High order frequency conversion in the plasma waveguide

Summary form only given. Nonlinear optics in plasma fibers is distinguished by (1) the unique dispersion properties of the fiber, leading to the wavelength independence of the transverse mode structure; (2) the confinement of extremely high propagating intensities, which gives rise to very high-order nonperturbative processes that can occur with efficiencies comparable to lower order processes; and (3) the dynamic evolution of the plasma waveguide in time, so that the geometric contribution to its dispersion relation is tunable and offers a degree of freedom for phase matching not previously available. We have demonstrated guiding of intensities up to 5/spl times/10/sup 15/ W/cm/sup 2/ in plasma fibers as long as 3 cm. This is well within the range for nonperturbative polarization. Experiments in phase matching and parametric mixing at high intensity are now being performed, using our ability to adjust the waveguide´s length, index depth, and curvature, and the laser pulse´s intensity, width, and wavelength.