Optomechanical coupling of orbital angular momentum with membranes

Optomechanical linear momentum coupling has been demonstrated in classical and quantum regime and in pioneering Beth's experiment the spin part of the photon angular momentum was involved in the manipulation of macroscopic objects. However, Allen etal. in 1992 pointed out the possibility to also transfer orbital angular momentum (OAM) of light to matter. The OAM, unlike spin, can in principle take unlimited values making it attractive in the communication field to potentiality transfer a wealth of information between different nodes of a network. Recently, torsional oscillators have been used to couple and detect optical OAM and optomechanically induced transparency phenomenon in a rotational-cavity have been investigated and proposed for the OAM detection. Here, we propose to exploit optomechanical coupling by using an ultra-low dissipation mechanical silicon nitride membrane, to realize a transducer of orbital angular momentum of light. We couple OAM from optical to mechanical domain by the coupling between a Hermite-Gauss beam (1,1) and the first normal mode of the membranes.