  A standard quarter-wavelength multilayer optical coating will produce the
highest reflectivity for a given number of coating layers, but in general it
will not yield the lowest thermal noise for a prescribed reflectivity. Coatings
with the layer thicknesses optimized to minimize thermal noise could be useful
in future generation interferometric gravitational wave detectors where coating
thermal noise is expected to limit the sensitivity of the instrument. We
present the results of direct measurements of the thermal noise of a standard
quarter-wavelength coating and a low noise optimized coating. The measurements
indicate a reduction in thermal noise in line with modeling predictions.
