Method and system for measuring an ultrashort optical pulse

摘要

A method for measuring an ultrashort optical pulse, in which third order autocorrelation of femtosecond (10<-15 >second) optical pulses was realized based on third-harmonic-generation (THG). A THG signal with three fundamental frequency photon contributed from three different split pulses of the ultrashort optical pulse is first generated. The three split pulses have time delays tau1 and tau2 in between. Then, the intensity of the THG signal is detected while varying the time delays tau1 and tau2 between the split pulses to obtain a triple correlation of the ultrashort optical pulse. The triple correlation and its Fourier transform are used to obtain the magnitude |I(nu)| and the phase alpha(nu) of the ultrashort optical pulse intensity in the frequency domain, and the intensity of the ultrashort optical pulse in the time domain I(t) is determined using the magnitude |I(nu)| and the phase alpha(nu) by inverse Fourier Transform.