Accounting for pulse shaper nonlinearity in action-detected two-dimensional electronic spectroscopy

Pulse shapers are widely utilized in two-dimensional (2D) spectroscopy to generate a pump pulse pair with variable time delay and relative carrier-envelope phase. Their use in action-detected 2D spectroscopy has recently garnered interest due to the compatibility with microscopy and potentially higher sensitivity down to the single-molecule level. However, under the conditions necessary for action-detected 2D spectroscopy experiments, pulse shapers are prone to exhibiting nonlinear responses, obscuring the molecular response. Here, we illustrate the potential sources of nonlinearity in an acousto-optic programmable dispersive filter (AOPDF) and demonstrate methods to account for them in data collection and processing, enabling artifact-free action-detected 2D spectroscopy measurements.