Preparation, alignment, and optical properties of soluble poly(phenylacetylene)-wrapped carbon nanotubes

Carbon nanotube-containing poly(phenylacetylenes) (NT/PPAs) are prepared by in situ polymerizations of phenylacetylene catalyzed by WCl6-Ph4Sn and [Rh(nbd)Cl](2) (nbd = 2,5-norbornadiene) in the presence of the nanotubes. The NT/PPAs are characterized by GPC, NMR, UV, FL, TGA, SEM, TER;I, and XRD, and it is found that the nanotubes in the NT/PPAs are helically wrapped by the PPA chains. The short nanotubes thickly wrapped in the PPA chains are soluble in common organic solvents including tetrahydrofuran, toluene, chloroform, and 1,4-dioxane. The NT/PPAs are macroscopically processible, and shearing of the NT/PPA solutions readily aligns the nanotubes along the direction of the applied mechanical force. The nanotubes exhibit a strong photostabilization effect, protecting the PPA chains from photodegradation under harsh laser irradiation with incident fluence as high as 10 J/cm(2). The NT/PPA solutions effectively limit intense optical pulses, with the saturation fluence tunable by varying the nanotube contents

THz Photoconductive Antennas for 1.55 µm Telecom Wavelengths

We present low temperature grown InGaAs multiple-quantum well structures which are successfully applied as transmitters and receivers in THz time domain systems. Operation at telecom wavelengths of 1.55µm with a femtosecond fiber laser is demonstrated