SEPARATION OF ELECTRONIC AND NUCLEAR CONTRIBUTIONS TO THE THIRD-ORDER NONLINEAR OPTICAL SUSCEPTIBILITIES OF NEW TETRATHIAFULVALENE DERIVATIVES USING DEGENERATE FOUR WAVE MIXING

摘要

We separate the electronic and nuclear contributions to the third-order nonlinear optical susceptibilities . using degenerate four wave mixing. This method allows to know the physical origin of the optical nonlinearities of new soluble tetrathiafulvalene derivatives and deduce the values of the second-order hyperpolarisabilities r. Thevalues of r for the studied com- pounds are about 10s greater than for CS2.