Abstract:
Implementation of quantum communication requires material media that can store and
process information. Recent studies have predicted that at low doping levels (<= 10e14cm(-3))
and low temperatures (<10K) semiconductors have long coherence times and are promising
candidates for studying quantum information processing. Experimental research work
has also found the spin-
flip lifetime (T1) of n-GaAs to be of the order of a millisecond
and has indicated the dependence of T1 on the optical pumping field. In this work, we
perform preparatory experiments with an ensemble of lambda systems formed by donor-bound
electrons in n-GaAs using a polarization maintaining confocal microscope setup
in a He-bath cryostat. We describe in detail, the procedure for finding a homogeneous
ensemble in a sample of GaAs:Si. This work aims towards an optical measurement and
the characterization of the spin-
ip lifetime of the donor-bound electrons, to determine
the dependence on optical pumping parameters. We further describe a Fabry-Perot filter
cavity that has been designed for the detection of weak Raman photons during the
experiment. The design of the cavity has been modified and its performance has been
improved and characterized for the purpose of this experiment.
