Abstract
The nonlinear optical properties of one-dimensional semiconducting polymers such as polydiacetylene and polysilane are discussed on the basis of calculations using a simple tight-binding model with long-range electron-electron interactions. It is demonstrated that the existence of one- dimensional excitons is of primary importance in understanding the linear and nonlinear spectra of these materials. The comparison between theory and experiment allows us to discuss characteristic features of the excitons.
