Two optical cavities that share one movable mirror can hand a quantum state of light from one to the other without any external control field, because the mirror itself sweeps the two cavity frequencies through an avoided crossing. Keeping the optomechanical coupling nonlinear (rather than linearizing it about a strong pump) and working in the high-amplitude limit, where the mirror carries many quanta, removes the usual need to ground-state cool the oscillator, and lets states with a hundred or more photons - Fock states, Schrodinger cat states, displaced squeezed states - be transferred with fidelity near unity. Learners work through the effective three-mode Hamiltonian, the adiabaticity and weak-optical-coupling conditions that make the resonance sharp, the transmittance matrix that turns population transfer into state fidelity, and why a phase-tracking moving target state removes the rapid fidelity oscillation that a fixed target suffers.
This paper proposes a passive scheme for transferring quantum states of light between two optical cavities that share a common mechanical oscillator, and shows that the scheme works for superposed st…