Investigation of Correlation Effects in Nonlinear Optics

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.

Sergei A. Akhmanov, A. S. Chirkin

Makoto Tomita

The coherence-coupling effect in a space- and time-resolved, nonlinear-correlation measurement in a multiple-scattering medium was investigated. In this measurement, two laser beams are injected into the medium, and the total nonlinear optical signal is measured as a function of the relative time delay, spatial separation, and frequency and wave-vector differences between the two beams. Besides the general importance of the nonlinear-correlation measurement, the coherence-coupling effect is interesting because it could provide a novel method of investigating the fluctuations and the correlation effects inside the multiple-scattering medium. We examined the form factor of the coherence-coupling effect as a function of the frequency and wave-vector differences between the two beams.

Jan Peřina

Аникеев Борис Васильевич, D. V. Sin'ko

A method for investigating the photorefractive effect in electro-optical crystals by intracavity spectroscopy, proposed earlier by the authors, is generalised to several other nonlinear optical effects. An analysis is made of the feasibility of measuring the characteristics of nonlinear optical media in which several quantum transitions with different lifetimes can take place. The effectiveness of the method is demonstrated by an investigation of a DKDP crystal at room temperature.