Time- and frequency-resolved determination of ultrafast energy transfer in optical Kerr measurements

Transient energy transfer effect might occur in femtosecond pump–probe optical Kerr gate (OKG) measurements. Using time- and frequency-resolved two-dimensional pump–probe imaging spectroscopy, we are able to obtain the OKG spectra as a function of the delay time between pump and probe pulses. By analyzing the pump power dependence of the OKG spectra at different delay time, we find that due to the effect of transient energy transfer, the short-wavelength components of the OKG spectra are enhanced when the delay of the probe to pump pulse is positive, while the long-wavelength components increase when the delay is negative.