  Entanglement generation at a macroscopic scale offers an exciting avenue to
develop new quantum technologies and study fundamental physics on a tabletop.
Cavity quantum optomechanics provides an ideal platform to generate and exploit
such phenomena owing to the precision of quantum optics combined with recent
experimental advances in optomechanical devices. In this work, we propose
schemes operating outside the resolved-sideband regime, to prepare and verify
both optical-mechanical and mechanical-mechanical entanglement. Our schemes
employ pulsed interactions with a duration much less than the mechanical period
and, together with homodyne measurements, can both generate and characterize
these types of entanglement. To improve the performance of our schemes, a
precooling stage comprising prior pulses can be utilized to increase the amount
of entanglement prepared, and local optical squeezers may be used to provide
resilience against open-system dynamics. The entanglement generated by our
schemes is quantified using the logarithmic negativity and is analysed with
respect to the strength of the pulsed optomechanical interactions for realistic
experimental scenarios including mechanical decoherence and optical loss. Two
separate schemes for mechanical entanglement generation are introduced and
compared: one scheme based on an optical interferometric design, and the other
comprising sequential optomechanical interactions. The pulsed nature of our
protocols provides more direct access to these quantum correlations in the time
domain, with applications including quantum metrology and tests of quantum
decoherence. By considering a parameter set based on recent experiments, the
feasibility to generate significant entanglement with our schemes, even with
large optical losses, is demonstrated.
