3,544 research outputs found
Calibrating an interferometric laser frequency stabilization to MHz precision
We report on a calibration procedure that enhances the precision of an
interferometer based frequency stabilization by several orders of magnitude.
For this purpose the frequency deviations of the stabilization are measured
precisely by means of a frequency comb. This allows to implement several
calibration steps that compensate different systematic errors. The resulting
frequency deviation is shown to be less than MHz (rms MHz) in the
whole wavelength interval nm. Wide tuning of a stabilized laser at
this exceptional precision is demonstrated.Comment: http://dx.doi.org/10.1364/AO.51.00551
Quantum dot-photonic crystal chips for quantum information processing
We have recently developed a technique for local, reversible tuning of individual quantum dots on a photonic crystal chip by up to 1.8nm, which overcomes the problem of large quantum dot inhomogeneous broadening - usually considered the main obstacle in employing such platform in practical quantum information processing systems. We have then used this technique to tune single quantum dots into strong coupling with a photonic crystal cavity, and observed strong coupling both in photoluminescence and in resonant light scattering from the system, as needed for several proposals for scalable quantum information networks and quantum computation
Wide frequency tuning of continuous terahertz wave generated by difference frequency mixing under exciton-excitation conditions in a GaAs/AlAs multiple quantum well
Continuous terahertz wave sources with narrow bandwidth and wide frequency tunability enable high-resolution terahertz spectroscopy and high-speed information communication. In this study, using the optical nonlinearity of excitons as the source of second-order nonlinear polarization, we realize a continuous terahertz electromagnetic wave demonstrating wide frequency tunability from 0.1 to 18 THz without a decrease in intensity due to phonon scattering. Because of excitation of two exciton states in a
Ga
As
/
Al
As
multiple quantum well using two continuous-wave lasers, terahertz waves are emitted as a result of difference-frequency mixing, where the intensity shows a square dependence on the excitation intensity. Using the inhomogeneous width of exciton lines, we achieve wide frequency tunability without phonon effects
All-optical wavelength-tunable narrow-linewidth fiber laser
Parameter regulations of narrow-linewidth fiber lasers in frequency domain
has drawn considerable interests for widespread applications in the light
quantum computing, precise coherent detection, and generation of micro-waves.
All-optical methods provide compact, precise and fast accesses to achieving
these lasers with wavelength-tunability. Here, the optical-thermal effects of
graphene is utilized to precisely control operations of free-running lasers
with a tuning speed of 140 MHz/ms. Assisted by the single-longitude-mode
operation and linewidth suppression of stimulated Brillouin backscattering, we
obtain an optical-controllable ~750 Hz fiber laser with a wavelength-tuning
range of 3.7 nm
Mid-infrared quantum optics in silicon
Applied quantum optics stands to revolutionise many aspects of information
technology, provided performance can be maintained when scaled up. Silicon
quantum photonics satisfies the scaling requirements of miniaturisation and
manufacturability, but at 1.55 m it suffers from unacceptable linear and
nonlinear loss. Here we show that, by translating silicon quantum photonics to
the mid-infrared, a new quantum optics platform is created which can
simultaneously maximise manufacturability and miniaturisation, while minimising
loss. We demonstrate the necessary platform components: photon-pair generation,
single-photon detection, and high-visibility quantum interference, all at
wavelengths beyond 2 m. Across various regimes, we observe a maximum net
coincidence rate of 448 12 Hz, a coincidence-to-accidental ratio of 25.7
1.1, and, a net two photon quantum interference visibility of 0.993
0.017. Mid-infrared silicon quantum photonics will bring new quantum
applications within reach.Comment: 8 pages, 4 figures; revised figures, updated discussion in section 3,
typos corrected, added referenc
Measurement and tuning of the chromatic dispersion of a silicon photonic wire around the half band gap spectral region
We demonstrate the measurement and tuning of second-to-fourth order dispersion of a silicon wire waveguide in a spectral region of low nonlinear losses. Using white light interferometry we extract the chromatic dispersion of our waveguide from 1950 to 2300 nm. Moreover we demonstrate tuning of the zero dispersion wavelength over more than 100 nm, pushing it to longer wavelength by partially underetching the waveguide. © 2014 Optical Society of America.info:eu-repo/semantics/publishe
Nonlinear motion and mechanical mixing in as-grown GaAs nanowires
We report nonlinear behavior in the motion of driven nanowire cantilevers.
The nonlinearity can be described by the Duffing equation and is used to
demonstrate mechanical mixing of two distinct excitation frequencies.
Furthermore, we demonstrate that the nonlinearity can be used to amplify a
signal at a frequency close to the mechanical resonance of the nanowire
oscillator. Up to 26 dB of amplitude gain are demonstrated in this way
Optomechanical position detection enhanced by de-amplification using intracavity squeezing
It has been predicted and experimentally demonstrated that by injecting
squeezed light into an optomechanical device it is possible to enhance the
precision of a position measurement. Here, we present a fundamentally different
approach where the squeezing is created directly inside the cavity by a
nonlinear medium. Counterintuitively, the enhancement of the signal to noise
ratio works by de-amplifying precisely the quadrature that is sensitive to the
mechanical motion without losing quantum information. This enhancement works
for systems with a weak optomechanical coupling and/or strong mechanical
damping. This could allow for larger mechanical bandwidth of quantum limited
detectors based on optomechanical devices. Our approach can be
straightforwardly extended to Quantum Non Demolition (QND) qubit detection.Comment: references added, slight change
- …