101 research outputs found
Generation of Caustics and Spatial Rogue Waves from Nonlinear Instability
Caustics are natural phenomena in which nature concentrates the energy of
waves. Although, they are known mostly in optics, caustics are intrinsic to all
wave phenomena. For example, studies show that fluctuations in the profile of
an ocean floor can generate random caustics and focus the energy of tsunami
waves. Caustics share many similarities to rogue waves, as they both exhibit
heavy-tailed distribution, i.e. an overpopulation of large events. Linear
Schr\"odinger-type equations are usually used to explain the wave dynamics of
caustics. However, in that the wave amplitude increases dramatically in
caustics, nonlinearity is inevitable in many systems. In this Letter, we
investigate the effect of nonlinearity on the formation of optical caustics. We
show experimentally that, in contrast to linear systems, even small phase
fluctuations can generate strong caustics upon nonlinear propagation. We
simulated our experiment based on the nonlinear Schr\"odinger equation (NLSE)
with Kerr-type nonlinearity, which describes the wave dynamics not only in
optics, but also in some other physical systems such as oceans. Therefore, our
results may also aid our understanding of ocean phenomena.Comment: 5 pages, 4 figure
Quantum orbital angular momentum of elliptically-symmetric light
We present a quantum mechanical analysis of the orbital angular momentum of a
class of recently discovered elliptically-symmetric stable light fields --- the
so-called Ince-Gauss modes. We study, in a fully quantum formalism, how the
orbital angular momentum of these beams varies with their ellipticity and
discover several compelling features, including: non-monotonic behavior, stable
beams with real continuous (non-integer) orbital angular momenta, and
orthogonal modes with the same orbital angular momenta. We explore, and explain
in detail, the reasons for this behavior. These features may have application
to quantum key distribution, atom trapping, and quantum informatics in general
--- as the ellipticity opens up a new way of navigating the photonic Hilbert
space.Comment: 9 Pages, 4 Figures, Comments Welcom
Correlation between ileal digestibility of amino acids and chemical composition of soybean meals in broilers at 21 days of age
The correlations between chemical composition and coefficient of standardized ileal digestibility (CSID) of crude protein (CP) and amino acids (AA) were determined in 22 soybean meal (SBM) samples originated from USA (n = 8), Brazil (BRA; n = 7) and Argentina (ARG; n = 7) in 21-day old broilers. Birds were fed a commercial maize-SBM diet from 1 to 17 days of age followed by the experimental diets in which the SBM tested was the only source of protein (205 g CP/kg) for three days. Also, in vitro nitrogen (N) digestion study was conducted with these samples using the two-step enzymatic method. The coefficient of apparent ileal digestibility (CAID) of the SBM, independent of the origin, varied from 0.820 to 0.880 for CP, 0.850 to 0.905 for lysine (Lys), 0.859 to 0.907 for methionine (Met) and 0.664 to 0.750 for cysteine (Cys). The corresponding CSID values varied from 0.850 to 0.966 for CP, 0.891 to 0.940 for Lys, 0.931 to 0.970 for Met and 0.786 to 0.855 for Cys. The CSID of CP and Lys of the SBM were positively correlated with CP (r = 0.514; P menor que 0.05 and r = 0.370; P = 0.09, respectively), KOH solubility (KOH sol.) (r = 0.696; P menor que 0.001 and r = 0.619; P menor que 0.01, respectively), trypsin inhibitor activity (TIA) (r = 0.541; P menor que 0.01 and r = 0.416; P = 0.05, respectively) and reactive Lys (r = 0.563; P menor que 0.01 and r = 0.486; P menor que 0.05) values, but no relation was observed with neutral detergent fiber and oligosaccharide content. No relation between the CSID of CP determined in vivo and N digestibility determined in vitro was found. The CSID of most key AA were higher for the USA and the BRA meals than for the ARG meals. For Lys, the CSID was 0.921, 0.919 and 0.908 (P menor que 0.05) and for Cys 0.828, 0.833 and 0.800 (P menor que 0.01) for USA, BRA and ARG meals, respectively. It is concluded that under the conditions of this experiment, the CSID of CP and Lys increased with CP content, KOH sol., TIA and reactive Lys values of the SBM. The CSID of most limiting AA, including Lys and Cys, were higher for USA and BRA meals than for ARG meals
Phase-Matched Second-Harmonic Generation from Metasurfaces Inside Multipass Cells
We demonstrate a simple and scalable approach to increase conversion
efficiencies of nonlinear metasurfaces by incorporating them into multipass
cells and by letting the pump beam to interact with the metasurfaces multiple
times. We experimentally show that by metasurface design, the associated
phase-matching criteria can be fulfilled. As a proof of principle, we achieve
phase matching of second-harmonic generation (SHG) using a metasurface
consisting of aluminium nanoparticles deposited on a glass substrate. The
phase-matching condition is verified to be achieved by measuring superlinear
dependence of the detected SHG as a function of number of passes. We measure an
order of magnitude enhancement in the SHG signal when the incident pump
traverses the metasurface up to 9 passes. Results are found to agree well with
a simple model developed to estimate the generated SHG signals. We also discuss
strategies to further scale-up the nonlinear signal generation. Our approach
provides a clear pathway to enhance nonlinear optical responses of
metasurface-based devices. The generic nature of our approach holds promise for
diverse applications in nonlinear optics and photonics
Spectral Vector Beams for High-Speed Spectroscopic Measurements
Structured light harnessing multiple degrees of freedom has become a powerful
approach to use complex states of light in fundamental studies and
applications. Here, we investigate the light field of an ultrafast laser beam
with a wavelength-depended polarization state, a beam we term spectral vector
beam. We demonstrate a simple technique to generate and tune such structured
beams and demonstrate their spectroscopic capabilities. By only measuring the
polarization state using fast photodetectors, it is possible to track
pulse-to-pulse changes in the frequency spectrum caused by, e.g. narrowband
transmission or absorption. In our experiments, we reach read-out rates of
around 6 MHz, which is limited by our technical ability to modulate the
spectrum and can in principle reach GHz read-out rates. In simulations we
extend the spectral range to more than 1000 nm by using a supercontinuum light
source, thereby paving the way to various applications requiring high-speed
spectroscopic measurements.Comment: 11 pages, 12 figure
Differences among origins on nutritional and quality parameters of soybean meal
Soybean meal (SBM) is the main protein source in livestock feeds. United States (USA), Brazil (BRA), and Argentine (ARG) are the major SBM exporter countries. The nutritive value of SBM varies because genetics, environment, farming conditions, and processing of the beans influence strongly the content and availability of major nutrients. The present research was conducted to determine the influence of origin (USA, BRA and ARG) on nutritive value and protein quality of SBM
Relational Particle Models. II. Use as toy models for quantum geometrodynamics
Relational particle models are employed as toy models for the study of the
Problem of Time in quantum geometrodynamics. These models' analogue of the thin
sandwich is resolved. It is argued that the relative configuration space and
shape space of these models are close analogues from various perspectives of
superspace and conformal superspace respectively. The geometry of these spaces
and quantization thereupon is presented. A quantity that is frozen in the scale
invariant relational particle model is demonstrated to be an internal time in a
certain portion of the relational particle reformulation of Newtonian
mechanics. The semiclassical approach for these models is studied as an
emergent time resolution for these models, as are consistent records
approaches.Comment: Replaced with published version. Minor changes only; 1 reference
correcte
Deterministic Ultracold Ion Source targeting the Heisenberg Limit
The major challenges to fabricate quantum processors and future nano solid
state devices are material modification techniques with nanometre resolution
and suppression of statistical fluctuations of dopants or qubit carriers. Based
on a segmented ion trap with mK laser cooled ions we have realized a
deterministic single ion source which could operate with a huge range of
sympathetically cooled ion species, isotopes or ionic molecules. We have
deterministically extracted a predetermined number of ions on demand and have
measured a longitudinal velocity uncertainty of 6.3m/s and a spatial beam
divergence of 0.6 mrad. We show in numerical simulations that if the ions are
cooled to the motional ground state (Heisenberg limit) nanometre spatial
resolution can be achieved.Comment: 4 pages 4 figures. to be published in pr
Sensing rotations with multiplane light conversion
We report an experiment estimating the three parameters of a general
rotation. The scheme uses quantum states attaining the ultimate precision
dictated by the quantum Cram\'er-Rao bound. We realize the states
experimentally using the orbital angular momentum of light and implement the
rotations with a multiplane light conversion setup, which allows one to perform
arbitrary unitary transformations on a finite set of spatial modes. The
observed performance suggests a range of potential applications in the next
generation of rotation sensors.Comment: 8 pages, 4 figures. Comments welcome! arXiv admin note: text overlap
with arXiv:2012.0059
Optimized focusing ion optics for an ultracold deterministic single ion source targeting nm resolution
Using a segmented ion trap with mK laser-cooled ions we have realised a novel
single ion source which can deterministically deliver a wide range of ion
species, isotopes or ionic molecules [Schnitzler et al., Phys. Rev. Lett. 102,
070501 (2009)]. Experimental data is discussed in detail and compared with
numerical simulations of ion trajectories. For the novel ion source we
investigate numerically the influence of various extraction parameters on
fluctuations in velocity and position of the beam. We present specialized ion
optics and show from numerical simulations that nm resolution is achievable.
The Paul trap, which is used as a single ion source, together with the
presented ion optics, constitutes a promising candidate for a deterministic ion
implantation method for applications in solid state quantum computing or
classical nano-electronic devices.Comment: 17 pages, 13 figures (including 2 color figures), submitted to
special issue of Journal of Modern Optics - Conference Proceedings of
PQE-200
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