A potential experimental system, based on high-stress stoichiometric silicon nitride (${\mathrm{Si}}_3{\mathrm{N}}_4$), is proposed to generate steady-state optomechanical entanglement at room temperature. In the proposed structure, a nanostring interacts dispersively and reactively with a microdisk cavity via the evanescent field. We study the role of both dispersive and reactive couplings in generating optomechanical entanglement, and show that the room-temperature entanglement can be effectively obtained through the dispersive couplings under the reasonable experimental parameters. In particular, in the limits of high temperature ($T$) and high mechanical quality factor ($Q_m$), we find that the logarithmic entanglement depends only on the ratio $T/Q_m$. This indicates that improvements of the material quantity and structure design may lead to more efficient generation of stationary high-temperature entanglement.

• Received 30 December 2010

DOI:https://doi.org/10.1103/PhysRevA.84.032317