924 research outputs found
Proposal for an Optomechanical Traveling Wave Phonon-Photon Translator
In this article we describe a general optomechanical system for converting
photons to phonons in an efficient, and reversible manner. We analyze
classically and quantum mechanically the conversion process and proceed to a
more concrete description of a phonon-photon translator formed from coupled
photonic and phononic crystal planar circuits. Applications of the
phonon-photon translator to RF-microwave photonics and circuit QED, including
proposals utilizing this system for optical wavelength conversion, long-lived
quantum memory and state transfer from optical to superconducting qubits are
considered.Comment: 32 pages, 11 figure
Optomechanics in an ultrahigh-Q two-dimensional photonic crystal cavity
We demonstrate an ultrahigh-Q slotted two-dimensional photonic crystal cavity capable of obtaining strong interaction between the internal light field and the mechanical motion of the slotted structure. The measured optical quality factor is Q = 1.2×10^6 for a cavity with an effective modal volume of V_(eff) = 0.04(λ)^3. Optical transduction of the thermal motion of the fundamental in-plane mechanical resonance of the structure (ν_m = 151 MHz) is performed, from which a zero-point motion optomechanical coupling rate of g∗/2π = 320 kHz is inferred. Dynamical back-action of the optical field on the mechanical motion, resulting in cooling and amplication of the mechanical motion, is also demonstrated
Slot-mode-coupled optomechanical crystals
We present a design methodology and analysis of a cavity optomechanical
system in which a localized GHz frequency mechanical mode of a nanobeam
resonator is evanescently coupled to a high quality factor (Q>10^6) optical
mode of a separate nanobeam optical cavity. Using separate nanobeams provides
flexibility, enabling the independent design and optimization of the optics and
mechanics of the system. In addition, the small gap (approx. 25 nm) between the
two resonators gives rise to a slot mode effect that enables a large zero-point
optomechanical coupling strength to be achieved, with g/2pi > 300 kHz in a
Si3N4 system at 980 nm and g/2pi approx. 900 kHz in a Si system at 1550 nm. The
fact that large coupling strengths to GHz mechanical oscillators can be
achieved in SiN is important, as this material has a broad optical transparency
window, which allows operation throughout the visible and near-infrared. As an
application of this platform, we consider wide-band optical frequency
conversion between 1300 nm and 980 nm, using two optical nanobeam cavities
coupled on either side to the breathing mode of a mechanical nanobeam
resonator
Controlling phonons and photons at the wavelength-scale: silicon photonics meets silicon phononics
Radio-frequency communication systems have long used bulk- and
surface-acoustic-wave devices supporting ultrasonic mechanical waves to
manipulate and sense signals. These devices have greatly improved our ability
to process microwaves by interfacing them to orders-of-magnitude slower and
lower loss mechanical fields. In parallel, long-distance communications have
been dominated by low-loss infrared optical photons. As electrical signal
processing and transmission approaches physical limits imposed by energy
dissipation, optical links are now being actively considered for mobile and
cloud technologies. Thus there is a strong driver for wavelength-scale
mechanical wave or "phononic" circuitry fabricated by scalable semiconductor
processes. With the advent of these circuits, new micro- and nanostructures
that combine electrical, optical and mechanical elements have emerged. In these
devices, such as optomechanical waveguides and resonators, optical photons and
gigahertz phonons are ideally matched to one another as both have wavelengths
on the order of micrometers. The development of phononic circuits has thus
emerged as a vibrant field of research pursued for optical signal processing
and sensing applications as well as emerging quantum technologies. In this
review, we discuss the key physics and figures of merit underpinning this
field. We also summarize the state of the art in nanoscale electro- and
optomechanical systems with a focus on scalable platforms such as silicon.
Finally, we give perspectives on what these new systems may bring and what
challenges they face in the coming years. In particular, we believe hybrid
electro- and optomechanical devices incorporating highly coherent and compact
mechanical elements on a chip have significant untapped potential for
electro-optic modulation, quantum microwave-to-optical photon conversion,
sensing and microwave signal processing.Comment: 26 pages, 5 figure
Influence of monolayer contamination on electric-field-noise heating in ion traps
Electric field noise is a hinderance to the assembly of large scale quantum
computers based on entangled trapped ions. Apart from ubiquitous technical
noise sources, experimental studies of trapped ion heating have revealed
additional limiting contributions to this noise, originating from atomic
processes on the electrode surfaces. In a recent work [A. Safavi-Naini et al.,
Phys. Rev. A 84, 023412 (2011)] we described a microscopic model for this
excess electric field noise, which points a way towards a more systematic
understanding of surface adsorbates as progenitors of electric field jitter
noise. Here, we address the impact of surface monolayer contamination on
adsorbate induced noise processes. By using exact numerical calculations for H
and N atomic monolayers on an Au(111) surface representing opposite extremes of
physisorption and chemisorption, we show that an additional monolayer can
significantly affect the noise power spectrum and either enhance or suppress
the resulting heating rates.Comment: 8 pages, 5 figure
- …