Ue-Li Pen, a physicist at the University of Toronto, presents work on wave optics effects in gravitational lensing as they apply to two very different signals: gravitational waves and fast radio bursts. Delivered at the MPG-IAS-NTU Center kick-off conference in Wolfensohn Hall, the talk addresses how wave optics, rather than the usual geometric optics approximation, lets astronomers infer the presence and properties of lensing structures along the path of these signals. Pen brings in the mathematical technique of resurgence, used to extract physical information from divergent or asymptotic series that arise in these lensing calculations. The talk is aimed at researchers working on multimessenger astrophysics, connecting gravitational wave observatories and radio telescopes to questions about dark matter substructure and compact lensing objects. It runs about forty minutes and assumes familiarity with wave propagation and basic lensing theory.