Abstract
We study the sample size dependence of the excitonic nonlinear response in the size region beyond the long-wavelength approximation regime. The great enhancement of the nonlinear signal arising from the weakly confined "nondipole-type" excitonic state is demonstrated for a nanoscopic thin film in a particular thickness region. Such peculiar behavior can be explained in terms of the multiple resonance of the internal field and the energy denominator of the susceptibility.