RESUMO
We experimentally demonstrate resonant coupling between photons and excitons in microcavities which can efficiently generate enormous single-pass optical gains approaching 100. This new parametric phenomenon appears as a sharp angular resonance of the incoming pump beam, at which the moving excitonic polaritons undergo very large changes in momentum. Ultrafast stimulated scattering is clearly identified from the exponential dependence on pump intensity. This device utilizes boson amplification induced by stimulated energy relaxation.
RESUMO
A massive redistribution of the polariton occupancy to two specific wave vectors, zero and approximately 3.9x10(4) cm(-1), is observed under conditions of continuous wave excitation of a semiconductor microcavity. The "condensation" of the polaritons to the two specific states arises from stimulated scattering at final state occupancies of order unity. The stimulation phenomena, arising due to the bosonic character of the polariton quasiparticles, occur for conditions of resonant excitation of the lower polariton branch. High energy nonresonant excitation, as in most previous work, instead leads to conventional lasing in the vertical cavity structure.
RESUMO
Coherent excitations of intricate assemblies of molecules play an important role in natural photosynthesis. Microcavities are wavelength-dimension artificial structures in which excitations can be made to couple through their mutual interactions with confined photon modes. Results for microcavities containing two spatially separated cyanine dyes are presented here, where simultaneous strong coupling of the excitations of the individual dyes to a single cavity mode leads to new eigenmodes, described as admixtures of all three states. These "hybrid" exciton-photon structures are of potential interest as model systems in which to study energy capture, storage, and transfer among coherently coupled molecular excitations.
