Complete electric field of femtosecond photon echoes at their point of origin

Abstract

Three pulse scattering signals from solutions of the dye IR144 in methanol exhibit a positive chirp that varies with the delay between excitation pulses. Signal emission times, signal spectra, Wigner spectrograms of individual signals, and two dimensional electronic spectra correlating absorption frequency and signal frequency all suggest delayed echo-like signals do not exhibit a significant Stokes' shift.