Publications associées à Low-temperature cross polarization in view of enhancing dissolution Dynamic Nuclear Polarization in NMR

Dual-shot approach for polarization retrieval through a scattering medium

A dual-shot technique based on the field basis addition of two statistically independent speckle patterns is developed to recover an input polarization through a scattering layer. It is proposed theoretically, and demonstrated both numerically and experime ...

Iop Publishing Ltd2024

Circularly polarized planar antenna with axially symmetric beamwidth reconfigurability

Anja Skrivervik, Ismael Vico Triviño, Hannes Bartle

This contribution presents the design of a compact circularly polarized antenna featuring beamwidth reconfiguration in both the horizontal and vertical planes. The observed radiation patterns in each of the reconfigurable states present axial symmetry and ...

IEEE2023

Ultralong 100 ns spin relaxation time in graphite at room temperature

László Forró, Bálint Náfrádi, Péter Szirmai, Bence Gábor Márkus

Graphite has been intensively studied, yet its electron spins dynamics remains an unresolved problem even 70 years after the first experiments. The central quantities, the longitudinal (T-1) and transverse (T-2) relaxation times were postulated to be equal ...

Nature Portfolio2023

Magnetic structure of the two-dimensional XY antiferromagnet Sr2CoSi2O7 studied using single-crystal neutron diffraction

Bálint Náfrádi

We report a combined polarized and unpolarized neutron diffraction study on a multiferroic Sr2CoSi2O7 (SCSO) single crystal below and above the antiferromagnetic ordering temperature TN = 6.5 K. Unpolarized neutron diffraction measurements at 15 K confirm ...

AMER PHYSICAL SOC2023

Performance and reproducibility of C-13 and N-15 hyperpolarization using a cryogen-free DNP polarizer

Hikari Ananda Infinity Yoshihara, Arianna Ferrari

The setup, operational procedures and performance of a cryogen-free device for producing hyperpolarized contrast agents using dissolution dynamic nuclear polarization (dDNP) in a preclinical imaging center is described. The polarization was optimized using ...

Nature Portfolio2022

Enhancing the beamwidth of low profile single-fed microstrip antennas using parasitic elements

Anja Skrivervik, Ismael Vico Triviño

In this paper we present a technique to broaden the beamwidth of conventional patch microstrip antennas by using parasitic elements. This technique allows to keep the main advantages of microstrip antennas while increasing their beamwidth. We provide guide ...

IEEE2022

Direct measurement of the triple spin flip rate in dynamic nuclear polarization

Andrea Capozzi

A previous study of the effect of Gadolinium doping on the dynamic polarization (DNP) of C-13 using trityls showed that the rate at which the polarization builds up is almost independent of the Gadolinium concentration, while the electron spin-lattice rela ...

Academic Press Inc - Elsevier Science2021

Smooth GaN membranes by polarization-assisted electrochemical etching

Jean-François Carlin, Nicolas Grandjean, Joachim Armand Simonne Ciers

III-nitride membranes offer promising perspectives and improved device designs in photonics, electronics, and optomechanics. However, the removal of the growth substrate often leads to a rough membrane surface, which increases scattering losses in optical ...

AMER INST PHYSICS2021

Methods to Enhance Nuclear Magnetic Resonance Sensitivity at High Magnetic Field

Claudia Christina Zanella

MR is a well-established technique routinely used in preclinical and clinical studies. This thesis focussed on the improvement of sensitivity of different methods in MR. Hyperpolarized 129Xe gas is used for studying pulmonary disease or cerebral perfusion ...

EPFL2021

Extreme polarization-dependent supercontinuum generation in an uncladded silicon nitride waveguide

Camille Sophie Brès, Eirini Tagkoudi, Caroline Gaëlle Amiot

We experimentally demonstrate the generation of a short-wave infrared supercontinuum in an uncladded silicon nitride (Si3N4) waveguide with extreme polarization sensitivity at the pumping wavelength of 2.1 µm. The air-clad waveguide is specifically designe ...

2021

Quantification of magic angle spinning dynamic nuclear polarization NMR spectra

David Lyndon Emsley, Pierrick Berruyer, Andrea Bertarello

Dynamic nuclear polarization (DNP) allows to dramatically enhance the sensitivity of magic angle spinning nuclear magnetic resonance (MAS NMR). DNP experiments usually rely on the detection of low-γ nuclei hyperpolarized from 1H with the use of cross polar ...

Academic Press Inc - Elsevier Science2021

Hyperpolarization of inorganic solids

Snaedis Björgvinsdóttir

Solid-state NMR can provide information about the atomic level structure and dynamics of materials. It directly probes symmetry and structure at nuclear sites, and is especially useful for investigation of disordered or amorphous solids that lack long rang ...

EPFL2020

Circularly Polarized Axially Corrugated Feed Horn for CubeSat Reflectarray Applications

Anja Skrivervik, Miroslav Veljovic

Retlectarray (RA) and transmitarray (TA) antennas that use the element-rotation technique require the radiation from the feeding antenna to be circularly polarized (CP). A CP axially corrugated horn antenna is developed as a feeding element for CubeSat RA ...

IEEE2020

Interplay of anomalous strain relaxation and minimization of polarization changes at nitride semiconductor heterointerfaces

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Yi Wang

We present a methodology to quantify polarization and electron affinity changes at interfaces by combining scanning tunneling spectroscopy, off-axis electron holography in transmission electron microscopy (TEM), and self-consistent calculations of the elec ...

AMER PHYSICAL SOC2020

Ultra-Broadband and Omnidirectional Perfect Absorber Based on Copper Nanowire/Carbon Nanotube Hierarchical Structure

Giulia Tagliabue, Fateme Kiani Shahvandi, Theodoros Tsoulos

Zero reflection and complete light absorption are required in a wide range of applications ranging from sensing devices to solar heaters and photoelectrodes. However, simultaneously satisfying the requirements of the broadband spectrum, omnidirectionality, ...

AMER CHEMICAL SOC2020

Spin-dependent charge transfer at chiral electrodes probed by magnetic resonance

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

Chirality-induced spin selectivity is evidenced by exciting the spin resonance of radicals in an electrochemical cell where the working electrode is covered with a chiral self-assembled monolayer. Because the electron transfer to and from the paramagnetic ...

ROYAL SOC CHEMISTRY2020

Measuring the Intra-Atomic Exchange Energy in Rare-Earth Adatoms

Harald Brune, François Patthey, Stefano Rusponi, Marina Pivetta

We present the first experimental determination of the intra-atomic exchange energy between the inner 4f and the outer 6s5d shells in rare-earth elements. Inelastic electron tunneling spectroscopy on individual rare-earth atoms adsorbed on metal-supported ...

American Physical Society2020

Chiral Spin-Wave Velocities Induced by All-Garnet Interfacial Dzyaloshinskii-Moriya Interaction in Ultrathin Yttrium Iron Garnet Films

Haiming Yu, Song Liu, Peng Gao, Dirk Grundler, Ping Che, Yuehui Li, Sa Tu, Jilei Chen, Jianyu Zhang, Tao Liu

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In ...

2020

Matrix Fourier optics enables a compact full-Stokes polarization camera

Gabriele D'Aversa

Recent developments have enabled the practical realization of optical elements in which the polarization of light may vary spatially. We present an extension of Fourier optics-matrix Fourier optics-for understanding these devices and apply it to the design ...

American Association for the Advancement of Science2019

Terahertz-optical properties of a bismuth ferrite single crystal

Jean-Philippe Ansermet, Henrik Moodysson Rønnow, Marcin Bialek

Transmission through a (100)-oriented single crystal of bismuth ferrite (BiFeO3) was studied at frequencies of 0.485-0.765 THz with a continuous-wave source and in the temperature range of 30-350 K as a function of polarization angle. The fine splitting of ...

2019