  We present first results from a number of experiments conducted on a 0.53 kg
cylindrical dumbbell-shaped sapphire crystal. This is the first reported
optomechanical experiment of this nature utilising a novel modification to the
typical cylindrical architecture. Mechanical motion of the crystal structure
alters the dimensions of the crystal, and the induced strain changes the
permittivity. These two effects result in parametric frequency modulation of
resonant microwave whispering gallery modes that are simultaneously excited
within the crystal. A novel low-noise microwave readout system is implemented
allowing extremely low noise measurements of this frequency modulation near our
modes of interest, having a phase noise floor of -165 dBc/Hz at 100 kHz.
Fine-tuning of the crystal's suspension has allowed for the optimisation of
mechanical quality factors in preparation for cryogenic experiments, with a
value of Q=8 x 10^7 achieved at 127 kHz. This results in a Q x f product of
10^13, equivalent to the best measured values in a macroscopic sapphire
mechanical system. Results are presented that demonstrate the excitation of
mechanical modes via radiation pressure force, allowing an experimental method
of determining the transducer's displacement sensitivity df/dx, and calibrating
the system. Finally, we demonstrate parametric back-action phenomenon within
the system. These are all important steps towards the overall goal of the
experiment; to cool a macroscopic device to the quantum ground state at
millikelvin temperatures.
