Pulsewidth dependence of time-resolved two-photon absorption with picosecond pump-probe excitation

Abstract

Pulsewidth dependence of time-resolved two-photon absorption with picosecond pump-probe excitation is investigated. It is shown theoretically that the time-resolved probe transmittance change by two-photon absorption almost follows a temporal autocorrelation of the pump and probe pulses. Time-resolved two-photon absorption measurements of 1.064 μm, 29 ps pulses with semi-insulating undoped GaAs are also performed. The comparison of the experimental results with second harmonic generation autocorrelation measurements confirms the theory.