Skirting terahertz waves in a photo-excited nanoslit structure

Abstract

Terahertz fields can be dramatically enhanced as they propagate through nanometer-sized slits. The enhancement is mediated by a significant accumulation of the induced surface charges on the surrounding metal. This enhancement is shown here to be dynamically modulated while the nanoslits are gradually shunted using a copropagating optical beam. The terahertz fields are found to skirt the nanoscale photo-excited region underneath the slits, scattering to the far field and rigorously mapping the near field.

Terahertz-Driven Luminescence and Colossal Stark Effect in CdSe–CdS Colloidal Quantum Dots

“…To concentrate the incident THz radiation we use a simple field enhancement structure (FES) design, a metal microslit array on a SiO2 substrate, which consists of parallel gold lines with 98 µm widths, separated by 2 µm capacitive gaps. Such an FES offers a route to field enhancement factors intermediate between dipole antennas and nanoslit arrays (16,17). A THz field polarized perpendicular to the gold lines ( Fig.…”

Enhancement of terahertz photoconductive antenna operation by optical nanoantennas

“…Another type of perspective THz detectors involves the use of plasmonic structures with resonances in THz frequencies , this technique can also be used for gaining THz spectrometers sensitivity through local field enhancement, however such devices won't fall within the scope of this Review.…”

Air nonlinear dynamics initiated by ultra-intense lambda-cubic terahertz pulses

“…Up to present, the minuscule nonlinear response of air has limited the exploration of its nonlinear properties to the optical frequency regime owing to the availability of intense near-infrared (nIR) lasers (e.g Ti:sapphire with a carrier frequency 380 THz). From a fundamental science point of view nonlinear excitation of air (and other gases) by pulses with a lower carrier frequency, in the so-called terahertz gap Up to now both the observation of Kerr nonlinearities and molecular alignment in air at THz frequencies was hampered by the technological void of intense sources [3][4][5][6][7][8][9]. Field-free alignment/orientation of molecules is conventionally done by nIR laser technology which allows for preparing the molecules in a…”

“…Up to present, the minuscule nonlinear response of air has limited the exploration of its nonlinear properties to the optical frequency regime owing to the availability of intense near-infrared (nIR) lasers (e.g Ti:sapphire with a carrier frequency 380 THz). From a fundamental science point of view nonlinear excitation of air (and other gases) by pulses with a lower carrier frequency, in the so-called terahertz gap (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), is of large interest as the dominating quantities, like the Kerr nonlinear coefficient ( 2 ) are yet unknown. The determination of the air Kerr nonlinear coefficient is essential for prediction and understanding novel nonlinear phenomena [2] such as terahertz (THz) self-guiding (filamentation) and THz self-phase modulation.…”

“…Up to now both the observation of Kerr nonlinearities and molecular alignment in air at THz frequencies was hampered by the technological void of intense sources [3][4][5][6][7][8][9]. Field-free alignment/orientation of molecules is conventionally done by nIR laser technology which allows for preparing the molecules in a 2 preferred angular distribution prior to their interrogation [10,11 and references therein].…”