A minimal observable length is a common feature of theories that aim to merge quantum physics and gravity. Quantum mechanically, this concept is associated with a nonzero minimal uncertainty in ...position measurements, which is encoded in deformed commutation relations. In spite of increasing theoretical interest, the subject suffers from the complete lack of dedicated experiments and bounds to the deformation parameters have just been extrapolated from indirect measurements. As recently proposed, low-energy mechanical oscillators could allow to reveal the effect of a modified commutator. Here we analyze the free evolution of high-quality factor micro- and nano-oscillators, spanning a wide range of masses around the Planck mass mP (≈ 22 μg). The direct check against a model of deformed dynamics substantially lowers the previous limits on the parameters quantifying the commutator deformation.
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 <inline-formula> <tex-math notation="LaTeX">Q\simeq 10^{7} </tex-math></inline-formula> and a Q-frequency product in excess of <inline-formula> <tex-math notation="LaTeX">6.2 \times 10^{12} </tex-math></inline-formula> 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. 2018-0186
The problem of the stability of a cavity optomechanical system based on an oscillator having at the same time low optical and mechanical losses is addressed. As it is the aim to extend the use of ...optical squeezing as a tool for improving quantum limited displacement sensing at low frequency, a family of opto‐mechanical devices designed to work at frequencies of about 100 kHz was developed . The devices actually meet the initial design goals, but new requirements have emerged from the analysis of their behavior in optical cavities, due to the interaction between the cavity locking system and the low order normal modes of the devices.
The problem of the stability of a cavity optomechanical system based on an oscillator having at the same time low optical and mechanical losses is addressed. As it is the aim to extend the use of optical squeezing as a tool for improving quantum limited displacement sensing at low frequency, a family of opto‐mechanical devices designed to work at frequencies of about 100 kHz was developed . The devices actually meet the initial design goals, but new requirements have emerged from the analysis of their behavior in optical cavities, due to the interaction between the cavity locking system and the low order normal modes of the devices.
We study the role of stimulated Brillouin scattering in a fiber cavity by numerical simulations and a simple theoretical model and find good agreement between experiment, simulation and theory. We ...also investigate an optomechanical system based on a fiber cavity in the presence on the nonlinear Brillouin scattering. Using simulation and theory, we show that this hybrid optomechanical system increases optomechanical damping for low mechanical resonance frequencies in the unresolved sideband regime. Furthermore, optimal damping occurs for blue detuning in stark contrast to standard optomechanics. We investigate whether this hybrid optomechanical system is capable cooling a mechanical oscillator to the quantum ground state.
Imaging-based detection of the motion of the levitated nanoparticles complements a widely-used interferometric detection method, providing a precise and robust way to estimate the position of the ...particle. Here, we show the camera-based feedback cooling of a charged nanoparticle levitated in a linear Paul trap. A charged nanoparticle levitated in a vacuum was observed by CMOS camera systems. The nanoparticle images were processed in realtime with a microcontroller integrated with a CMOS image sensor. The phase-delayed position signal was fed-back to one of the trap electrodes resulting in the velocity damping cooling. Our study provides a simple and versatile approach applicable for control of low-frequency mechanical oscillators.
We report on strong cooling and orientational control of all translational and angular degrees of freedom of a nanoparticle levitated in an optical trap in high vacuum. The motional cooling and ...control of all six degrees of freedom of a nanoparticle levitated by an optical tweezer is accomplished using coherent elliptic scattering within a high finesse optical cavity. Translational temperatures in the 100 \(\mu\)K range were reached while temperatures as low as 5 mK were attained in the librational degrees of freedom. This work represents an important milestone in controlling all observable degrees of freedom of a levitated particle and opens up future applications in quantum science and the study of single isolated nanoparticles.
Motivated by the current interest in employing quantum sensors on Earth and in space to conduct searches for new physics, we provide a perspective on the suitability of large-mass levitated ...optomechanical systems for observing dark matter signatures. We discuss conservative approaches of recoil detection through spectral analysis of coherently scattered light, enhancements of directional effects due to cross-correlation spectral densities, and the possibility of using quantum superpositions of mesoscopic test particles to measure rare events.
Fast detection and characterization of single nanoparticles such as viruses, airborne aerosols and colloidal particles are considered to be particularly important for medical applications, material ...science and atmospheric physics. In particular, non-intrusive optical characterization, which can be carried out in isolation from other particles, and without the deleterious effects of a substrate or solvent, is seen to be particularly important. Optical characterization via the scattering of light does not require complicated sample preparation and can in principle be carried out in-situ. We describe the characterization of single nanoparticle shape based on the measurement of their rotational and oscillatory motion when optically levitated within vacuum. Using colloidally grown yttrium lithium fluoride nanocrystals of different sizes, trapped in a single-beam optical tweezer, we demonstrate the utility of this method which is in good agreement with simulations of the dynamics. Size differences as small as a few nanometers could be resolved using this technique offering a new optical spectroscopic tool for non-contact characterization of single nanoparticles in the absence of a substrate.
PDF
