No Arabic abstract
The coupling of mechanical and optical degrees of freedom via radiation pressure has been a subject of early research in the context of gravitational wave detection. Recent experimental advances have allowed studying for the first time the modifications of mechanical dynamics provided by radiation pressure. This paper reviews the consequences of back-action of light confined in whispering-gallery dielectric micro-cavities, and presents a unified treatment of its two manifestations: notably the parametric instability (parametric amplification) and radiation pressure back-action cooling. Parametric instability offers a novel photonic clock which is driven purely by the pressure of light. In contrast, radiation pressure cooling can surpass existing cryogenic technologies and offers cooling to phonon occupancies below unity and provides a route towards cavity Quantum Optomechanics
Hexagonal boron nitride (hBN) is an emerging layered material that plays a key role in a variety of two-dimensional devices, and has potential applications in nanophotonics and nanomechanics. Here, we demonstrate the first cavity optomechanical system incorporating hBN. Nanomechanical resonators consisting of hBN beams with predicted thickness between 8 nm and 51 nm were fabricated using electron beam induced etching and positioned in the optical nearfield of silicon microdisk cavities. A 160 fm/$sqrt{text{Hz}}$ sensitivity to the hBN nanobeam motion is demonstrated, allowing observation of thermally driven mechanical resonances with frequencies between 1 and 23 MHz, and mechanical quality factors reaching 1100 at room temperature in high vacuum. In addition, the role of air damping is studied via pressure dependent measurements. Our results constitute an important step towards realizing integrated optomechanical circuits employing hBN.
We report dispersive coupling of an optically trapped silica nanoparticle ($143~$nm diameter) to the field of a driven Fabry-Perot cavity in high vacuum ($4.3times 10^{-6}~$mbar). We demonstrate nanometer-level control in positioning the particle with respect to the intensity distribution of the cavity field, which allows access to linear, quadratic and tertiary optomechanical interactions in the resolved sideband regime. We determine all relevant coupling rates of the system, i.e. mechanical and optical losses as well as optomechanical interaction, and obtain a quantum cooperativity of $C_Q = 0.01$. Based on the presented performance the regime of strong cooperativity ($C_Q > 1$) is clearly within reach by further decreasing the mode volume of the cavity.
We report the experimental study of a hybrid quantum solid state system comprising two-level artificial atoms coupled to cavity confined optical and vibrational modes. In this system combining cavity quantum electrodynamics and cavity optomechanics, excitons in quantum wells play the role of the two-level atoms and are strongly coupled to the optical field leading to mixed polariton states. The planar optical microcavities are laterally microstructured, so that polaritons can be confined in wires, 3D traps, and arrays of traps, providing an additional tuning degree of freedom for the polariton energies. Upon increasing the non-resonant laser excitation power, a Bose-Einstein condensation of the polaritons is observed. Optomechanical induced amplification type of experiments with an additional weak laser probe clearly identify the coupling of these Bose-Einstein condensates to 20~GHz breathing-like vibrations confined in the same cavities. With single continuous wave non-resonant laser excitation, and once the laser power overpasses the threshold for Bose-Einstein condensation in trap arrays, mechanical self-oscillation similar to phonon ``lasing is induced with the concomitant observation of Mollow-triplet type mechanical sidebands on the Bose-Einstein condensate emission. High-resolution spectroscopic photoluminescence experiments evidence that these vibrational side-band resolved lines are enhanced when neighboring traps are red-detuned with respect to the BEC emission at overtones of the fundamental 20 GHz breathing mode frequency. These results constitute the first demonstration of coherent cavity polariton optomechanics and pave the way towards a novel type of hybrid devices for quantum technologies, phonon lasers, and phonon-photon bidirectional translators.
We present an integrated optomechanical and electromechanical nanocavity, in which a common mechanical degree of freedom is coupled to an ultrahigh-Q photonic crystal defect cavity and an electrical circuit. The sys- tem allows for wide-range, fast electrical tuning of the optical nanocavity resonances, and for electrical control of optical radiation pressure back-action effects such as mechanical amplification (phonon lasing), cooling, and stiffening. These sort of integrated devices offer a new means to efficiently interconvert weak microwave and optical signals, and are expected to pave the way for a new class of micro-sensors utilizing optomechanical back-action for thermal noise reduction and low-noise optical read-out.
We have designed photonic crystal suspended membranes with optimized optical and mechanical properties for cavity optomechanics. Such resonators sustain vibration modes in the megahertz range with quality factors of a few thousand. Thanks to a two-dimensional square lattice of holes, their reflectivity at normal incidence at 1064 nm reaches values as high as 95%. These two features, combined with the very low mass of the membrane, open the way to the use of such periodic structures as deformable end-mirrors in Fabry-Perot cavities for the investigation of cavity optomechanical effects