Nonlinear optical wave phenomena observed in defocusing m-cresol/nylon solutions

In this thesis, nonlinear optical wave phenomena are observed using a solution consisting of m-cresol and nylon. The nonlinearity of this material is due to the thermooptic effect, in which light absorption causes a change in the index of refraction - in this case, a reduction in value. Because this change in index of refraction is proportional to the intensity of the light, the nonlinear index of refraction can be modeled as a Kerr-type nonlinearity. In this work, the degree of nonlinearity was quantified in terms of the Kerr coefficient using the z-scan method. We found that this solution exhibited higher nonlinearity as the nylon concentration was increased and that the degree of nonlinearity was orders of magnitude larger than most other reported thermal materials. This thesis also reports experimental results of spatial ID dark optical soliton formation and interaction in this thermal solution. Dark solitons can exist in this material because of its thermal nonlinear properties, which causes light to experience self-phase modulation (SPM) resulting in a defocusing effect. We report the strongest attraction between two ID dark soliton stripes to our knowledge when they were formed in proximity. This attraction can be attributed to the nonlocal effect of thermal diffusion. Finally, we experimentally demonstrate the formation of spatial dispersive shock waves using this highly nonlinear solution. By adjusting the input power of the laser beam, we were able to observe different levels o f the shock formation and wave-breaking through the same sample pathlength.