  We apply the formalism of quantum estimation theory to extract information
about potential collapse mechanisms of the continuous spontaneous localisation
(CSL) form. In order to estimate the strength with which the field responsible
for the CSL mechanism couples to massive systems, we consider the
optomechanical interaction between a mechanical resonator and a cavity field.
Our estimation strategy passes through the probing of either the state of the
oscillator or that of the electromagnetic field that drives its motion. In
particular, we concentrate on all-optical measurements, such as homodyne and
heterodyne measurements. We also compare the performances of such strategies
with those of a spin-assisted optomechanical system, where the estimation of
the CSL parameter is performed through time-gated spin-like measurements.

Quantum Physics