magnetic modes perpendicular to each other, resulting intrinsic chirality under normal incidence. Circular exists parallel other oblique incidence because extrinsic chirality. Both enhanced structures, benefitting coupling between adjacent units. maximum parameter...

The necessity for anti-heat stress workwear to ensure the safety and performance of outdoor workers in hot, humid environments is clear. Yet, there a gap fabric selection techniques that consider multi-criteria decisions account varying functional needs across different body regions. Here, we proposed hybrid decision-making approach, merging efficacy coefficient method, analytic hierarchy process, entropy weight, technique order preference by similarity ideal solution developing ergonomic...

We report the measurement of optically generated THz radiation from over ten different metal/GaAs interfaces. observe an anomalous behavior in beams emitted these In contrast to at normal incidence where amplitude signal decreases with increasing metal film thickness, oblique we increased emission thickness until reaching a maximum near 80 Å.

Surface nonlinear optical response of layered tin disulfide (SnS2) is investigated by terahertz (THz) emission spectroscopy using a femtosecond photoexcitation at 400 nm. Under above-bandgap excitation, we distinguish the surface rectification, electric field (SEF)-induced and SEF-induced drift photocurrent. The pump fluence dependence THz demonstrates saturation effect due to electrostatic screening high photocarrier density on surface. Theoretical calculations suggest that rectification...

We present recent experimental results of difference-frequency generation (DFG) and sum-frequency (SFG) from zincblende materials. measure the radiation field intensity versus crystallographic orientation fundamental photon energy. The simultaneous measurement angular dependence polarized DFG SFG is well characterized by bulk second-order nonlinearity calculation. Pronounced resonant behaviors near GaAs band gap for both radiations (DFG SFG) are compared.

We report measurement of the influence electric and magnetic fields on optically induced THz electromagnetic radiation from semiconductors at normal incidence. The measurements show that strongly amplitude phase transient carrier-generated radiation, but do not affect optical rectification generated by bulk second order nonlinear susceptibility, for static up to 104 V/cm.

We present experimental measurements of Terahertz optical rectification in electro-optic crystals. The measured data was compared with a simple theoretical analysis (anharmonic oscillator model). also Terahertz-bandwidth subpicosecond electromagnetic radiation via nearly-degenerate difference-frequency generation electrooptic materials. variation emission crystal orientation demonstrated that the involves bulk second-order nonlinear process. studied from zincblende crystals as incident...

The spontaneous emission rate of an atom in dielectric slabs is shown to exhibit multiperiodic oscillations when the system scale varied. These are calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. extracted frequencies rates by Fourier transform agree well with actions short photon closed orbits. interpreted as interferences emitted propagating on orbits leaving returning emitting atom. This study provides a new understanding process for atoms presence...

The giant electromagnetic induced transparency (EIT) phenomenon is observed in symmetrical metamaterials with angular dependence the THz region. This due to asymmetrical field distribution on surface of metamaterials, which induces asymmetric current distribution. Blueshift increase unit cell period has been observed, unusual interaction between units at oblique incidence. EIT demonstrates an dependent high Q-factor, sensitive dielectric environment. angle-induced effect could pave way for...

Photodoping as a nonvolatile and reversible method can be used to modify the carrier distribution at heterojunction interface. Herein, we explore 2D/3D van der Waals (vdW) graphene/silicon (G/Si) heterostructure in real time by terahertz (THz) emission spectroscopy. Photoinduced doping is introduced continuous wave laser, which leads screening effect built-in electric field The resulting decrease transient photocurrent reduces THz amplitude from G/Si heterostructure. photoinduced suggests...

The spontaneous emission rate of an atom in a dielectric system with single interface is calculated using quantum electrodynamics and analyzed ideas from closed-orbit theory. shown to exhibit damping oscillation as the atomic distance varied. frequency matches very well prediction This study provides different perspective on atoms presence environments.

Chirality has received wide attention due to its promising applications in biopharmaceuticals, chemical detection, and polarized optoelectronic devices. Herein, metamaterials with layered Tai Chi patterns are proposed get strong tunable chirality. Based on the surface current distribution analysis, a coupling model considering both magnetic electric dipoles upper bottom metallic structures is understand circular dichroism. Accordingly, an external chiral modulation by changing incident angle...