Direct optical observations of surface thermal motions at sub-shot noise levels

We measure surface thermal fluctuation spectra of liquids, solids, complex fluids, and biological matter using reflected light measurements down to approximately 10(-17) rad(2)/Hz in inclinations or approximately 10(-29) m(2)/Hz in vertical displacement. The random thermal fluctuations are delineated from random noise at sub-shot noise levels. The principle of the measurement is not limited to surface measurements. The dynamical evolution of the surface properties is also investigated. The measurement time is short, passive, and applicable to a wide variety of surfaces.