Determining the cubic susceptibility (3) of films or glasses by the Maker fringe method: a representative study of spin-coated films of copper phthalocyanine derivation

An experimental analysis technique is described for accurate extraction of the coherence length and the complex third-order nonlinear susceptibility χ(3) in films or bulk optical glasses from the Maker fringes obtained by third-harmonic generation measurements. This method permits calculation of the third-order susceptibility of a sample without the need for assumptions as to the magnitude or the phase of the nonlinearity relative to a reference material such as the substrate. To illustrate the utility of the method we study spin-coated films of copper 2,3,9,10,16,17,23,24-octa(1,4,7,10-tetraoxaundecyl)phthalocyanine.