Manipulating the spin polarization of excitons in a single quantum dot by optical means

Circular polarization studies of photoluminescence from the neutral (X(0)) and the positively charged (X(+)) excitons are reported for individual InAs/GaAs quantum dots (QDs). High polarization degrees, 60% for X(0) and 73% for X(+), were recorded without any external magnetic field applied. These studies show that the QD polarization and population dynamics are controllable either by varying the photoexcitation intensity or by using a second IR laser excitation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3554422]