Figure: [Left] Illustration of the diffractive lensing of chirping gravitational waves originating from binary merger by “dressed” PBHs in particle DM halos at cosmological distances. Diffractive lensing distorts gravitational wave wavefronts along a broad region of space, which is summed up to produce frequency-dependent amplification of the wave in contrast to the discrete images resulting from geometrical optics lensing. [Right] Frequency dependence of the lensing magnification and phase shift for typical assumed parameters. Characteristic amplification by “dressed” PBH (solid) is exhibiting non-trivial frequency dependence at low-frequency diffraction regimes and illustrates discrimination from a bare PBH without halo (dashed) as well as un-lensed observations (straight dot-dashed). Regimes of geometric optics (GO), transition regime beyond geometric optics (bGO) and weak diffraction (WD) are shown. Figures reproduced from publication.