Degenerate four-wave mixing and Z scan studies of selected transition metal complexes

Materials that exhibit third order nonlinear optical activity are technologically important in the areas of optical power limiting and have potential for all-optical signal processing. The desire to employ these materials as the active element in all-optical devices has led to the search for materials with large, fast third order nonlinearities. In recent years the study of the nonlinear (NLO), optical properties of organic materials has been extended to include metal-organic species. The incorporation of transition metals into conjugated organic systems has been shown to increase the number of easily polarizable electrons, and the presence of low lying charge transfer transitions significantly enhances the nonlinear polarizability of these metal organics when compared to their organic analogs.; In this work the third order NLO properties of selected transition metal organic complexes have been examined by degenerate four wave mixing and by z scan experiments. The primary light source used in this work is a Q-switched Nd:YAG laser. Frequency doubled light from the Nd:YAG was used to perform degenerate four wave mixing at 532 nm. Z scan work was performed at 532 nm and also at the fundamental Nd:YAG wavelength of 1064 nm. The Nd:YAG was also used to pump a wavelength tunable room temperature LiF:F{dollar}sp{lcub}2-{rcub}{dollar} color center laser (CCL), which produced frequency doubled laser light in the wavelength range 550-600 nm. Light from the CCL was used for both z scan and degenerate four wave mixing.; The first portion of this work investigates the nonlinear response of a series of nickel (II) and copper (II) metal-organic complexes. Over the wavelength range 532-600 nm the dominant NLO mechanism for these complexes is shown to be thermal in origin, with a close correlation between the linear absorption and the third order nonlinear response. The next section of this work examines the relationship between structure and third order nonlinear response for a series of platinum (II) and palladium (II) transition metal-organic complexes. The nonlinear response of these materials was shown to be dependent on the quantity of easily polarizable aromatic {dollar}pi{dollar}-electrons, the geometry of the metal-organic complex, and upon the metal atom present in the metal-organic complex.