G. L. Woods | Searcharxiv

arXiv2014

Rapid Scanning Terahertz Time-Domain Magnetospectroscopy with a Table-Top Repetitive Pulsed Magnet

We have performed terahertz time-domain magnetospectroscopy by combining a rapid scanning terahertz time-domain spectrometer based on the electronically coupled optical sampling method with a table-top mini-coil 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 n-InSb.

cond-mat.mtrl-sci↗

arXiv2013

Midinfrared Third Harmonic Generation from Macroscopically Aligned Ultralong Single-Wall Carbon Nanotubes

We report the observation of strong third harmonic generation from a macroscopic array of aligned ultralong single-wall carbon nanotubes (SWCNTs) with intense midinfrared radiation. Through power-dependent experiments, we determined the absolute value of the third-order nonlinear optical susceptibility, $χ^{(3)}$, of our SWCNT film to be 5.53 $\times$ 10$^{-12}$ esu, three orders of magnitude larger than that of the fused silica reference we used. Taking account of the filling factor of 8.75% for our SWCNT film, we estimate a $χ^{(3)}$ of 6.32 $\times$ 10$^{-11}$ esu for a fully dense film. Furthermore, through polarization-dependent experiments, we extracted all the nonzero elements of the $χ^{(3)}$ tensor, determining the magnitude of the weaker tensor elements to be $\sim$1/6 of that of the dominant $χ^{(3)}_{zzzz}$ component.

cond-mat.mes-hall↗