Single-beam nearly degenerate frequency technique for waveguide measurements of electronic n (2) , thermal n (2) , α (2) , and four-wave-mixing gain coefficients

We describe a new method that permits the simultaneous measurement of the nonlinear refractive index n(2) and the nonlinear absorption or gain coefficient α(2) The method also permits separate measurement of the fast, electronic n(2) and the slow thermal n(2) Furthermore, the four-wave-mixing coefficient X can be measured with only a slight modification in the experimental setup.