Pandari Mishra

We report that nanometric axisymmetric surface deformations probed near the onset of total internal reflection produce a strongly anisotropic phase response. The local surface slope modifies the incidence angle, and the steep angular dependence of the Fresnel reflection phase near the critical angle converts these slope variations into measurable phase modulation. As a result, an axisymmetric bulge or dimple generates elliptical interference fringes aligned with the plane of incidence.

We present an experimental setup that utilizes a pump-probe laser configuration to investigate the interplay between light momentum and fluid mechanics in a two-layer liquid system. By inducing a nanometric bulge on the upper liquid layer, we observe the emergence of a transient bulge on the liquid-liquid interface propelled by viscous stress towards the liquid with a higher refractive index.

Air-water interface deformation has been used as a testbed to resolve the momentum of light debate (Abraham-Minkowski) inside the dielectric medium, but to date, experiments or theory which have resolved this debate precisely are lacking. Here, we present the experimental observation of both momenta in a single setup.