Two-Dimensional Nonlinear Laser Spectra Calculations with Numerical Path Integral

Two-dimensional three-order nonlinear response functions and the laser spectra of the two-level Frenkel-exciton model, interacting with three short laser pulses in direction ?k₁+k₂+k₃, are calculated using the numerical path integral. The method is non-Markovian and the results show that the numerical simulation scheme provides a new pathway for theoretically investigating the multidimensional ultrafast laser spectra including the non-Markovian effects.