In this talk, I will give a (personal) overview of different methods presented in the literature to study lensing of gravitational waves beyond geometric optics. I will examine the validity regimes of these approaches and critically assess their strengths and limitations. I will then focus on a framework developed to investigate the deep wave-optics regime, leveraging techniques from quantum scattering theory while maintaining a full treatment of the wave’s polarization structure. I will demonstrate how this framework can be applied to the study of the phenomenology of triple systems and discuss future directions for extending the applicability of this approach.