EXTENDED PHASE COHERENCE LENGTH OF EXCITONIC POLARITONS IN A QUANTUM-WELL WAVE-GUIDE

The phase coherence length of excitonic polariton propagation in a waveguide incorporating a single quantum well is numerically evaluated using the correspondence between quantum field and classical electromagnetic field. The phase coherence length of such excitonic polariton propagation is found to be drastically increased to the order of 1 mm. This is achieved by controlling the boundaries of the quantum well and core, resulting in artificial control of the coupling between the exciton and photon fields. Such an extended phase coherence length will make it possible to fabricate new interference devices using polariton propagation.