Dynamic manipulation of nanomechanical resonators in the high-amplitude regime and non-volatile mechanical memory operation

Abstract

Classical and quantum dynamics of nanomechanical systems promise new applications in nanotechnology 18,19 and fundamental tests of quantum mechanics in mesoscopic objects 2,9 . Recent development of nanoscale electromechanical (NEMS) and optomechanical systems has enabled cooling of mechanical systems to their quantum ground state 7,8 , which brings the possibility of quantum information processing with mechanical devices 20,21 . On the other hand, for practical application at room temperature -such as signal processing 22 A rendering of the optomechanical system used in this study is shown in Fig. 1a. ) and yet to allow large oscillation amplitudes. Due to the residual compressive stress introduced by the SOI wafer bonding process, the freestanding doubly clamped beams are slightly buckled and have two stable configurations at rest 37 : buckled up and buckled down (see Fig. 1b). Therefore, the out-of-plane motion of the buckled beam can be described by a double-well potential, where both the 'up'and 'down' states correspond to the minima in the potential. The thermomechanical displacement noise spectra in Fig. 1e show that the two states have slightly different mechanical resonance frequencies, which indicates that the double-well potential is not completely symmetric.The two mechanical states are discriminated in optical transmission measurements because the optical mode has a different effective refractive index in the two states:when the waveguide is closer to the substrate (buckled-down state) the effective refractive index is larger than in the buckled-up state as the optical mode interacts stronger with the substrate. Therefore the optical cavity resonance shifts towards longer wavelengths when the resonator flips from the buckled-up state to the buckled-down state. Consequently, the optical cavity has distinct optical resonances in the two stable configurations as shown in low power optical transmission spectra in Fig. 1c. The low 4 power spectrum probes the static optomechanical resonances, but at high power the mechanical resonator starts to oscillate when the pump wavelength is scanned close to the optical resonance. Fig. 1d shows the optical transmission spectrum measured when the input optical power is well above the threshold for self-sustained oscillations (SSO) of ~600 μW. When the wavelength is scanned across the optical resonance, the transmission no longer shows the low-power Lorentzian shape, rather the resonance is dragged from the "up" to the "down" state: as soon the laser is blue detuned w.r.t. the "up" state, the self-sustained oscillations start and the cavity frequency oscillates back and forth with an amplitude A p-p ·g, where A p-p is the mechanical resonator oscillation amplitude. The SSO in turn modulate the optical transmission at the mechanical oscillation frequency, indicated by the high-frequency components of the optical transmission ( Fig. 1d). The SSO appear in the entire wavelength range between the "up"and "down" state optical modes, which indicates that the energy of th...

Multichannel cavity optomechanics for all-optical amplification of radio frequency signals

“…Cavity optomechanical devices are inherently nonlinear mechanical systems 29 because the optomechanical interaction involves the intra-cavity field, which depends nonlinearly on the mechanical elements' position. Exploiting the nonlinear dynamics in cavity optomechanical systems will be especially important to applications that need to operate the devices in the high-amplitude regime, such as optomechanical oscillators 17,18 and optomechanical memory 19 . As can be seen from equation (1) In the small-amplitude regime, the nonlinear terms are insignificant and only the frequency down shift due to the optical spring k 1 can be observed as in Fig.…”

“…Research in cavity optomechanics exploits the dynamical interplay between the intra-cavity optical field and the mechanical motion of the device, leading to demonstrations of unprecedented phenomena including backaction cooling [10][11][12][13] , normal mode splitting 14 and optomechanically induced transparency 15,16 . Other than fundamental studies, a plethora of promising applications of cavity optomechanics, including tunable photonic filters and wavelength router 5,6 , wavelength conversion and switching 8,9 , radio-frequency optomechanical oscillators 17,18 and non-volatile optical memory 19 , have emerged.…”

Optomechanically induced spontaneous symmetry breaking

“…It has been long known that optomechanical coupling can mimic an effective Kerr-type nonlinearity [29], which can result in classical and quantum nonlinear phenomena such as optical bistability [30] and sub-Poissonian light [31]. Such strong and concentrated nonlinear effects, that can exceed even thermal nonlinearities in strength [32]- [33], paired with a low-noise platform, opens useful applications for light manipulation in nanophotonic devices [34].…”

Squeezing in a coupled two-mode optomechanical system for force sensing below the standard quantum limit

“…However, the radiation pressure coupling between the mechanical mode and optical mode has three consequences: photon shot noise, quantum backaction and dynamical backaction [1,9]. The dynamical backaction modifies the oscillator dynamics [10] and makes laser cooling [11,12] or amplification of phonons [13] in the mechanical system possible. Photon shot noise and quantum backaction, the former decreases with increasing input laser power while the latter increases with increasing input laser power, introduce two sources of noise on the displacement readout of the oscillator motion.…”