Publications associées à Optique cristalline

Wandering principal optical axes in van der Waals triclinic materials

Nature is abundant in material platforms with anisotropic permittivities arising from symmetry reduction that feature a variety of extraordinary optical effects. Principal optical axes are essential characteristics for these effects that define light-matte ...

Nature Portfolio2024

Exploring Novel Modalities for Optical Diffraction Tomography

Amirhossein Saba Shirvan

In the past decade, optical diffraction tomography has gained a lot of attention for its ability to create label-free three-dimensional (3D) images of the refractive index distribution of biological samples using scattered fields measured through holograph ...

EPFL2023

Long-distance distributed pressure sensing based on frequency-scanned phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Zhisheng Yang, Li Zhang

In this paper, a long-distance distributed pressure sensing system based on a special fiber and using frequency-scanned phase-sensitive optical time-domain reflectometry is proposed. The fiber shows high pressure sensitivity (159 MHz/bar) and low loss (3 d ...

2021

Sensing of Surface and Bulk Refractive Index Using Magnetophotonic Crystal with Hybrid Magneto-Optical Response

Serguei Sekatski

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical response that allows for the simultaneous measurements of the surface and bulk refractive index of the analyzed substance. The approach is based on two different spectral f ...

2021

Radial Spin Texture of the Weyl Fermions in Chiral Tellurium

Majed Chergui, Henrik Moodysson Rønnow, Marco Grioni, Oleg Yazyev, Luc Testa, Daniel Gosalbez Martinez, Michele Puppin, Philippe Bugnon, Luca Moreschini, Alberto Crepaldi, Mauro Fanciulli, Gianmarco Gatti, Simon Karl Moser, Edoardo Martino, Silvan Dino Marcos Roth, Serhii Polishchuk

Trigonal tellurium, a small-gap semiconductor with pronounced magneto-electric and magneto-optical responses, is among the simplest realizations of a chiral crystal. We have studied by spin- and angle-resolved photoelectron spectroscopy its unconventional ...

AMER PHYSICAL SOC2020

Particle suitable for the manufacture of an implantable soft tissue engineering material

Philippe Renaud, Thomas Michael Braschler, Amélie Barbara Hildegarde Béduer

The particle (1) is suitable for the manufacture of an implantable soft tissue engineering material and comprises: a three-dimensionally warped and branched sheet (2) where (i) the three-dimensionally warped and branched sheet (2) is made from a biocompati ...

2019

Parallel integro-differential equation solving via multi-channel reciprocal bianisotropic metasurface augmented by normal susceptibilities

Karim Achouri, Ali Momeni

Analog optical signal processing has dramatically transcended the speed and energy limitations accompanied with its digital microelectronic counterparts. Motivated by recent metasurface?s evolution, the angular scattering diversity of a reciprocal passive ...

2019

Generalized Optical Signal Processing Based on Multioperator Metasurfaces Synthesized by Susceptibility Tensors

Karim Achouri, Ali Momeni

This paper theoretically proposes a multichannel nonlocal metasurface computer characterized by generalized sheet transition conditions (GSTCs) and surface susceptibility tensors. The study explores polarization- and angle-multiplexed metasurfaces enabling ...

American Physical Society (APS)2019

Using Gaussian process regression to simulate the vibrational Raman spectra of molecular crystals

Michele Ceriotti, Andrea Grisafi, Mariana Rossi Carvalho

Vibrational properties of molecular crystals are constantly used as structural fingerprints, in order to identify both the chemical nature and the structural arrangement of molecules. The simulation of these properties is typically very costly, especially ...

2019

Observation of Second Harmonic and Sum Frequency in an Optically Poled Si3N4 Waveguide

Tobias Kippenberg, Camille Sophie Brès, Davide Grassani, Martin Hubert Peter Pfeiffer, Adrien Billat

Enhanced second order nonlinear processes in a Si3N4 waveguide following optically induced χ(2) is demonstrated, enabling the detection of a frequency doubled pulsed train and SFG with >-37 dB conversion efficiency for 18 W pump peak power. ...

2018

Local Structural Heterogeneity and Electromechanical Responses of Ferroelectrics: Learning from Relaxor Ferroelectrics

Dragan Damjanovic

Long-range ordering of dipoles is a key microscopic signature of ferroelectrics. These ordered dipoles form ferroelectric domains, which can be reoriented by electric fields. Relaxor ferroelectrics are a type of ferroelectric where the longrange ordering o ...

2018

Stereodynamics of Ne(3P2) reacting with Ar, Kr, Xe, and N2

Andreas Osterwalder, Junwen Zou, Sean Dennis Steven Gordon, Silvia Tanteri

Stereodynamics experiments of Ne(3P2) reacting with Ar, Kr, Xe, and N2 leading to Penning and associative ionization have been performed in a crossed molecular beam apparatus. A curved magnetic hexapole was used to state-select and polarize Ne(3P2) atoms w ...

2018

Complex Refractive Indices of Cesium–Formamidinium-Based Mixed-Halide Perovskites with Optical Band Gaps from 1.5 to 1.8 eV

Christophe Ballif, Jérémie Werner, Quentin Thomas Jeangros, Matthias Wolfgang Bräuninger, Gabriel Christmann, Florent Sahli, Arnaud Walter, Sylvain Nicolay, Björn Niesen, Gizem Nogay, Philipp Friedrich Hermann Löper, Chien-Jen Yang, Peter Joseph Fiala

Cesium-formamidinium-based mixed-halide perovskite materials with optical band gaps ranging from 1.5 to 1.8 eV are investigated by variable-angle spectroscopic ellipsometry. The determined complex refractive indices are shown to depend on the fabrication p ...

2018

Study of the Angular Spectrum of a Bianisotropic Refractive Metasurface at a Dielectric Interface

Karim Achouri, Christophe Caloz

We present an initial study of the angular spectrum of a bianisotropic refractive metasurface at an interface between two dielectric media. In this study, we report on the existence of three distinct angular regions: a) a rotated transmission cone, b) a mo ...

IEEE2018

The Role of Anisotropy on the Volumetric Behaviour of Opalinus Clay upon Suction Change

Lyesse Laloui, Alessio Ferrari, Eleonora Crisci, Alberto Minardi

An experimental investigation to analyse the anisotropic volumetric response of shaly and sandy facies of Opalinus Clay upon suction variations is presented. Obtained results demonstrate the different behaviour of the tested facies to a wetting-drying cycl ...

Springer2017

Skyrmion dynamics under uniaxial anisotropy

Dirk Grundler

Broadband microwave spectroscopy has been performed on single-crystalline GaV4S8, which exhibits a complex magnetic phase diagram including cycloidal and Neel-type skyrmion lattice phases below 13 K. At small magnetic fields two collective modes with large ...

Amer Physical Soc2016

Internal optical forces in plasmonic nanostructures

Olivier Martin

We present a computational study of the internal optical forces arising in plasmonic gap antennas, dolmen structures and split rings. We find that very strong internal forces perpendicular to the propagation direction appear in these systems. These interna ...

Optical Society of America2015

Distributed phase birefringence measurements based on polarization correlation in phase-sensitive optical time-domain reflectometers

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

In this paper a technique to measure the distributed birefringence profile along optical fibers is proposed and experimentally validated. The method is based on the spectral correlation between two sets of orthogonally-polarized measurements acquired using ...

Optical Society of America2015

Brillouin dynamic gratings in optical fibres for distributed sensing and advanced optical signal processing

Andrey Denisov

This thesis presents results of a research on applications of Brillouin dynamic gratings - distributed reflectors that can be dynamically created in an optical fibre by two optical waves. A basic theory of stimulated Brillouin scattering (SBS) is introduce ...

EPFL2015

In-situ structural investigations of ferroelasticity in soft and hard rhombohedral and tetragonal PZT

Dragan Damjanovic

Despite the technological importance of hard and soft PZT, Pb(Zr,Ti)O3, ceramics, the mechanisms of ferroelectric hardening and softening remain widely discussed in the literature. The hardening and softening phenomena have traditionally been investigated ...

American Institute of Physics2015