Modal Dispersion Phase Matching appears to be currently much better adapted to parametric mixing in polymeric material waveguides than Quasi Phase Matching. For second harmonic generation at telecommunication wavelengths, using organic materials should allow better performance than with ferroelectric crystals. Promising results are expected in view of theoretical expectations and continuously improving experimental past and current results.

The potential of organic materials for nonlinear optics was recognized early with the identification of charge transfer concepts for second order Materials, and π-electron delocalization in conjugated polymers for third order effects.[l,2] Nevertheless, they have not been seriously considered for applications until the past five years over which applications to electro-optics have been vigorously pursued. At this point many of the relevant technological problems for electro-optics have been faced and solved. This progress has been driven by imminent applications in information processing and communications. Frequency conversion, specifically doubling of near infrared lasers into the blue for data storage etc., also relies on the second order nonlinearities. But progress towards efficient doublers has been dominated by other well-established Materials such as KTP and LiNbO3 because of the short time window perceived for applications.[3,4] However, because of the inherently large nonlinearities associated with organic Materials, one would expect that ultimately the most efficient doubling devices could be made from organic Materials.

Plane-parallel poled, low loss, channel waveguides are fabricated with a large poling field (200V/μm) in 4-dimethylamino-4'-nitrostilbene (DANS) side-chain polymers. The parallel poled film leads to efficient nonlinear optical applications for TE guided Modes. We demonstrate surface emitting second harmonic generation due to mixing of counter propagating waves with this film.

Nonlinear optical phenomena have been investigated over the last three decades in many different materials and a great deal of progress has been made in both the basic science and device applications.(1] Although interest in nonlinear organic materials dates back to the early days of nonlinear optics, it is only in the last five years that progress has been sustained and rapid. The purpose of this paper is to examine progress in developing new nonlinear organic materials and in their application to devices for comparison with current state-of-the-art devices using other material systems.

Using magnetically enhanced dc-triode sputtering we have grown metallic multilayers of Ag/Pd and Cu/Pd with modulation wavelengths A ranging from 10 Å to 120 Å. The Ag/Pd films were prepared with two different thickness ratios of silver to palladium (1:1 and 3:1) while the Cu/Pd films all were 1:1. We observed in the Ag/Pd films that the variation with A of the (111) lattice spacing dav in the growth direction is less than 0.5%, independent of the composition. However, these films exhibited enhancements in the Rayleigh sound velocity vR of up to 22% for the 1:1 samples and 13% for the 3:1 Ag/Pd samples respectively as A decreased. The Cu/Pd films showed a slight systematic dependence of dav on A, although its variation was only approximately 0.7%. A softening in vR of up to 7% for the Cu/Pd samples was observed.

The Rayleigh acoustic waves of sputter-deposited Cu/Co, Ag/Pd and Cu/Pd sup-erlattice films were studied using Brillouin scattering. All three of these systems are fcc/fcc superlattices. The dependence of the Rayleigh wave velocities for these films on the superlattice modulation wavelength is discussed.