Magnetic Properties Of The Quasi-Two-Dimensional S=1/2 Heisenberg Antiferromagnet [Cu(Pyz)(2)(Hf2)]Pf6

We report on high-field magnetization, specific heat, and electron-spin-resonance (ESR) studies of the quasi-two-dimensional spin-1/2 Heisenberg antiferromagnet [Cu(pyz)(2)(HF2)]PF6. The frequency-field diagram of ESR modes below T-N=4.38 K is described in the frame of the mean-field theory, confirming a collinear magnetic structure with an easy-plane anisotropy. The obtained results allowed us to determine the anisotropy/exchange interaction ratio, A/J=0.003, and the upper limit for the interplane/intraplane exchange interaction ratio, J\u27/J=1/16. It is argued that despite the onset of three-dimensional long-range magnetic ordering the magnetic properties of this material (including high-magnetic-field magnetization and nonmonotonic field dependence of the Neel temperature) are strongly affected by two-dimensional spin correlations

Tunable beam shaping with a phased array acousto-optic modulator

We demonstrate the generation of Bessel beams using an acousto-optic array based on a liquid filled cavity surrounded by a cylindrical multi-element ultrasound transducer array. Conversion of a Gaussian laser mode into a Bessel beam with tunable order and position is shown. Also higher-order Bessel beams up to the fourth order are successfully generated with experimental results very closely matching simulations

Speckle-scale focusing in the diffusive regime with time reversal of variance-encoded light (TROVE)

Focusing of light in the diffusive regime inside scattering media has long been considered impossible. Recently, this limitation has been overcome with time reversal of ultrasound-encoded light (TRUE), but the resolution of this approach is fundamentally limited by the large number of optical modes within the ultrasound focus. Here, we introduce a new approach, time reversal of variance-encoded light (TROVE), which demixes these spatial modes by variance encoding to break the resolution barrier imposed by the ultrasound. By encoding individual spatial modes inside the scattering sample with unique variances, we effectively uncouple the system resolution from the size of the ultrasound focus. This enables us to demonstrate optical focusing and imaging with diffuse light at an unprecedented, speckle-scale lateral resolution of ~5 µm

Measuring Corporate Social Responsibility in tourism: Development and validation of an efficient measurement scale in the hospitality industry.

ABSTRAC: This article aims at developing an efficient measurement scale for corporate social responsibility in the tourism industry, given the contextual character that is recognized in the practice of this construct. Indicators were generated on the basis of a literature review and qualitative research. To assess the reliability and validity, first- and second-order confirmatory factor analysis were carried out. Results show a multidimensional structure of this construct—including economic, social, and environmental issues. This study contributes to the advancement of knowledge in the field of social responsibility through its practical application regarding concepts of sustainable development which have mainly been theoretical

Memory effect assisted imaging through multimode optical fibres (dataset)

Dataset to accompany the article 'Memory effect assisted imaging through multimode optical fibres'. Contains the raw data used to generate all experimental figures in the article, along with Matlab programs to open and display the data.This is the dataset used for the Li et al. (2021) article "Memory effect assisted imaging through multimode optical fibres" published in Nature Communications.National Natural Science Foundation of ChinaThe Royal SocietyEuropean Regional Development FundEuropean Research Council (ERC)Royal Academy of Engineering and the European Research Counci

Compressively sampling the optical transmission matrix of a multimode fibre (dataset)

Dataset to accompany the article 'Compressively sampling the optical transmission matrix of a multimode fibre'. Contains all of the raw data used to make the experimental figures in the article, along with Matlab programs to open the data.The article associated with this dataset is available in ORE at: http://hdl.handle.net/10871/125529This is the dataset used for the Li et al. (2021) article "Compressively sampling the optical transmission matrix of a multimode fibre" published in Light: Science and Applications.National Natural Science Foundation of ChinaNational Science Foundation (NSF)European Regional Development Fund (ERDF)European Research Council (ERC)Royal Academy of Engineering (RAE

Spin anisotropy in Cu en H2O 2SO4 A quasi two dimensional S 1 2 spatially anisotropic triangular lattice antiferromagnet

We have studied in detail the effect of the spin anisotropy on the electron paramagnetic resonance spectra and magnetic properties of Cu en H2O 2SO4, an S 1 2 spatially anisotropic triangular lattice antiferromagnet. The angular and temperature dependence of the resonance fields as well as the magnetization and magnetic susceptibility reflect the exchange and g factor anisotropy with Jz Jx,y lt; 1 and gz gx,y gt; 1, respectively. The exchange anisotropy and Dzyaloshinskii Moriya interaction are responsible for the main broadening mechanism at higher temperatures while spin diffusion effects prevail at helium temperatures. The ratio of the uniform susceptibilities calculated along the three crystal directions suggests an easy axis anisotropy with the a axis as the magnetic easy axis. Its impact on the physical properties of the title compound is discusse

Neutron and EPR Study of Cu tn Cl 2 a Two Dimensional Spatially Anisotropic Triangular Lattice Antiferromagnet

We have studied the temperature dependence of the lattice parameters and the influence of spin anisotropy on the electron paramagnetic spectra of $Cu(tn)Cl_2$, an S=1/2 quasi-two-dimensional spatially-anisotropic triangular-lattice Heisenberg antiferromagnet. The variation of the resonance fields with temperature reflects the presence of an easy-plane exchange anisotropy with $J_{z}$/$J_{x,y}$1

Fibre based cellular transfection

Optically assisted transfection is emerging as a powerful and versatile method for the delivery of foreign therapeutic agents to cells at will. In particular the use of ultrashort pulse lasers has proved an important route to transiently permeating the cell membrane through a multiphoton process. Though optical transfection has been gaining wider usage to date, all incarnations of this technique have employed free space light beams. In this paper we demonstrate the first system to use fibre delivery for the optical transfection of cells. We engineer a standard optical fibre to generate an axicon tip with an enhanced intensity of the remote output field that delivers ultrashort (~ 800 fs) pulses without requiring the fibre to be placed in very close proximity to the cell sample. A theoretical model is also developed in order to predict the light propagation from axicon tipped and bare fibres, in both air and water environments. The model proves to be in good agreement with the experimental findings and can be used to establish the optimum fibre parameters for successful cellular transfection. We readily obtain efficiencies of up to 57 % which are comparable with free space transfection. This advance paves the way for optical transfection of tissue samples and endoscopic embodiments of this technique