Abstract

How we can overcome the trade-off between the magnitude of nonlinearity and response time of semiconductor is a challenging problem because a resonant excitation for large nonlinearity usually induces a long decay time. Recently, a large enhancement of the degenerate-four-wave mixing (DFWM) for GaAs thin films has been observed for a particular thickness (110 nm).^1,2 As theoretically predicted,⁵ this is due to the resonant enhancement of the internal field with a nano-scale spatial pattern. In this paper, we elucidate that this enhanced response also shows very fast decay, by means of the time-resolved measurements of the three beam DFWM and nonlocal transient response theory.⁴

© 2001 Optical Society of America