Oriented polaritons in strongly-coupled asymmetric double quantum well   microcavities
  Replacing independent single quantum wells inside a strongly-coupled semiconductor microcavity with double quantum wells produces a special type of polariton. Using asymmetric double quantum wells in devices processed into mesas allows the alignment of the electron levels to be voltage-tuned. At the resonant electronic tunnelling condition, we demonstrate that `oriented polaritons' are formed, which possess greatly enhanced dipole moments. Since the polariton-polariton scattering rate depends on this dipole moment, such devices could reach polariton lasing, condensation and optical nonlinearities at much lower threshold powers. 
Gabriel Christmann, Alexis Askitopoulos, George Deligeorgis, Zacharias   Hatzopoulos, Simeon I. Tsintzos, Pavlos G. Savvidis...
cond-mat.other