  It has previously been shown theoretically that the exchange of linear
momentum between the light field in an optical cavity and a vibrating end
mirror can entangle the electromagnetic field with the vibrational motion of
that mirror. In this paper we consider the rotational analog of this situation
and show that radiation torque can similarly entangle a Laguerre-Gaussian
cavity mode with a rotating end mirror. We examine the mirror-field
entanglement as a function of ambient temperature, radiation detuning and
orbital angular momentum carried by the cavity mode.
