269 research outputs found
Deeply-trapped molecules in self-nanostructured gas-phase material
Since the advent of atom laser-cooling, trapping or cooling natural molecules
has been a long standing and challenging goal. Here, we demonstrate a method
for laser-trapping molecules that is radically novel in its configuration, in
its underlined physical dynamics and in its outcomes. It is based on
self-optically spatially-nanostructured high pressure molecular hydrogen
confined in hollow-core photonic-crystal-fibre. An accelerating
molecular-lattice is formed by a periodic potential associated with Raman
saturation except for a 1-dimentional array of nanometer wide and
strongly-localizing sections. In these sections, molecules with a speed of as
large as 1800 m/s are trapped, and stimulated Raman scattering in the
Lamb-Dicke regime occurs to generate high power forward and backward-Stokes
continuous-wave laser with sideband-resolved sub-Doppler emission spectrum. The
spectrum exhibits a central line with a sub-recoil linewidth of as low as 14
kHz, more than 5 orders-of-magnitude narrower than in conventional Raman
scattering, and sidebands comprising Mollow triplet, molecular
motional-sidebands and four-wave-mixing.Comment: 28 pages 1-12 for main manuscript 13-28 for Methodes and appendices 4
figures for Main manuscript 12 figures for the Methods par
A strong-field driver in the single-cycle regime based on self-compression in a kagome fibre
Over the past decade intense laser fields with a single-cycle duration and even shorter, subcycle multicolour field transients have been generated and applied to drive attosecond phenomena in strong-field physics. Because of their extensive bandwidth, single-cycle fields cannot be emitted or amplified by laser sources directly and, as a rule, are produced by external pulse compression—a combination of nonlinear optical spectral broadening followed up by dispersion compensation. Here we demonstrate a simple robust driver for high-field applications based on this Kagome fibre approach that ensures pulse self-compression down to the ultimate single-cycle limit and provides phase-controlled pulses with up to a 100 μJ energy level, depending on the filling gas, pressure and the waveguide length
Tailoring the nonlinear response of hollow-core photonic bandgap fibres
International audienceWe have fabricated 7-cell and 3-cell core hollow-core photonic bandgap fibres with core sizes ranging from 16.7 mu m to 6.5 mu m. A numerical study of the nonlinear coefficient of fibres with different core sizes is carried out. We show that the nonlinearity is more effectively increased by a 3-cell core design than by reducing the size of a seven-cell core
Genetic Decomposition of the Heritable Component of Reported Childhood Maltreatment
BACKGROUND:
Decades of research have shown that environmental exposures, including self-reports of trauma, are partly heritable. Heritable characteristics may influence exposure to and interpretations of environmental factors. Identifying heritable factors associated with self-reported trauma could improve our understanding of vulnerability to exposure and the interpretation of life events.
METHODS:
We used genome-wide association study summary statistics of childhood maltreatment, defined as reporting of abuse (emotional, sexual, and physical) and neglect (emotional and physical) (N = 185,414 participants). We calculated genetic correlations (rg) between reported childhood maltreatment and 576 traits to identify phenotypes that might explain the heritability of reported childhood maltreatment, retaining those with |rg| > 0.25. We specified multiple regression models using genomic structural equation modeling to detect residual genetic variance in childhood maltreatment after accounting for genetically correlated traits.
RESULTS:
In 2 separate models, the shared genetic component of 12 health and behavioral traits and 7 psychiatric disorders accounted for 59% and 56% of heritability due to common genetic variants (single nucleotide polymorphism–based heritability [h2SNP]) of childhood maltreatment, respectively. Genetic influences on h2SNP of childhood maltreatment were generally accounted for by a shared genetic component across traits. The exceptions to this were general risk tolerance, subjective well-being, posttraumatic stress disorder, and autism spectrum disorder, identified as independent contributors to h2SNP of childhood maltreatment. These 4 traits alone were sufficient to explain 58% of h2SNP of childhood maltreatment.
CONCLUSIONS:
We identified putative traits that reflect h2SNP of childhood maltreatment. Elucidating the mechanisms underlying these associations may improve trauma prevention and posttraumatic intervention strategies
Compression of picosecond optical pulses in tapered hollow-core photonic bandgap fiber
International audienceWe demonstrate nonlinear compression of 2.5ps and 1.2ps laser pulses at 800nm wavelength using a 35m tapered hollow-core photonic bandgap fiber with continuously decreasing dispersio
Solitons in hollow core photonic crystal fiber:Engineering nonlinearity and compressing pulses
International audienc
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