Dynamics and Fourier transform studies of the excitonic optical Stark effect

The authors study the optical Stark effect on the exciton of bulk gallium arsenide using high-repetition-rate femtosecond laser pulses. They distinguish three regimes: quasi-permanent, dynamic, and nonadiabatic. In the dynamic case they develop and demonstrate experimentally a technique of dynamics measurement based on the Fourier transform of the absorption spectra. This method has the advantages of being single-shot, of discriminating between a shift and an absorption strength change, and of separating the contribution of a single narrow line from the other spectral components