108 research outputs found
Towards an optical far-field measurement of higher-order multipole contributions to the scattering response of nanoparticles
We experimentally show an all-optical multipolar decomposition of the
lowest-order Eigenmodes of a single gold nanoprism using azimuthally and
radially polarized cylindrical vector beams. By scanning the particle through
these tailored field distributions, the multipolar character of the Eigenmodes
gets encoded into 2D-scanning intensity maps even for higher-order
contributions to the Eigenmode that are too weak to be discerned in the direct
far-field scattering response. This method enables a detailed optical mode
analysis of individual nanoparticles.Comment: 5 pages, 3 figure
Geometric spin Hall effect of light in tightly focused polarization tailored light beams
Recently, it was shown that a non-zero transverse angular momentum manifests
itself in a polarization dependent intensity shift of the barycenter of a
paraxial light beam [A. Aiello et al., Phys. Rev. Lett. 103, 100401 (2009)].
The underlying effect is phenomenologically similar to the spin Hall effect of
light, but does not depend on the specific light-matter interaction and can be
interpreted as a purely geometric effect. Thus, it was named the geometric spin
Hall effect of light. Here, we experimentally investigate the appearance of
this effect in tightly focused vector-beams. We use an experimental
nano-probing technique in combination with a reconstruction algorithm to verify
the relative shifts of the components of the electric energy density in the
focal plane, which are linked to the intensity shift. By that, we
experimentally demonstrate the geometric spin Hall effect of light in a focused
light beam.Comment: 8 pages, 5 figure
The Important Factors of Quality Improvement of Students’ Training, Marketing of Educational Services, and Image of Institutions of Higher Education of Ukraine
The research is aimed at a comparative analysis of the criteria published in 2017 in terms of three ratings of institutions of higher education (IHE) of Ukraine and developing of theoretic-methodical approaches to the detection at macro-, meso- and micro-levels of important factors of quality improvement of students’ training, marketing of educational services, and image of IHE. It is substantiated that corruption should be countered on macro- and meso-levels in every institution of higher education. The publication contains an analysis of the resolution of the Cabinet of Ministers of Ukraine No. 347 of May 10, 2018, which approved the changes, favorable for IHE, but there is no clear order of their implementation. It is substantiated, that for the large-scale improvement of quality of of students’ training together with marketing of educational services it is necessary to considerably increase quality of economic system of the country along with the State regulation of the economy. The author’s own conception of social responsibility of enterprises of all kinds of activity and forms of ownership (including IHE), as well as their marketing, has been improved
Assembling nanostructures from DNA using a composite nanotweezers with a shape memory effect
The article demonstrates a technique for fabricating a structure with the
inclusion of suspended DNA threads and manipulating them using composite
nanotweezers with shape memory effect. This technique could be suitable for
stretching of nanothin DNA-like conductive threads and for measuring their
electrical conductivity, including the I-V characteristic directly in the
electron microscope chamber, where the nanotweezers provide a two-sided
clamping of the DNA tip, giving a stable nanocontact to the DNA bundle. Such
contact, as a part of 1D nanostructure, is more reliable during manipulations
with nanothreads than traditional measurements when a nanothread is touched by
a thin needle, for example, in a scanning tunnel microscope.Comment: To be presented on IEEE 3M-NANO 201
Up from Crisis: Overhauling Healthcare Information, Payment, and Delivery in Extraordinary Times. Dialogue with Featured Speakers from the 6th Annual Connected Health Symposium
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78098/1/tmj.2009.9948.pd
Asymmetric rolling of interstitial-free steel using differential roll diameters. Part II : microstructure and annealing effects
The effects of annealing on the microstructure, texture, tensile properties, and R value evolution of an IF steel sheet after room-temperature symmetric and asymmetric rolling were examined. Simulations were carried out to obtain R values from the experimental textures using the viscoplastic self-consistent polycrystal plasticity model. The investigation revealed the variations in the textures due to annealing and symmetric/asymmetric rolling and showed that the R values correlate strongly with the evolution of the texture. An optimum heat treatment for the balance of strength, ductility, and deep drawability was found to be at 873 K (600 _C) for 30 minutes
A note on biorthogonal ensembles
We consider ensembles of random matrices, known as biorthogonal ensembles,
whose eigenvalue probability density function can be written as a product of
two determinants. These systems are closely related to multiple orthogonal
functions. It is known that the eigenvalue correlation functions of such
ensembles can be written as a determinant of a kernel function. We show that
the kernel is itself an average of a single ratio of characteristic
polynomials. In the same vein, we prove that the type I multiple polynomials
can be expressed as an average of the inverse of a characteristic polynomial.
We finally introduce a new biorthogonal matrix ensemble, namely the chiral
unitary perturbed by a source term.Comment: 20 page
A high-precision near-infrared survey for radial velocity variable low-mass stars using CSHELL and a methane gas cell
We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25-150 Myr) moving groups, the young field star ϵ Eridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8-15 m s-1with a long-term stability of 15-50 m s-1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25-50 m s-1 at ≈2.3125 μm, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ 876 bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD 160934 AB and GJ 725 AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3σ-5σ. Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of ≲5 m s-1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs
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