Ferroelectric Domain Engineering: Controlling Light and Photon at Desire

Abstract

[evdate 2012-10-03] Institute for Advanced Study Distinguished Lecture. Title from event program: Croucher Advanced Study Institute on New Materials and New Concepts for Controlling Light and Waves. Talk no.5.

Abstract: The nonlinear crystals with modulated quadratic nonlinear coefficients X are called quasiphase-matching (QPM) materials, or optical superlattices. The concepts were first referred to by Armstrong et al and Ming et al several decades ago. Berger later extended the QPM from one dimension (1D) to 2D, and proposed the concept of X photonic crystal in order to contrast and compare it with a regular photonic crystal having a periodic linear susceptibility. Since then, such a nonlinear photon crystal has become a very important artificial microstructure material applied to nonlinear optics and laser, in particular, recently in quantum optics. The X photonic crystal is routinely fabricated by pattern-poling a ferroelectric crystal. The sign of X in such a crystal is modulated by reversing the orientation of ferroelectric domain according to some sequence. The motivation for such a modulation is in order to realize a goal that is for either a significant enhancement of nonlinear frequency conversion efficiency by QPM, or a required wavefront of the parametric wave by nonlinear Huggens- Fresnel principle, or for both. In history, the study for the domain modulation in a ferroelectric crystal was extended from 1D to 2D, from periodic to quasi-periodic, aperiodic, even more complicated structure. Many novel nonlinear phenomena, such as third harmonic generation, nonlinear light scattering, nonlinear Cherenkov radiation, nonlinear Talbot effect etc were discovered from such artificially micro- structured materials. Nowadays, ferroelectric domain engineering enters a new regime, quantum optics. The bright entangled photon pairs have been generated from 1D optical superlattice by spontaneously parametric down-conversion. Moreover, the generated entanglement photons could been controlled with full freedom offered by redesigned domain structures in crystals, demonstrating focusing, beam-splitting and other novel effects, which cannot be realized usually in an uniform nonlinear crystal at all. This would bring revolutionary impacts on quantum optics and quantum information in future.

Duration: 39 min.