Optical absorption in semiconductor nanorings under a lateral terahertz electric field

The optical absorption of GaAs nanorings under dc and ac electric fields with frequency at the terahertz range applied in the plane containing the nanoring is investigated. The excitonic effects are essential to describe even qualitatively the absorption spectra. The applied lateral electric fields change the optical absorption spectra prominently. In the presence of terahertz electric fields, the optical absorption spectra may be very different for different frequencies. In certain frequencies, there arise other absorption peaks in the below-band-gap spectrum. (C) 2005 American Institute of Physics.