Our experimental techniques involve the use of ultrashort pulses of laser light to inject and study spin-polarized electrons in semiconductors. The use of short laser pulses, together with time-correlated excitation techniques such as pump-probe spectroscopy, allows one to monitor the evolution of an injected spin ensemble with a time resolution that is limited only by the pulse duration (60 femtoseconds). In other words, we can take snapshots of the electron's spin state with extremely short time intervals (~10-14 s), providing crucial information about the coherent evolution of the electron spins. These powerful experimental methods also rely on the optical selection rules in III-V semiconductor nanostructures, which permit spin-selective excitation and probing using circularly-polarized light.
We are studying charge and spin dynamics in a wide range of semiconductor materials (quantum wells, quantum dots, diluted magnetic semiconductors) for applications in Spintronics and Quantum Information Science. These experiments are carried out within a pair of state-of-the-art ultrafast laser labs within my group at Dalhousie University. We are equipped with both OPO and OPA tunable laser sources, in addition to a superconducting 7 Telsa optical cryostat, and microscopy cryostat with cryogenic sample nanopositioning capability.hat will be valuable in a number of rapidly advancing high technology areas, including spintronics, photonics and semiconductor device technology. (Picture: reprinted by permission copyright 2003 The Gazette.)