Long spin relaxation in self-assembled InAIAs quantum dots observed by heterodyne four-wave mixing

摘要

Exciton spin relaxation in self-assembled InAIAs quantum dots was investigated by three-pulse four-wave mixing under resonant conditions. The concept of the spin grating holds well for quantum dots and the measurements combined with optical heterodyne detection at 10 K demonstrates that the exciton spin relaxation lasts up to a few nanoseconds and the time constant is ～5 times larger than the exciton recombination time on average.