Search results for "Polarization"
showing 10 items of 1884 documents
Measurement of high order Kerr refractive index of major air components
2009
International audience; We measure the instantaneous electronic nonlinear refractive index of N2 , O2 , and Ar at room temperature for a 90 fs and 800 nm laser pulse. Measurements are calibrated by post-pulse molecular alignment through a polarization technique. At low intensity, quadratic coefficients n2 are determined. At higher intensities, a strong negative contribution with a higher nonlinearity appears, which leads to an overall negative nonlinear Kerr refractive index in air above 26 TW/cm2 .
Theory of spontaneous polarization and birefringence in the tetragonal phase of KNbO3
1995
Abstract The microscopic mechanism of optical anisotropy in the tetragonal phase of KNbO3 is discussed taking account of the dipole-dipole effect due to the ionic and electronic polarizations of the crystal and the spontaneous Kerr effect. The last effect is a cause of the strong local field acting on the constituent ions. For the spontaneous polarization we use only the first effect. It is found that the birefringence and the spontaneous polarization are in good agreement with the experimental data.
Measurement of high order Kerr refractive index of major air components: erratum
2010
A clarification is missing concerning the high order Kerr non-linearities deduced from our experimental data published in [Opt. Express 17, 13429-13434 (2009)]. Here, we rectify this omission by making explicit the distinction between cross-Kerr and Kerr effects, and by extrapolating the value of the nonlinear refractive index for the last effect. Since the occurrence of sign inversion in the Kerr effect is not affected, the overall report in [Opt. Express 17, 13429-13434] remains valid.
Predicting the structure and vibrational frequencies of ethylene using harmonic and anharmonic approaches at the Kohn–Sham complete basis set limit
2016
In this work, regular convergence patterns of the structural, harmonic, and VPT2-calculated anharmonic vibrational parameters of ethylene towards the Kohn–Sham complete basis set (KS CBS) limit are demonstrated for the first time. The performance of the VPT2 scheme implemented using density functional theory (DFT-BLYP and DFT-B3LYP) in combination with two Pople basis sets (6-311++G** and 6-311++G(3df,2pd)), the polarization-consistent basis sets pc-n, aug-pc-n, and pcseg-n (n = 0, 1, 2, 3, 4), and the correlation-consistent basis sets cc-pVXZ and aug-cc-pVXZ (X = D, T, Q, 5, 6) was tested. The BLYP-calculated harmonic frequencies were found to be markedly closer than the B3LYP-calculated h…
Measurement of the mixing-induced and CP-violating parameters of Bs -> phi gamma decays at LHCb
2018
En esta tesis se presenta la primera medida de los observables de violación de CP e inducidos por mezcla de la desintegración Bs -> phi gamma (los observables A, S y C), que aparecen en la fracción de desintegración en función del tiempo. Se han utilizado los datos tomados por el experimento LHCb durante los años 2011 y 2012, representando una luminosidad integrada de 3 fb-1 en total. El Modelo Estándar de física de partículas describe las propiedades de todas las partículas elementales y de las interacciones fuerte, débil y electromagnética. A pesar de su gran éxito predictivo, resulta necesaria una extensión del mismo puesto que no explica determinados fenómenos que han sido observados en…
Search for radiative b-baryon decays and study of their anomalous photon polarization at LHCb
2022
En esta tesis se presenta el estudio de dos desintegraciones radiativas de bariones que contienen un quark bottom: Lambda_b -> Lambda gamma and Xi_b^- -> Xi^- gamma. En primer lugar, se ha realizado una búsqueda de dichas desintegraciones usando datos tomados por el experimento LHCb para medir sus fracciones de desintegración. En segundo lugar, se usan los candidatos señal para medir la polarización del fotón a haciendo uso del formalismo de helicidad. Esta tesis presenta la primera medida de la polarización del fotón usando la desintegración radiativa b-bariónica Lambda_b -> Lambda gamma, y el primer estudio de la desintegración Xi_b^- -> Xi^- gamma. El marco teórico actual de la física de…
Imbalanced Job Polarization and Skills Mismatch in Europe
2016
Abstract This paper considers the education of the labour force based on an analysis of trends in and the relationships between job polarization and skills mismatch. Both job polarization and skills mismatch have become topics of increasing interest, but relationships between the two have been relatively neglected in the literature. We argue that the relationship between polarization and skills mismatch is an empirical matter, which we analyse at both the macroeconomic and microeconomic level in European countries. A novel job polarization index (JPI) is proposed to measure imbalanced job polarization. It takes into account not only the change in the share of medium-level jobs, as is typica…
Interface-Assisted Sign Inversion of Magnetoresistance in Spin Valves Based on Novel Lanthanide Quinoline Molecules
2018
Molecules are proposed to be an efficient medium to host spin-polarized carriers, due to their weak spin relaxation mechanisms. While relatively long spin lifetimes are measured in molecular devices, the most promising route toward device functionalization is to use the chemical versatility of molecules to achieve a deterministic control and manipulation of the electron spin. Here, by combining magnetotransport experiments with element-specific X-ray absorption spectroscopy, this study shows the ability of molecules to modify spin-dependent properties at the interface level via metal–molecule hybridization pathways. In particular, it is described how the formation of hybrid states determine…
Comments on 'formation and characterization of nanotubes of La(OH) 3 obtained using porous alumina membranes'
2010
New experimental evidence concerning the formation of La(OH)3 nanowires on anodic alumina membranes by cathodic polarization in 0.05 M lanthanum nitrate solution is provided to further support the conclusions previously reached in our work (Bocchetta et al 2007 Electrochem. Commun. 9 683-8) and recently criticized by González-Rovira et al (Nanotechnology 2008 19 495305). Some unconvincing aspects of the paper of González-Rovira et al, according to which the same electrochemical process should lead to the formation of hydroxycarbonate nanotubes, are also discussed.
Probing Lorentz invariance and other fundamental symmetries in3He/129Xe clock-comparison experiments
2011
We discuss the design and performance of a very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized 3He or 129Xe samples with a SQUID as magnetic flux detector. Characteristic spin precession times T*2 of up to 60 h were measured in low magnetic fields (about 1μT) and in the regime of motional narrowing. With the detection of the free precession of co-located 3He/129Xe nuclear spins (clock comparison), the device can be used as ultra-sensitive probe for non-magnetic spin interactions, since the magnetic dipole interaction (Zeeman-term) drops out in the weighted frequency difference, i.e., Δω = ωHe− γHe/γXe·ωXe. We report on searches …