Speaker: Dirk Bouwmeester, University California, Santa Barbara, USA, and University of Leiden, the Netherlands
In multimode optomechanical systems, the mechanical modes can be coupled via the radiation pressure of the common optical mode, but the fidelity of the state transfer is limited by the optical cavity decay. We demonstrate stimulated Raman adiabatic passage (STIRAP) in optomechanics, where the optical mode is not populated during the coherent state transfer between the mechanical modes, thus avoiding this decay channel. We show a state transfer of a coherent mechanical excitation between vibrational modes of a membrane in a high-finesse optical cavity with a transfer efficiency of 86%. Combined with high mechanical quality factors, STIRAP between mechanical modes can enable generation, storage, and manipulation of long-lived mechanical quantum states, which is important for quantum information science and for the investigation of macroscopic quantum superpositions. A crucial aspect of exploring the quantum regime in optomechanics is the ability to detect individual photons that have been up or down converted in frequency from the optical pump frequency by the absorption or emission of a phonon. This requires a narrow bandwidth optical frequency filter that passes the up or down converted photons while suppressing the pump beam well below the detection-rate of the converted photons. We demonstrate a four coupled cavity filter system that can filter out, with 40% overall detection efficiency, individual photons up or down converted by 1 MHz via optomechanics from a pump source that is 132dB suppressed.