25aYB-15 Exciton Correlation and Nonlinear Optical Processes

Selvakumar V. Nair, T. Takagahara

R. Tanaś

Pavel Chmela

Salvatore Savasta, Omar Di Stefano, R. Girlanda

Summary form only given. The ultrafast nonlinear optical response of semiconductor-microcavities (SMCs) in the nonperturbative regime is attracting growing interest for exploring fundamental light-matter interactions in many-particle quantum systems, as well as for the future implementations of ultrafast photonic devices. In spite of many investigations, the coherent dynamics of excitonic nonlinear-response in the nonperturbative regime has not been fully understood. Open questions are how strong exciton-cavity coupling affects exciton-exciton (X-X) interactions, and how in turn the X-X correlation influences the nonlinear response of SmCs. We investigate these open questions and show that the nonperturbative regime provides an unprecedented tool for investigating four-particle correlations.We start from the equations for the third order exciton polarization and cavity field describing quantum optical effects and coherent nonlinear optics in SMCs, perform the semiclassical factorization and include multiple scattering processes.

Bolton, Neukirch, D. S. Chemla +2 more

Salvatore Savasta, R. Girlanda

We present a fully quantum mechanical theory for an interacting system of photonsand Coulomb correlated electrons and holes in a semiconductor, using a pertubation series in theexciting laser field. The theory provides microscopic descriptions of nonlinear optical processes insemiconductors related to the electromagnetic field quantization. As an application of the theorywe show that it is possible to transfer the exciton exciton Coulomb correlation to photons, thusproducing pairs of near-gap photons with a high degree of quantum entanglement. The photon pairsemerge from the spontaneous optical decay of biexcitons into two polaritons. The pair intensitycorrelations, calculated in the lowdensity limit for a CuCl slab and for semiconductor microcavities,exhibit quantum features which can be observed by coincidence detection.