| Popis: |
Surface thermal fluctuation spectra are measured to previously unachieved precision, down to three orders of magnitude below the shot noise level. Such precision is achieved through statistical reduction of extraneous noise, including shot noise, using the averaged correlation of measurements. Both height and inclination fluctuations of surface fluctuations are measured for various materials and in the case of liquids, their hydrodynamical understanding is compared to the experimental results at unprecedented levels. They agree well for water, but for oil, deviations are seen at high frequencies, perhaps indicating its more complex underlying physics. Surface thermal fluctuation spectra of complex fluids (such as epoxy), rubber and biological materials have also been measured and have qualitatively diverse behavior. We discuss the physics underlying the various spectra and explain the experimental methods used to obtain them. The measurement is simple, requiring relatively a weak power light source, a short time and a small surface area, so that it should be useful for fluctuation measurements in various fields requiring precision, both within and outside physics. |
