Study On The Slow Light Based On Periodically Domain Inverted Ferroelectric Crystal And Their Applications

Slow light, that is, to produce a very small value of the groupvelocity, has attracted significant interest recently for its promisingapplications such as all-optical signal processing, information stor-age, nonlinear optical effects and detection sensitivity enhancement,quantum information processing, phased array radar beam steeringand so on. Perhaps even more significant, from an applications pointof view, is the realization of slow light in a solid that can oper-ate at room temperature. In this thesis, based on the unique physi-cal properties of the periodically domain inverted ferroelectric crys-tal, I investigate numerically and experimentally the slow light phe-nomenons in different schemes which can be listed as follows,The optical properties, especially the quadratic nonlinear opti-cal effect, of periodically domain inverted ferroelectric crystal is thefoundation of our researches. I describe the structure of the typi-cal ferroelectric crystal, lithium niobate, and its waveguide structure.From the quasi-phase-match theory based on this kind of artificialcrystal, I deduce the quadratic nonlinear optical coupling process in-side of it. I also introduce the linear electro-optics effect of lithiumniobate crystal and discuss its optical response to different applied external electric field configuration.I deduce the equations that govern the quadratic cascading in-teraction and investigate the group velocity modulation process ofultrafast pulses. Group velocity control of an ultrashort fundamen-tal frequency (FF) pulse can be achieved, owing to dragging by thegroup velocity mismatched second harmonic (SH) during the phasemismatched SH generation. I describe how different optical or otherphysical parameters determine the performance of the slow and fastlight. Group velocity of input signal over a wide wavelength rangecan be efficiently controlled by introducing the external optical orelectrical field and large fractional time delay can be obtained.I review the function of the photonic crystal for controlling andmanipulating the ?ow of light as well as the coupled-mode theorythat describe the electromagnetic propagation in periodic stratifiedmedia. On that basis, I propose a novel electro-optic photonic crystalutilizing the electro-optics effect of the periodically domain invertedcrystal. I am able to numerically and experimentally demonstratethat the group velocity of a light near the band gap can be delayedvia changes in electric field strength or wavelength.I review the slow light applications in various fields especiallyon spatial compression of optical energy and the enhancement ofnonlinear optical effects. I extend the electro-optic photonic crystalwork to numerically and experimentally study the modulation andenhancement of nonlinear frequency conversion efficiency. Mean-while, I propose and outlook some slow light experiment proposals based on Ti in-diffusion waveguide and artificial photonic crystal.