Abstract

Although the dispersion of third-harmonic generation has been used to study the origin of the nonlinearities in conjugated polymers, the fits between experiments and essential state theories have not been unique. To uniquely identify the spectroscopic origin of the third-order susceptibility χ⁽³⁾ we used four different nonlinear spectroscopic techniques. Calculations based on a recently developed quantum anharmonic oscillator theory¹ are in excellent agreement with the experimental nonlinear spectra. This allows us to identify, for the first time to our knowledge, the range of physical parameters and phenomena responsible for optical nonlinearities in conjugated polymers.

© 1993 Optical Society of America