Quantum motion of a squeezed mechanical oscillator attained via an optomechanical experiment

Abstract

We experimentally investigate a mechanical squeezed state realized in a parametrically modulated membrane resonator embedded in an optical cavity. We demonstrate that a quantum characteristic of the squeezed dynamics can be revealed and quantified even in a moderately warm oscillator, through the analysis of motional sidebands. We provide a theoretical framework for quantitatively interpreting the observations and present an extended comparison with the experiment. A notable result is that the spectral shape of each motional sideband provides a clear signature of a quantum mechanical squeezed state without the necessity of absolute calibrations, in particular in the regime where residual fluctuations in the squeezed quadrature are reduced below the zero-point level.

Active feedback cooling of a SiN membrane resonator by electrostatic actuation

“…44 In that regard, it is worth pointing out that micromechanical resonators as SiN membranes coupled to optical technologies represent a promising platform to test quantum limits of resonant sensors or more in general quantum non-classical behavior in macroscopic objects. 20,21 An important prerequisite for approaching the quantum realm in a resonant device is that it is into its quantum ground state. At any non-zero temperature, there is always a finite probability to find the resonator in an excited state, and the average thermal occupation is 45 n h i % k B T= hω 0 À 1=2.…”

“…16 Moreover, their quality factor remains high in the whole frequency range, so they can be used with optimal efficiency, both in single-mode applications, such as optical cooling, 17 and in multimode applications, such as two-mode squeezing. 18 Recently, they have been embedded in a "membrane-in-the-middle" setup, allowing us to reach a thermal occupation number in the transition region from classical to quantum regime 19 and to reveal, through the analysis of motional sidebands asymmetry measured by heterodyne detection, 20 nonclassical properties in the dynamics of macroscopic oscillators. 21 Here, the feedback was realized by monitoring the thermal motion of the thin membrane (%100 nm) through a highsensitivity optical interferometric readout and the feedback force was applied by means of an electrode electrostatically coupled to the trapped charges on the dielectric SiN membrane.…”

Silicon-nitride nanosensors toward room temperature quantum optomechanics

“…The round membranes with acoustic shield have been successfully used even inside helium flux cryostats, in quantum optomechanics experiments. 10,[31][32][33] Concerning the rectangular membranes with phononic bandgap structure, we have tested the PM-360 sample inside a 48 mm long cavity, in high vacuum at room temperature. We show in Fig.…”

Active feedback cooling of a SiN membrane resonator by electrostatic actuation

“…Moreover, their quality factor remains high in the whole frequency range so they can be used with optimal efficiency, both in singlemode applications, such as optical cooling 17 , and in multimode applications such as two-mode squeezing 18 . Recently they have been embedded in a "membrane-in-the-middle" setup, allowing to reach a thermal occupation number in the transition region from classical to quantum regime 19 and to reveal, through the analysis of motional sidebands asymmetry measured by heterodyne detection 20 , nonclassical properties in the dynamics of macroscopic oscillators 21 .…”