  High resolution coherent nonlinear optical spectroscopy of an ensemble of
red-emitting InGaN quantum dots in GaN nanowires is reported. The data show a
pronounced atom-like interaction between resonant laser fields and quantum dot
excitons at low temperature that is difficult to observe in the linear
absorption spectrum due to inhomogeneous broadening from indium fluctuation
effects. We find that the nonlinear signal persists strongly at room
temperature. The robust atom-like room temperature response indicates the
possibility that this material could serve as the platform for proposed
excitonic based applications without the need of cryogenics.
