TERAHERTZ PHOTORESPONSE OF QUANTUM WIRES IN MAGNETIC-FIELDS

We have investigated the terahertz photoresponse of quantum wires in h igh magnetic fields, employing intense far-infrared (FIR) radiation fr om the UCSB Free-Electron Lasers. Both GaAs-based and InAs-based quant um wires, with widths ranging from 50 nm to 1 mu m, were studied. At h igh FIR power we observed Shubnikov-de Haas type oscillations in photo response versus magnetic field, B, resulting from non-resonant electro nic heating; the oscillations were much more pronounced than those in resistance versus B. At low FIR power we observed resonant peaks due t o magnetoplasmon excitations, whose strength shows strong polarization -dependence and whose energy extrapolates to a finite value at zero B. These results provide a powerful tool for characterizing 1D electroni c states in quantum wires. (C) 1996 Academic Press Limited