Anisotropic Exciton Rabi Oscillation in Single Telecommunication-Band Quantum Dot

Anisotropic Rabi oscillation in the exciton state in a single InAs/GaAs quantum dot (QD) was demonstrated in the telecommunication-band by selecting two orthogonal polarization angles of the excitation laser. Our InAs QDs were embedded in an intrinsic layer of an n-i-Schottky diode, which provides an electric field to extract photoexcited carriers from QDs. Owing to the potential anisotropy of QDs, the fine structure splitting (FSS) energy in the exciton state in single InAs QDs was similar to 110 mu eV, measured by polarization-resolved photocurrent spectroscopy. The ratio between two different Rabi frequencies, which reflect anisotropic dipole moments of two orthogonal exciton states, was estimated to be similar to 1.2. This demonstrates that the selective control of two orthogonal polarized exciton states is a promising technique for exciton-based-quantum information devices compatible with fiber optics. (C) 2010 The Japan Society of Applied Physics