An exciton is the condensed matter analogue of a hydrogen atom. It consists of an electron-hole pair inside a semiconductor, bound together by their mutual coulomb attraction, forming a boson-like quasi particle.

We study two dimensional excitons in GaAs coupled quantum wells (QW), also known as bilayers structures. An externally applied electric field using micro-engineered electrical gates results in the creation of photo-generated indirect excitons, with their electron and hole constituents separated into two layers. These excitons have increased life time, elevated quantum degeneracy temperatures, and all carry dipole moment oriented perpendicular to the QW plane. Such systems posses several distinct properties that make them worthwhile studying: the excitons can be transformed back into light signals in an almost perfect on/off controlled fashion by switching the external electric fields, which can also be used to manipulate their flow. In addition, they interact with each other via the repulsive dipole-dipole potential. Thus, exciton based systems can be viewed as a model for exploring quantum-fluids hydrodynamics* and also be used for novel optoelectronic devices.

We demonstrate an all-optical flow-switch device concept, which combines all of the above physics. The exciton fluid is confined into a one dimensional channel, made by a micro-fabricated electric gate on top of the sample. It is driven along the channel via the interaction with the applied field gradient. The fluid propagation can then be suppressed through remote interaction with other dipolar exciton fluids, optically excited and confined inside electrostatic traps in proximity to the channel.