  We review and study the roles of quantum and classical fluctuations in recent
cavity-optomechanical experiments which have now reached the quantum regime
(mechanical phonon occupancy < 1) using resolved sideband laser cooling. In
particular, both the laser noise heating of the mechanical resonator and the
form of the optically transduced mechanical spectra, modified by quantum and
classical laser noise squashing, are derived under various measurement
conditions. Using this theory, we analyze our recent ground-state laser cooling
and motional sideband asymmetry experiments with nanoscale optomechanical
crystal resonators.
