ABSTRACT
Two-photon absorption spectroscopy is commonly used as a tool for studying the excited states of molecules and bulk materials. Recently there has been a growing interest in the two-photon absorption process because of its detrimental effects in high-intensity optical device applications. In this chapter, the authors tabulate data from classical two-photon studies and also tabulate upper limits of two-photon absorption coefficients in organic materials that show potential for device applications. The two-photon absorption strength of a molecule is of interest. Such a response is most conveniently represented by the two-photon absorption cross section σ. The authors caution the reader that the two-photon absorption cross section may vary for a molecule in different solvents owing to local field effects.
