2,081 research outputs found
On-chip spectropolarimetry by fingerprinting with random surface arrays of nanoparticles
Optical metasurfaces revolutionized the approach to moulding the propagation
of light by enabling simultaneous control of the light phase, momentum,
amplitude and polarization. Thus, instantaneous spectropolarimetry became
possible by conducting parallel intensity measurements of differently
diffracted optical beams. Various implementations of this very important
functionality have one feature in common - the determination of wavelength
utilizes dispersion of the diffraction angle, requiring tracking the diffracted
beams in space. Realization of on-chip spectropolarimetry calls thereby for
conceptually different approaches. In this work, we demonstrate that random
nanoparticle arrays on metal surfaces, enabling strong multiple scattering of
surface plasmon polaritons (SPPs), produce upon illumination complicated SPP
scattered patterns, whose angular spectra are uniquely determined by the
polarization and wavelength of light, representing thereby spectropolarimetric
fingerprints. Using um-sized circular arrays of randomly distributed
{\mu}m-sized gold nanoparticles (density ~ 75 {\mu}m}) fabricated on
gold films, we measure angular distributions of scattered SPP waves using the
leakage radiation microscopy and find that the angular SPP spectra obtained for
normally incident light beams different in wavelength and/or polarization are
distinctly different. Our approach allows one to realize on-chip
spectropolarimetry by fingerprinting using surface nanostructures fabricated
with simple one-step electron-beam lithography.Comment: 22 pages, 5 figure
Beam-Size Invariant Spectropolarimeters Using Gap-Plasmon Metasurfaces
Metasurfaces enable exceptional control over the light with surface-confined
planar components, offering the fascinating possibility of very dense
integration and miniaturization in photonics. Here, we design, fabricate and
experimentally demonstrate chip-size plasmonic spectropolarimeters for
simultaneous polarization state and wavelength determination.
Spectropolarimeters, consisting of three gap-plasmon phase-gradient
metasurfaces that occupy 120{\deg} circular sectors each, diffract normally
incident light to six predesigned directions, whose azimuthal angles are
proportional to the light wavelength, while contrasts in the corresponding
diffraction intensities provide a direct measure of the incident polarization
state through retrieval of the associated Stokes parameters. The
proof-of-concept 96-{\mu}m-diameter spectropolarimeter operating in the
wavelength range of 750-950nm exhibits the expected polarization selectivity
and high angular dispersion. Moreover, we show that, due to the circular-sector
design, polarization analysis can be conducted for optical beams of different
diameters without prior calibration, demonstrating thereby the beam-size
invariant functionality. The proposed spectropolarimeters are compact,
cost-effective, robust, and promise high-performance real-time polarization and
spectral measurements
Searching for anomalous quartic gauge couplings at muon colliders using principle component analysis
Searching for new physics~(NP) is one of the areas of high-energy physics
that requires the most processing of large amounts of data. At the same time,
quantum computing has huge potential advantages when dealing with large amounts
of data. The principal component analysis~(PCA) algorithm may be one of the
bridges connecting these two aspects. On the one hand, it can be used for
anomaly detection, and on the other hand, there are corresponding quantum
algorithms for PCA. In this paper, we investigate how to use PCA to search for
NP. Taking the example of anomalous quartic gauge couplings in the tri-photon
process at muon colliders, we find that PCA can be used to search for NP.
Compared with the traditional event selection strategy, the expected
constraints on the operator coefficients obtained by PCA based event selection
strategy are even better.Comment: 14 pages, 6 figure
Selection of Guided Surgery Dental Implant Systems Using Network Data Envelopment Analysis
[[abstract]]All dental implant system suppliers typically claim the
advantages and superiority of their product’s specific
attributes and functions. However, as assessment criteria are often inconsistent and conflicting, clinical dentists find it difficult to choose the most appropriate dental implant system.
The present study used two-stage data envelopment analysis to measure the overall efficiency of individual dental implant systems and the relative efficiency of each phase of the selection process. The results of the present study can not only provide decision-making information for users, such as medical organizations, dentists, and patients, but may also inform guidelines for system producers to improve dental implant
performance.[[notice]]補æ£å®Œ
Demand Forecasting for Multichannel Fashion Retailers by Integrating Clustering and Machine Learning Algorithms
[[abstract]]In today’s rapidly changing and highly competitive industrial environment, a new and emerging business model—fast fashion—has started a revolution in the apparel industry. Due to the lack of historical data, constantly changing fashion trends, and product demand uncertainty, accurate demand forecasting is an important and challenging task in the fashion industry. This study integrates k-means clustering (KM), extreme learning machines (ELMs), and support vector regression (SVR) to construct cluster-based KM-ELM and KM-SVR models for demand forecasting in the fashion industry using empirical demand data of physical and virtual channels of a case company to examine the applicability of proposed forecasting models. The research results showed that both the KM-ELM and KM-SVR models are superior to the simple ELM and SVR models. They have higher prediction accuracy, indicating that the integration of clustering analysis can help improve predictions. In addition, the KM-ELM model produces satisfactory results when performing demand forecasting on retailers both with and without physical stores. Compared with other prediction models, it can be the most suitable demand forecasting method for the fashion industry.[[notice]]補æ£å®Œ
A Note on Normal Forms of Quantum States and Separability
We study the normal form of multipartite density matrices. It is shown that
the correlation matrix (CM) separability criterion can be improved from the
normal form we obtained under filtering transformations. Based on CM criterion
the entanglement witness is further constructed in terms of local orthogonal
observables for both bipartite and multipartite systems.Comment: 8 page
Random-phase metasurfaces at optical wavelengths
Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector
Stopping Light on a Defect
Gap solitons are localized nonlinear coherent states which have been shown
both theoretically and experimentally to propagate in periodic structures.
Although theory allows for their propagation at any speed , ,
they have been observed in experiments at speeds of approximately 50% of .
It is of scientific and technological interest to trap gap solitons. We first
introduce an explicit multiparameter family of periodic structures with
localized defects, which support linear defect modes. These linear defect modes
are shown to persist into the nonlinear regime, as {\it nonlinear defect
modes}. Using mathematical analysis and numerical simulations we then
investigate the capture of an incident gap soliton by these defects. The
mechanism of capture of a gap soliton is resonant transfer of its energy to
nonlinear defect modes. We introduce a useful bifurcation diagram from which
information on the parameter regimes of gap soliton capture, reflection and
transmission can be obtained by simple conservation of energy and resonant
energy transfer principles.Comment: 45 pages, Submitted to Journal of the Optical Society
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