Ultrasensitive probing of nonequilibrium thermodynamics at liquid–vapor interfaces using dark hollow beams

Quantifying the thermodynamic properties of liquid–vapor interfaces is crucial for understanding the fundamental physics governing phase transitions and interfacial phenomena. Traditional scattering methods, although effective for remote and noninvasive characterization, face challenges in truly detecting the weak inhomogeneities of thermal origin. We introduce a novel scattering approach that takes advantage of the unique properties of dark hollow beams to not only provide unprecedented sensitivity to temperature variations at liquid–vapor interface, but also simplify the detection of such subtle fluctuations. Our results expand the conventional understanding of interface dynamics by providing experimental means to examine the complex molecular interactions during nonequilibrium thermodynamic processes such as evaporation and condensation. This characterization technique could significantly impact applications in chemical analysis, remote sensing, environmental monitoring, and industrial processes, where simple and robust sensing systems providing accurate real-time data are vital.