Using a Laguerre-Gaussian beam to cool and trap the rotational motion of a mirror

Cavity-enabled optomechanical cooling and trapping of mirrors has lately become experimentally feasible, indicating the possibility of reaching the quantum mechanical ground state of a macroscopic mirror. All theory and experiment so far has been based on the exchange of \textit{linear} momentum between light beams and vibrating mirrors. We consider Laguerre-Gaussian beams carrying \textit{angular} momentum in a cavity made of two highly reflective spiral phase elements. We show that this configuration should enable the optical trapping and cooling of the rotational motion of the movable cavity end-mirror down to its quantum mechanical ground state [1], as well as robust entanglement of its ro-vibrational modes [2]. \newline \newline [1] M. Bhattacharya and P. Meystre, Phys. Rev. Lett. \textbf{99}, 153603-1 (2007). \newline [2] M. Bhattacharya, P.-L. Giscard and P. Meystre, Phys. Rev. Lett. submitted.