A Study of Excitation Dynamics of LT-GaAs by Chirp-Controlled Pump-Probe Technique

In this work, a home made chirp-controlled pump-probe measurement system has been developed and the chirp-controlled pump-probe measurement system with temporal resolution of around 100 femtosecond and chirp parameter tuning from --350 fs$^{2}$ to +650 fs$^{2}$ was demonstrated. Meanwhile, using chirp-controlled pump-probe measurement system, ultrafast dynamics of photogenerated carrier in low-temperature growth GaAs in different chirp by was characterized. The shorter relaxation time of low-temperature growth GaAs in positive chirp pump pulse was observed and the result was explained by the Pump-Dump process in negative chirp pump pulse and similar band-filling effect in positive chirp pump pulse.