  We report on high-resolution photoluminescence (PL) spectroscopic and
microscopic study of laterally coupled InAs/GaAs self-assembled quantum dots by
using a low-temperature near-field scanning optical microscope. We have
observed slightly split PL spectra, which are associated with the bonding
(symmetric) and antibonding (antisymmetric) energy states between two coupled
quantum dots, closely located each other as confirmed by spatial mapping of the
PL intensity. The experimental results are in qualitative agreement with the
simple theoretical calculations based on a two-dimensional potential model.
This work may open the way to a simultaneous spectroscopy and microscopy study
of laterally coupled quantum dots in a high-density quantum dot sample without
any articulate sample fabrication.

Materials Science;Other Condensed Matter