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Weak-value amplification of photon-number operators in the optomechanical interaction
摘要： An experimental proposal is presented in which dark port postselection together with weak measurements are used to enlarge the radiation pressure effect of a single photon on a mechanical oscillator placed in the middle of a Fabry-Pérot cavity and initialized in the ground state. By preparing and postselecting the photon (the system) in two quasiorthogonal states, the weak value of the radiation force operator can lie outside the eigenvalue spectrum, producing a large shift on the wave function of the mechanical oscillator (the measuring device) in the position representation. Consequently, the effect of a single photon on the average position of the oscillator can be amplified as compared to the effect caused by a photon without postselection, i.e., only preselected. The strong measurement scenario is also analyzed. In this case, a higher amplification effect is achieved and the mean position of the oscillator can reach the level of the zero-point fluctuations, but the postselection probabilities are smaller. Finally, the situation in which the oscillator starts in a thermal equilibrium state is studied. In this case, the amplification of the average position remains the same, i.e., proportional to the weak value, but the signal-to-noise ratio is reduced by a factor that depends on the average number of thermal phonons.
关键词： weak measurements,weak-value amplification,optomechanics,postselection,radiation pressure
更新于2025-09-23 15:23:52
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Realizing Q> 300 000 in diamond microdisks for optomechanics via etch optimization
摘要： Nanophotonic structures in single–crystal diamond (SCD) that simultaneously con?ne and co-localize photons and phonons are highly desirable for applications in quantum information science and optomechanics. Here we describe an optimized process for etching SCD microdisk structures designed for optomechanics applications. This process allows the optical quality factor, Q, of these devices to be enhanced by a factor of 4 over previous demonstrations to Q ～ 335 000, which is suf?cient to enable sideband resolved coherent cavity optomechanical experiments. Through analysis of optical loss and backscattering rates, we ?nd that Q remains limited by surface imperfections. We also describe a technique for altering microdisk pedestal geometry which could enable reductions in mechanical dissipation.
关键词： surface roughness,optomechanics,quality factor,etch optimization,diamond microdisks
更新于2025-09-23 15:23:52
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Invited Article: Tuning and stabilization of optomechanical crystal cavities through NEMS integration
摘要： Nanobeam optomechanical crystals, in which localized GHz frequency mechanical modes are coupled to wavelength-scale optical modes, are being employed in a variety of experiments across different material platforms. Here, we demonstrate the electrostatic tuning and stabilization of such devices, by integrating a Si3N4 slot-mode optomechanical crystal cavity with a nanoelectromechanical systems element, which controls the displacement of an additional 'tuning' beam within the optical near-field of the optomechanical cavity. Under DC operation, tuning of the optical cavity wavelength across several optical linewidths with little degradation of the optical quality factor (Q ≈ 105) is observed. The AC response of the tuning mechanism is measured, revealing actuator resonance frequencies in the 10 MHz–20 MHz range, consistent with the predictions from simulations. Feedback control of the optical mode resonance frequency is demonstrated, and alternative actuator geometries are presented.
关键词： optomechanics,tuning,NEMS,cavity optomechanics,stabilization
更新于2025-09-23 15:22:29
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Manipulation of nanomechanical resonator via shaking optical frequency
摘要： Cavity optomechanical system has made rapid advances in the past decades, which is mainly used to study the macroscopic quantum effects of the micromechanical resonators, such as the ground-state cooling of the mechanical resonator, mechanical squeezing, entanglement, macroscopic quantum superposition, etc. Owing to the unique advantages of optomechanical systems, numerous potential applications have been proposed, e.g., the ultrahigh precision metrology, exploring the quantum-classical boundary, and studying the weak signal transducer. The progress of the gravitational-wave detection is a great example for the application of optomechanics. In recent years, the periodically modulated optomechanical systems have attracted significant attention, which have been used to study various macroscopic quantum effects. However, in those modulation proposals, most of them focus on modulating the driven laser field, which results in the first-order moments of the system operators and the effective optomechanical coupling changing periodically to achieve and study some quantum effects. On the other hand, the frequency modulated quantum systems also exhibit a rich behavior and display nonequilibrium properties that are absent in their static counterparts, such as the phenomena of motional averaging and narrowing, Landau–Zener–Stückelberg–Majorana interference, and the formation of dressed states with the appearance of sidebands in the spectrum. However, in cavity optomechanical systems, the study of the influence coming from the frequency modulation is relatively rare to date. In this paper, we study an usual cavity optomechanical system where the frequency of the optical mode is shaken periodically. As we all know, the stability of optomechanical systems is closely related to the effective optomechanical coupling strength. For an excessively large coupling strength, the optomechanical systems are unstable and the studying is also meaningless. However, we find that the shaking optical mode can reduce the effective optomechanical coupling strength arbitrarily when the shaking frequency is much larger than the mechanical resonator frequency, and the deeply physical mechanism can be explained through the Raman-scattering and frequency domain pictures. The result indicates that it will be possible to study the steady quantum effects of optomechanical system even with strong coupling where the standard optomechanical systems without frequency modulation are always unstable. In order to verify the above analyses, we study the ground-state cooling of the mechanical resonator and the entanglement between the optical and mechanical modes in the conventional unstable region, and the results indicate that the final mean phonon number and entanglement not only can be achieved but also can be modulated by the optical shaking parameters. Our proposal provides a method to study the macroscopic quantum effects even in conventional unstable region.
关键词： micromechanical resonator cooling,entanglement,frequency modulation,optomechanics
更新于2025-09-23 15:22:29
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Quantum well photoelastic comb for ultra-high frequency cavity optomechanics
摘要： Optomechanical devices operated at their quantum limit open novel perspectives for the ultrasensitive determination of mass and displacement, and also in the broader field of quantum technologies. The access to higher frequencies implies operation at higher temperatures and stronger immunity to environmental noise. We propose and demonstrate here a new concept of quantum well photoelastic comb for the efficient electrostrictive coupling of light to optomechanical resonances at hundreds of GHz in semiconductor hybrid resonators. A purposely designed ultra-high resolution Raman spectroscopy set-up is exploited to evidence the transfer of spectral weight from the mode at 60 GHz to modes at 190–230 GHz, corresponding to the 8th and 10th overtone of the fundamental breathing mode of the light-sound cavities. The coupling to mechanical frequencies two orders of magnitude larger than alternative approaches is attained without reduction of the optomechanical constant g0. The wavelength dependence of the optomechanical coupling further proves the role of resonant photoelastic interaction, highlighting the potentiality to access strong-coupling regimes. The experimental results show that electrostrictive forces allow for the design of devices optimized to selectively couple to specific mechanical modes. Our proposal opens up exciting opportunities towards the implementation of novel approaches applicable in quantum and ultra-high frequency information technologies.
关键词： semiconductor microcavity,Raman scattering,optomechanics
更新于2025-09-23 15:22:29
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Mimicking a hybrid-optomechanical system using an intrinsic quadratic coupling in conventional optomechanical system
摘要： We consider an optical and mechanical mode interacting through both linear and quadratic dispersive couplings in a general cavity-optomechanical set-up. The parity and strength of an intrinsic quadratic optomechanical coupling (QOC) provides an opportunity to control the optomechanical (OM) interaction. We quantify this interaction by studying normal-mode splitting (NMS) as a function of the QOC's strength. The proposed scheme exhibits NMS features equivalent to a hybrid-OM system containing either an optical parametric amplifier or a Kerr medium. Such a system in reality could offer an alternative platform for devising state-of-art quantum devices with requiring no extra degrees-of-freedom as in hybrid-OM systems.
关键词： Cavity-optomechanics,quadratic optomechanical coupling,normal-mode splitting,resolved side-band regime
更新于2025-09-23 15:22:29
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Optomechanical Kerker Effect
摘要： Tunable directional scattering is of paramount importance for operation of antennas, routing of light, and design of topologically protected optical states. For visible light scattered on a nanoparticle, the directionality could be provided by the Kerker effect, exploiting the interference of electric and magnetic dipole emission patterns. However, magnetic optical resonances in small sub-100-nm particles are relativistically weak. Here, we predict inelastic scattering with the unexpectedly strong tunable directivity up to 5.25 driven by a trembling of a small particle without any magnetic resonance. The proposed optomechanical Kerker effect originates from the vibration-induced multipole conversion. We also put forward an optomechanical spin-Hall effect, the inelastic polarization-dependent directional scattering. Our results uncover an intrinsically multipolar nature of the interaction between light and mechanical motion and apply to a variety of systems from cold atoms to two-dimensional materials to superconducting qubits. An application for engineering of chiral optomechanical coupling and nonreciprocal transmission at nanoscale is proposed.
关键词： Directional scattering,Multipole conversion,Kerker effect,Optomechanics,Spin-Hall effect
更新于2025-09-23 15:22:29
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Optomechanical damping basis
摘要： We present a closed-form analytical solution to the eigenvalue problem of the Liouville operator generating the dissipative dynamics of the standard optomechanical system. The corresponding Lindblad master equation describes the dynamics of a single-mode field inside an optical cavity coupled by radiation pressure to its moving mirror. The optical field and the mirror are in contact with separate environments, which are assumed at zero and finite temperature, respectively. The optomechanical damping basis refers to the exact set of eigenvectors of the generator that, together with the exact eigenvalues, are explicitly derived. Both the weak- and the strong-coupling regime, which includes combined decay mechanisms, are solved in this work.
关键词： Open quantum systems,Decoherence,Optomechanics
更新于2025-09-23 15:22:29
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Silicon Nitride MOMS Oscillator for Room Temperature Quantum Optomechanics
摘要： Optomechanical SiN nano-oscillators in high-finesse Fabry–Perot cavities can be used to investigate the interaction between mechanical and optical degree of freedom for ultra-sensitive metrology and fundamental quantum mechanical studies. In this paper, we present a nano-oscillator made of a high-stress round-shaped SiN membrane with an integrated on-chip 3-D acoustic shield properly designed to reduce mechanical losses. This oscillator works in the range of 200 kHz to 5 MHz and features a mechanical quality factor of Q ≈ 107 and a Q-frequency product in excess of 6.2 × 1012 Hz at room temperature, fulfilling the minimum requirement for quantum ground-state cooling of the oscillator in an optomechanical cavity. The device is obtained by MEMS deep reactive-ion etching (DRIE) bulk micromachining with a two-side silicon processing on a silicon-on-insulator wafer. The microfabrication process is quite flexible such that additional layers could be deposited over the SiN membrane before the DRIE steps, if required for a sensing application. Therefore, such oscillator is a promising candidate for quantum sensing applications in the context of the emerging field of quantum technologies.
关键词： reactive ion etching,MOMS oscillator,quantum optomechanics,SiN thin membrane
更新于2025-09-23 15:21:21
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Atomic swap gate, driven by position fluctuations, in dispersive cavity optomechanics
摘要： Tracing the dynamics of a quantum system using a mesoscopic device is an important topic of interest nowadays. Here we show how a mesoscopic mechanical oscillator can be used to steer the dynamics of a coupled two-atom system and thereby to implement a two-qubit universal gate. We have theoretically studied a generic hybrid atom-optomechanical system where two identical atoms in Λ configuration are trapped inside the cavity and the cavity mode mediates the interaction between the atoms and the mechanical oscillator. Adiabatic elimination of the lossy channels, namely, cavity decay and spontaneous emission, is adopted to obtain an effective Hamiltonian. This Hamiltonian is responsible for two-atom swap and √SWAP gates, controlled by the position fluctuation of the oscillator. The validity of the proposal for successful implementation is assessed using presently available experimental parameters.
关键词： quantum gate,trapped atoms,quantum fluctuations,Cavity optomechanics
更新于2025-09-23 15:21:21