A Miniature Laser Interferometer for Noninvasive Viscometry
The University of Northern Iowa, US
Keywords: Interferometer, laser, capillary waves, viscosity
A miniature laser interferometer consisting entirely of an optical fiber held in close proximity
to a fluid surface is described. The total path difference in this interferometer is less than a
millimeter. The interferometer may be used to measure, for example, the amplitude of
submicron capillary waves with a resolution of about 10 nm. In one application the
interfermeter is used to measure, noninvasively, the amplitude decay of capillary waves as
a function of the distance from the wave generator. The amplitude decay data yields the
viscosity of the fluid with unprecedented precision. As a test case, the viscosity of pure water
as a funtion of temperature, measured by this system, will be presented.
 F. Behroozi, B. Lambert, and B. Buhrow, Applied Physics Letters 78, 2399 (2001).
NSTI Nanotech 2003 Conference Technical Program Abstract