Extracting the Nonlinear Response of Buried Interfaces from Electronic Sum-Frequency Generation Data

In this work, several models are used to fit the second-order nonlinear response of a PTCDI-C8/glass interface. The goal was to make these models powerful, interpretable, and extensible, to ensure that other researchers interested in fitting similar data could do so without too much trouble. From the models used, we can see that simple models, such as lorentzians, can be fairly easy to fit; however, they may leave behind interesting information that could otherwise be extracted from the data.