Quantitative line shape analysis for arbitrary inhomogeneity in two-dimensional coherent spectroscopy

Two-dimensional coherent spectroscopy (2DCS) provides simultaneous measurement of homogeneous and inhomogeneous linewidths through quantitative line shape analysis. However, conventional line shape analysis methods assume Gaussian inhomogeneity, limiting its applicability to systems with non-Gaussian inhomogeneity. We present a quantitative line shape analysis method incorporating arbitrary inhomogeneity using a bivariate spectral distribution function in 2DCS simulations. An algorithm is developed to extract the homogeneous linewidth and arbitrary inhomogeneous distribution from an experimentally measured 2D spectrum. We demonstrate this framework for a quantum-well (QW)-exciton resonance with non-Gaussian inhomogeneity. This work broadens the scope of quantitative line shape analysis for studying materials with non-Gaussian inhomogeneity.