Experimental observation of elliptical defocusing in the organic material (p-toluene sulfonate)polydiacetylene

Novel, low-power nonlinear self-defocusing has been observed experimentally with the use of the poly-bis-(p-toluene sulfonate) ester of 2,4-hexadiyne-1,6-diol. The strong anisotropy of the material’s thermal conductivity, combined with the high observed thermo-optic coefficient, is shown to cause the phenomenon.