Pliable Polaritons: Wannier Exciton Plasmon Coupling in Metal Semiconductor Structures

Plasmonic structures are known to support the modes with subwavelength volumes in which the field matter interactions are greatly enhanced. Coupling between the molecular excitations and plasmons leading to formation of plexcitons has been investigated for a number of organic molecules. However, plasmon-exciton coupling in metal semiconductor structures have not experienced the same degree of attention. In this work we show that the very strong coupling regime in which the Rabi energy exceeds the exciton binding energy is attainable in semiconductor cladded plasmonic nanoparticles and leads to formation of Wannier Exciton Plasmon Polariton (WEPP) that is bound to the metal nanoparticle and characterized by dramatically smaller (by factor of few) excitonic radius and correspondingly higher ionization energy. This higher ionization energy exceeding approaching 100meV for the CdS/Ag structures may make room temperature Bose Einstein condensation and polariton lasing in plasmonic/semiconductor structures possibl

Fast and slow light in zig-zag microring resonator chains

We analyze fast and slow light transmission in a zig-zag microring resonator chain. This novel device permits the operation in both regimes. In the superluminal case, a new ubiquitous light transmission effect is found whereby the input optical pulse is reproduced in an almost simultaneous manner at the various system outputs. When the input carrier is tuned to a different frequency, the system permits to slow down the propagating optical signal. Between these two extreme cases, the relative delay can be tuned within a broad range

Optimal design and quantum limit for second harmonic generation in semiconductor heterostructures

The optimal design for infrared second harmonic generation (SHG) is determined for a GaAs-based quantum device using a recently developed genetic approach. Both compositional parameters and electric field are simultaneously optimized, and the quantum limit for SHG, set by the trade-off between large dipole moments (favouring electron delocalization) and large overlaps (favouring electron localization), is determined. Optimal devices are generally obtained with an asymmetric double quantum well shape with narrow barriers and a graded region sideways to the largest well. An electric field is not found to lead to improved SHG if compositional parameters are optimized.Comment: 5 pages, 2 figures embedded. To apper in J. App. Phys. (Jan 2nd, 2001