A5026584682- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Advanced MEMS and NEMS Technologies
- Orbital Angular Momentum in Optics
- Force Microscopy Techniques and Applications
- Advanced Fiber Laser Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Electrodynamics and Casimir Effect
- Advanced Thermodynamics and Statistical Mechanics
- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Microfluidic and Bio-sensing Technologies
- Experimental and Theoretical Physics Studies
- Acoustic Wave Resonator Technologies
- Atomic and Subatomic Physics Research
- Coagulation and Flocculation Studies
- Dark Matter and Cosmic Phenomena
- Particle Dynamics in Fluid Flows
- Geophysics and Sensor Technology
- Laser Design and Applications
- Astrophysical Phenomena and Observations
- Spectroscopy and Quantum Chemical Studies
- Analytical Chemistry and Chromatography
- Particle Detector Development and Performance
- Advanced Measurement and Metrology Techniques
University College London
2017-2024
University of Glasgow
2022
University of Florence
2015-2018
Istituto Nazionale di Fisica Nucleare, Sezione di Firenze
2015-2018
Istituto Nazionale di Fisica Nucleare
2012-2017
Istituto Nazionale di Fisica Nucleare, Trento Institute for Fundamental Physics And Applications
2014-2015
University of Trento
2012-2014
Fondazione Bruno Kessler
2008
Istituto di Fotonica e Nanotecnologie
2008
Abstract A minimal observable length is a common feature of theories that aim to merge quantum physics and gravity. Quantum mechanically, this concept associated with nonzero uncertainty in position measurements, which encoded deformed commutation relations. In spite increasing theoretical interest, the subject suffers from complete lack dedicated experiments bounds deformation parameters have just been extrapolated indirect measurements. As recently proposed, low-energy mechanical...
Levitated particles are an ideal tool for measuring weak forces and investigating quantum mechanics in macroscopic objects. Arrays of two or more these have been suggested improving force sensitivity entangling macropscopic In this article, charged, silica nanoparticles, that coupled through their mutual Coulomb repulsion, trapped a Paul trap, the individual masses charges both characterised. We demonstrate sympathetic cooling one nanoparticle via interaction to second which feedback is...
We report the experimental observation of two-mode squeezing in oscillation quadratures a thermal micro-oscillator. This effect is obtained by parametric modulation optical spring cavity optomechanical system. In addition to stationary variance measurements, we describe dynamic behavior regime pulsed excitation, showing an enhanced surpassing 3 dB limit. While present experiment classical regime, our technique can be exploited produce entangled, macroscopic quantum modes.
We report the confinement of an optomechanical micro-oscillator in a squeezed thermal state, obtained by parametric modulation optical spring. propose and implement experimental scheme based on feedback control oscillator, which stabilizes amplified quadrature while leaving orthogonal one unaffected. This technique allows us to surpass -3dB limit noise reduction, associated resonance, with best result -7.4dB. In moderately cooled system, our can be efficiently exploited produce strong...
Collapse models, proposed to explain the absence of quantum superpositions at macroscopic scales, generically predict existence random forces on a massive object. Here, detection levitated particle motion is explored though three different approaches based an optical cavity, tweezer, and electrical readout exploiting SQUID. These are analyzed compared, advantages, drawbacks, technical challenges assessed.
In view of the integration membrane resonators with more complex MEMS structures, we developed a general fabrication procedure for circular shape SiNx membranes using Deep Reactive Ion Etching (DRIE). Large area and high-stress were fabricated used as optomechanical in Michelson interferometer, where Q values up to 1.3 × 106 measured at cryogenic temperatures, Fabry-Pérot cavity, an optical finesse 50000 has been observed.
Optomechanical devices are being harnessed as sensors of ultraweak forces for applications ranging from inertial sensing to the search elusive dark matter. For latter, there is a focus on detection either higher energy single recoils or ultralight, narrow-band sources; directional signal expected. However, possibility searching stochastic stream weak impulses, more generally broadband signal, need not be excluded; with this and other in mind, we apply Gaussian white noise impulses well...
Abstract We describe the construction and characterisation of a nano-oscillator formed by Paul trap. The frequency temperature stability was measured over several days allowing us to identify major sources trap environmental fluctuations. measure an overall 2 ppm h −1 more than 5 via Allan deviation. Importantly, we find that charge on nanoscillator is stable timescale at least two weeks mass oscillator, can be with 3% uncertainty. This allows distinguish between trapping single nanosphere...
Motivated by the current interest in employing quantum sensors on Earth and space to conduct searches for new physics, we provide a perspective suitability of large-mass levitated optomechanical systems observing dark matter signatures. We discuss conservative approaches recoil detection through spectral analysis coherently scattered light, enhancements directional effects due cross-correlation densities, possibility using superpositions mesoscopic test particles measure rare events.
Ponderomotive squeezing of the output light an optical cavity has been recently observed in MHz range two different optomechanical devices. Quadrature becomes particularly useful at lower spectral frequencies, for example gravitational wave interferometers, despite being more sensitive to excess phase and frequency noise. Here we show a phase/frequency noise cancellation mechanism due destructive interference which can facilitate production ponderomotive kHz demonstrate it experimentally...
Measuring a weak force is an important task for micro-mechanical systems, both when using devices as sensitive detectors and, particularly, in experiments of quantum mechanics. The optimal strategy resolving stochastic signal on huge background (typically given by thermal noise) crucial and debated topic, the stability mechanical resonance further, related critical issue. We introduce analyze parametric control optical spring, that allows to stabilize provides phase reference oscillator...
We report on cooling the center-of-mass motion of a nanoparticle due to purely quadratic coupling between its and optical field high finesse cavity. The resulting interaction gives rise Van der Pol nonlinear damping, which is analogous conventional parametric feedback where cavity provides passive without measurement. show experimentally that like energy distribution strongly nonthermal can be controlled by damping As has prominent role in proposed protocols generate deeply nonclassical...
We experimentally investigate a system composed of two levitating nanospheres whose motions are indirectly coupled via coherent scattering in single optical cavity mode. The loaded into double longitudinal tweezer created with lasers at different wavelengths, where chromatic aberration leads to the formation separate trapping sites. achieve strong coupling between each pair modes transverse plane tweezer, as demonstrated by avoided crossings observed when tuning eigenfrequencies motion one...
This work measures dissipation affecting a nano-particle levitated in Paul trap high vacuum. By evaluating the energy power spectral density of resulting low frequency harmonic oscillator, authors spectrally resolve an ultra-narrow linewidth 80 \textmu{}Hz. These measurements are then used to place bounds on two wavefunctions collapse models their dissipative variants, namely continuous spontaneous localization and Di\'osi-Penrose model
We demonstrate the measurement of nanoparticle anisotropy by angularly resolved Rayleigh scattering single optical levitated particles that are oriented in space via trapping light vacuum. This technique is applied to a range particle geometries from perfect spherical nanodroplets octahedral nanocrystals. show this method can resolve shape differences down few nanometers and be both low-damping environments, as demonstrated here, traditional overdamped fluids used tweezers.
The $x$-$y$ motion of a nanosphere levitated in tweezer trap cavity has applications as quantum sensor for the direction ultraweak external forces. backaction optical field rotates orientation modes. An experimental demonstration shows accurate measurement, control, and even suppression change relative to lab frame.
In the context of a recoil damping analysis, we have designed and produced membrane resonator equipped with specific on-chip structure working as "loss shield" for circular membrane. this device vibrations membrane, quality factor $10^7$, reach limit set by intrinsic dissipation in silicon nitride, all modes regardless modal shape, also at low frequency. Guided our theoretical model loss shield, describe design rationale device, which can be used effective replacement commercial resonators...
Cooling the center-of-mass motion is an important tool for levitated optomechanical systems, but it often not clear which method can practically reach lower temperatures a particular experiment. We directly compare parametric and velocity feedback damping methods, are used extensively cooling of single trapped particles in range traps. By performing experiments on same particle, with detection system, we demonstrate that cools oscillator to temperature order magnitude more resilient...
We report on the mechanical losses measured in a “low-deformation mirror” micro-oscillator designed to reduce as much possible strain coating layer and resulting energy dissipation. The deposition of highly reflective has been fully integrated micro-machining process. at cryogenic temperature quality factor up 105 an optical finesse about 4×104, simulations show that device can manage input powers few mW 4.2 K. These features make very promising for quantum optics experiments.
Generating nonclassical states of light by optomechanical coupling depends critically on the mechanical and optical properties micro-oscillators minimization thermal noise. We present an oscillating micromirror with a quality factor $Q=2.6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ at cryogenic temperature finesse 65 000, obtained thanks to innovative approach design control dissipation. predict that, already 4 K input laser power 2 mW, radiation-pressure quantum fluctuations become main...
According to quantum mechanics, if we keep observing a continuous variable generally disturb its evolution. For class of observables, however, it is possible implement so-called nondemolition measurement: by confining the perturbation conjugate variable, observable estimated with arbitrary accuracy, or prepared in well-known state. instance, when light bounces on movable mirror, intensity not perturbed (the effect just seen phase radiation), but radiation pressure allows trace back...
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 fundamental quantum studies.In this work we present a nano-oscillator made highstress round-shaped membrane with an integrated on-chip 3D seismic filter properly designed reduce losses.This oscillator works 200 kHz -5 MHz range features quality factor Q ≃ 10 7 Q-frequency product excess 6.2 × 12 Hz...