Quantum nondemolition measurement of optical field fluctuations by optomechanical interaction

Abstract

According to quantum mechanics, if we keep observing a continuous variable we generally disturb its evolution. For a class of observables, however, it is possible to implement a so-called quantum nondemolition measurement: by confining the perturbation to the conjugate variable, the observable is estimated with arbitrary accuracy, or prepared in a well-known state. For instance, when the light bounces on a movable mirror, its intensity is not perturbed (the effect is just seen on the phase of the radiation), but the radiation pressure allows to trace back its fluctuations by observing the mirror motion. In this work, we implement a cavity optomechanical experiment based on an oscillating micro-mirror, and we measure correlations between the output light intensity fluctuations and the mirror motion. We demonstrate that the uncertainty of the former is reduced below the shot noise level determined by the corpuscular nature of light.

Entanglement of propagating optical modes via a mechanical interface

“…We note that equations (2) also closely mirror those describing four-mode squeezing based on the Kerr nonlinearity in glass [21], in which the response function χ m is effectively instantaneous. Both approaches are members of a broader class of settings that enable, in principle, quantum-non-demolition measurements of light [22,23].…”

Cavity optomechanics in a fiber cavity: the role of stimulated Brillouin scattering

“…The tremendous technological advancements over the last few decades have allowed the field to make an impact in both applications and foundational physics. Nowadays, many aspects of the quantum nature of the light-matter interaction have been observed, among these, ground state cooling [1], ponderomotive light squeezing [2,3], and quantum nondemolition measurements of field fluctuations [4]. More recently, levitation of nano-and micro-particles has been gaining more attention, since this platform has entered the quantum regime as well [5,6], furthermore, levitation is considered one of the best candidate to study the quantum to classical transition and collapse models [7,8].…”

Angular trapping of a linear-cavity mirror with an optical torsional spring

“…Suspended pendulums are often used as mechanical oscillators in optomechanical systems over milligram scale [10][11][12][13][14][15][16][17][18][19], while membranes and cantilevers are used in many experiments of smaller mass scales [20][21][22]. Suspended pendulums are advantageous in that they can be isolated from the environment.…”