Novel devices and techniques in nonlinear optics.

Abstract

A novel nonlinear frequency conversion technique based on intracavity stimulated Raman scattering in solid-state media is discussed. Devices have been built which are based on this technique. Standard first-order resonator eigenmode routines as well as paraxial diffraction-propagation, laser gain and nonlinear conversion routines have been integrated into a generalized laser resonator design software package which can accurately model the growth and evolution of the transverse field distribution in arbitrary intra- or extra-cavity nonlinear frequency converted laser sources. This package has been implemented as a design tool and has been utilized to model intracavity Raman beam cleanup. The macroscopic and microscopic pulse dynamics are modeled by rate equation and roundtrip pulse intensity iterator routines, respectively. A host of dynamical features are predicted theoretically and confirmed by experiment; such as, nonlinear cavity dumping, gain switching, dynamical chaos, and self-mode-locking. A new theory based on probabilistic arguments is developed to describe the spectral properties of intracavity Raman lasers. It is shown that under normal conditions, the Raman gain profile which results from multimode pumping is inhomogeneously broadened. Questions of efficiency, cavity matching, injection seeding and locking are addressed. Phase-matching and conversion efficiency in optically active second-order nonlinear materials is treated theoretically. Also examined are the conditions under which optical activity significantly alters the nonlinear optical properties of a material and show how this mechanism might be used in designing a nonlinear optical device. Corrections to the standard theoretical expressions for birefringent phase-matching angles and conversion efficiency are obtained for application to biaxial crystals with large natural birefringence. A generalized quasi-phase-matching scheme based on optical activity is formulated for three-wave interactions in second-order nonlinear crystals. A technique based on optical parametric generation and amplification is utilized to accurately determine the dispersion of the nonlinear susceptibilities in thin-film samples. Intrinsic pump-energy instabilities are taken into account in the data analysis.