High-sensitivity three-mode optomechanical transducer

Abstract

Three-mode optomechanical interactions have been predicted to allow the creation of very high sensitivity transducers in which very strong optical self-cooling and strong optomechanical quantum entanglement are predicted. Strong coupling is achieved by engineering a transducer in which both the pump laser and a single signal sideband frequency are resonantly enhanced. Here we demonstrate that very high sensitivity can be achieved in a very simple system consisting of a Fabry-Perot cavity with CO 2 laser thermal tuning. We demonstrate a displacement sensitivity of ∼1 × 10 −17 m/ √ Hz, which is sufficient to observe a thermally excited acoustic mode in a 5.6 kg sapphire mirror with a signal-to-noise ratio of more than 20 dB. It is shown that a measurement sensitivity of ∼2 × 10 −20 m/ √ Hz limited by the quantum shot noise is achievable with optimization of the cavity parameters.

High quality factor mg-scale silicon mechanical resonators for 3-mode optoacoustic parametric amplifiers

“…Based on previous cryogenic acoustic loss measurements in bulk silicon, 18 the resonators presented here, if placed in a cryogenic environment, could be expected to achieve quality factors in the range of 10 7 -10 8 . Such values would allow a range of experiments in quantum measurements, tripartite entanglement between photons and phonons 9 and groundstate cooling.…”

“…For this reason, the 3-mode interaction reduces susceptibility to laser phase noise and amplitude noise. 8 The creation of 3-mode parametric amplifiers requires a cavity design in which the mechanical motion of the mirror couples the main laser carrier mode to a transverse mode. For example, an optimal optoacoustic coupling can be achieved by using a torsionally resonant mirror, which has optimal spatial overlap to the TEM 01 optical cavity mode.…”

Radiation pressure excitation of test mass ultrasonic modes via three mode opto-acoustic interactions in a suspended Fabry–Pérot cavity

“…This was reported by Zhao et al [10]. In 2011 thermally excited transverse modes were detected, and three mode interactions were shown to enable high sensitivity spectroscopy of thermally excited acoustic modes [11]. The third component of three mode interactions is the one that closes the feedback loop: radiation pressure excitation via the beating of the carrier with a low amplitude transverse mode.…”

Nonlinearity enhancement in optomechanical systems

“…It has been proved that entanglement of two resonators and of cavity and mirror can be generated by radiation pressure [1][2][3][4], while the pressure can be used to cool down the mirrors [5][6][7][8][9], and the analogous electromagnetically induced transparency phenomenon may happen in a cavity optomechanical system [10][11][12][13] and has been demonstrated in experiment [14]. In addition, optomechanical systems can be used as transducers for long-distance quantum communication [15,16].…”