Beam Amplification by Transient Energy Transfer in GaAs and Si

Two beam coupling experiments with 29‐ps (FWHM) pulses at a wavelength of 1.06 μm have been performed in GaAs and Si. By optimization of pump‐probe energy ratio, time delay and fluence we obtained optical gain up to 25 in GaAs at a fluence of 35 mJ/cm2 compared to roughly 140 mJ/cm2 required to obtain similar gain in Si.