Extracting Spectral Diffusion in Two-Dimensional Coherent Spectra via the Projection Slice Theorem

A robust and streamlined method is presented for efficiently extracting spectral diffusion from two-dimensional coherent spectra by employing the projection-slice theorem. The method is based on the optical Bloch equations for a single resonance that include a Frequency-Frequency Correlation Function (FFCF) in the time domain. Through the projection slice theorem (PST), analytical formulation of the diagonal and cross-diagonal projections of time-domain two-dimensional spectra are calculated that include the FFCF for arbitrary inhomogeneity. The time-domain projections are Fourier transformed to provide frequency domain slices that can be fit to slices of experimental spectra. Experimental data is used to validate our lineshape analysis and confirm the need for the inclusion of the FFCF for quantum wells that experience spectral diffusion.