Saturday, August 30, 2014
Friday, August 29, 2014
R A Lewis
University of Warwick, Department of Physics, Gibbet Hill Road, Coventry, CV4 7AL, UK
Terahertz time-domain spectroscopy permits the coherent motion of charges to be examined in a diverse range of two-dimensional semiconductor heterostructures. Studies of the THz conductivity and magnetoconductivity of two-dimensional quantum systems are reviewed, including cyclotron resonance spectroscopy and the transverse conductivity in the Hall and quantum Hall regimes. Experiments are described that demonstrate quantum phenomena at THz frequencies, principally coherent control and enhanced light–matter coupling in electromagnetic cavities.
Abstract-Rapid scanning terahertz time-domain magnetospectroscopy with a table-top repetitive pulsed magnet
G. Timothy Noe, II, Qi Zhang, Joseph Lee, Eiji Kato, Gary L. Woods, Hiroyuki Nojiri, and Junichiro Kono »View Author Affiliations
Applied Optics, Vol. 53, Issue 26, pp. 5850-5855 (2014)
We have performed terahertz time-domain magnetospectroscopy by combining a rapid scanning terahertz time-domain spectrometer based on the electronically controlled optical sampling method with a table-top minicoil pulsed magnet capable of producing magnetic fields up to 30 T. We demonstrate the capability of this system by measuring coherent cyclotron resonance oscillations in a high-mobility two-dimensional electron gas in GaAs and interference-induced terahertz transmittance modifications in a magnetoplasma in lightly doped
© 2014 Optical Society of America
Abstract-Structural control of metamaterial oscillator strength and electric field enhancement at terahertz frequencies
The design of artificial nonlinear materials requires control over internal resonant charge densities and local distributions. We present a MM design with a structurally controllable strength and local enhancement at terahertz frequencies. The MM consists of a split ring resonator (SRR) array stacked above an array of closed conducting rings. An in-plane, lateral shift of a half unit cell between the SRR and closed ring arrays results in an increase of the MM strength by a factor of 4 and a 40% change in the amplitude of the resonant enhancement in the SRR capacitive gap. We use and numerical simulations to confirm our results. We show that the observed response in this MM is the result of image and currents induced in the closed rings by the SRR.