Using a pump-probe laser setup, researchers investigated the interplay between light momentum and fluid mechanics within a two-layer liquid system. They induced a nanometric bulge on the upper liquid layer and observed a transient bulge on the liquid-liquid interface propelled by viscous stress towards the liquid with a higher refractive index. Through noninvasive measurements and extensive numerical simulations, they validated their experimental findings and elucidated the intricate interplay between light momentum theories and fluid mechanics, particularly Minkowski (1908) and M. Abraham (1909).

Furthermore, they demonstrated that the transient deformation height could serve as a valuable indicator of surface tension and viscosity, enabling precise nanoscale manipulation with significant potential for advancements in sensors, actuators, and optical devices. The findings from this study hold substantial promise for the progression of microfluidics and optofluidics. By offering profound insights into the dynamic behavior at the liquid-liquid interface, this research opens avenues for further innovation in these fields. 

The ability to leverage transient deformation height as a diagnostic tool not only enhances our understanding of fluid dynamics but also paves the way for practical applications, driving advancements in sensing technologies and optical manipulation techniques.

This paper, entitled "Probing Interplay of Light Momentum and Fluid Mechanics in Two-layer Liquids", is published in Physical Review Fluids. Congratulations to Gopal, Ashwini, and all co-authors!

Paper link：chttp://dx.doi.org/10.1103/PhysRevFluids.9.034801