Translator Disclaimer
16 October 1997 Near-infrared spectroscopy of terahertz-driven semiconductor nanostructures
Author Affiliations +
We have explored near-infrared (NIR)--far-infrared (FIR) two-color optical experiments in quantum-confined semiconductor systems, using NIR radiation from a tunable cw Ti:Sapphire laser and intense and coherent FIR radiation from the UCSB Free-Electron Lasers. In this paper two recent experiments are discussed, both of which provide new insight into the internal structure and dynamics of confined excitons: (1) We have observed for the first time FIR internal transitions associated with the direct exciton in GaAs/AlGaAs quantum wells. The spectrum of excitations is enriched by the complexities of the valence band and differ significantly from simple reduced-mass, hydrogenic models. We provide a critical test of detailed calculations including the valence-band mixing of Bauer and Ando. (2) We have discovered resonant nonlinear optical mixing of NIR and FIR radiation, which results in strong near-bandgap emission lines, or optical sidebands. The sidebands appear when optically-created excitons are driven strongly by intense FIR fields. The frequencies of the sidebands are (omega) NIR +/- 2n(omega) FIR, where (omega) NIR is the interband exciton-creation frequency, (omega) FIR is the frequency of the driving field, and n is an integer. The intensity of the sidebands exhibits pronounced resonances as a function of applied magnetic field, which are well- explained in terms of virtual transitions between magnetically-tuned energy levels in the excitons.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Junichiro Kono, Mark Y. Su, Kent B. Nordstrom, J. Cerne, Mark S. Sherwin, S. James Allen Jr., Tohru Noda, T. Inoshita, and Hiroyuki Sakaki "Near-infrared spectroscopy of terahertz-driven semiconductor nanostructures", Proc. SPIE 3153, Accelerator-Based Infrared Sources and Applications, (16 October 1997);

Back to Top