Publications associées à Design and fabrication of a novel centimeter scale three dimensional silicon tip, tilt and piston mirror mechanism

Infrared-active phonons in one-dimensional materials and their spectroscopic signatures

Nicola Marzari, Thibault Daniel Pierre Sohier, Norma Rivano

Dimensionality provides a clear fingerprint on the dispersion of infrared-active, polar-optical phonons. For these phonons, the local dipoles parametrized by the Born effective charges drive the LO-TO splitting of bulk materials; this splitting actually br ...

Nature Portfolio2023

Nonlinear dynamics and Kerr frequency comb formation in lattices of coupled microresonators

Tobias Kippenberg, Kenichi Komagata, Alexey Tikan, Aleksandr Tusnin

Recently, substantial progress has been made in the understanding of microresonators frequency combs based on dissipative Kerr solitons (DKSs). However, most of the studies have focused on the single-resonator level. Coupled resonator systems can open new ...

Nature Portfolio2023

Well-posedness Issues For the Half-Wave Maps Equation With Hyperbolic And Spherical Targets

Yang Liu

This thesis is a study of the global well-posedness of the Cauchy problems for half-wave maps from the Minkowski space of dimension n+1 to the 2-dimensional sphere and the hyperbolic plane. The work is mainly based on the results from Krieger-Sire 17' in ...

EPFL2023

High density lithium niobate photonic integrated circuits

Rui Ning Wang, Tobias Kippenberg, Mikhail Churaev, Anat Siddharth, Zelin Tan, Nikolai Kuznetsov, Zihan Li, Junyin Zhang

Photonic integrated circuits have the potential to pervade into multiple applications traditionally limited to bulk optics. Of particular interest for new applications are ferroelectrics such as Lithium Niobate, which exhibit a large Pockels effect, but ar ...

Nature Portfolio2023

Long-range electrostatic contribution to electron-phonon couplings and mobilities of two-dimensional and bulk materials

Massimiliano Stengel, Nicola Marzari, Marco Gibertini, Samuel Poncé

Charge transport plays a crucial role in manifold potential applications of two-dimensional materials, in-cluding field-effect transistors, solar cells, and transparent conductors. At most operating temperatures, charge transport is hindered by scattering ...

AMER PHYSICAL SOC2023

Inference and Computation for Sparsely Sampled Random Surfaces

Victor Panaretos, Tomas Rubin, Tomas Masák

Nonparametric inference for functional data over two-dimensional domains entails additional computational and statistical challenges, compared to the one-dimensional case. Separability of the covariance is commonly assumed to address these issues in the de ...

TAYLOR & FRANCIS INC2022

Reduced representations of complexes, signals, and multifiltrations

Celia Camille Hacker

The field of computational topology has developed many powerful tools to describe the shape of data, offering an alternative point of view from classical statistics. This results in a variety of complex structures that are not always directly amenable for ...

EPFL2022

Low-Loss Anisotropic Image Polaritons in van der Waals Crystal alpha-MoO3

Sergejs Boroviks

Orthorhombic molybdenum trioxide (alpha-MoO3), a newly discovered polaritonic van der Waals crystal, is attracting significant attention due to its strongly anisotropic mid-infrared phonon-polaritons. At the same time, coupling of polariton with its mirror ...

WILEY-V C H VERLAG GMBH2022

Investigation of femtosecond laser-enabled 3D micro-infiltration processes

Enrico Casamenti

In the last decades, the femtosecond laser micromachining of glass has attracted a lot of attention due to its three-dimensional manufacturing ability and flexibility both in terms of compatible substrates and modification types. Yet, to fully unravel its ...

EPFL2022

Reduced basis methods for numerical room acoustic simulations with parametrized boundaries

Jan Sickmann Hesthaven, Hermes Sampedro Llopis

The use of model-based numerical simulations of wave propagation in rooms for engineering applications requires that acoustic conditions for multiple parameters are evaluated iteratively, which is computationally expensive. We present a reduced basis metho ...

ACOUSTICAL SOC AMER AMER INST PHYSICS2022

Demonstrating and Unraveling a Controlled Nanometer-Scale Expansion of the Vacancy Defects in Graphene by CO2

Kumar Varoon Agrawal, Luis Francisco Villalobos Vazquez de la Parra, Kuang-Jung Hsu

A controlled manipulation of graphene edges and vacancies is desired for molecular separation, sensing and electronics applications. Unfortunately, available etching methods always lead to vacancy nucleation making it challenging to control etching. Herein ...

Wiley-VCH Verlag GmbH2022

Smart Slit Assembly Employing Continuously Tunable MEMS Shutter

Benedikt Guldimann, Niels Quack, Gergely Huszka, Hamed Sattari, Anton Lagosh

We present the concept and detailed design of a Smart Slit Assembly for next generation spectrometers, and we experimentally demonstrate operation of an individual 221 mu m x 111 mu m smart slit channel employing a MEMS actuated shutter to continuously mod ...

SPIE-INT SOC OPTICAL ENGINEERING2021

Free Boundary Regularity for Almost Every Solution to the Signorini Problem

Xavier Fernandez-Real Girona

We investigate the regularity of the free boundary for the Signorini problem in Rn+1. It is known that regular points are (n−1)-dimensional and C∞. However, even for C∞ obstacles φ, the set of non-regular (or degenerate) points could be very large—e.g. wit ...

2021

Systematic design of millisecond gasification reactor for the incorporation of gas-sieving nanopores in single-layer graphene

Kumar Varoon Agrawal, Shiqi Huang, Luis Francisco Villalobos Vazquez de la Parra, Shaoxian Li, Kuang-Jung Hsu

Etching an ensemble of vacancy defects (nanopores) in single-layer graphene (SLG) to obtain a high density of nanopores with an effective size that enables high-performance gas sieving is challenging. This is because nanopore nucleation and expansion are u ...

2021

Method and system for generating a three-dimensional model based on spherical photogrammetry

Pierre-André Mudry, Frédéric Kaplan, Nils Hamel, Albane Bénédicte Descombes

A computer-implemented method is proposed for creating a three-dimensional model of the environment. The method comprises the steps of planning (105) a trajectory for a moving system carrying an omnidirectional camera comprising a first image sensor facing ...

2021

Mems Shutter Based Variable Optical Attenuator Integrated With Large Core Multimode Rectangular Waveguides

Benedikt Guldimann, Niels Quack, Gergely Huszka, Hamed Sattari, Anton Lagosh

We present the concept and design, and we report on the experimental performance of a broadband Variable Optical Attenuator (VOA) for integration with large-core rectangular multimode waveguides. Operation of an individual 221 mu m x 111 mu m optical waveg ...

IEEE2021

Contact process under renewals II

Thomas Mountford

We continue the study of renewal contact processes initiated in a companion paper, where we showed that if the tail of the interarrival distribution mu is heavier than t(-alpha) for some alpha < 1 (plus auxiliary regularity conditions) then the critical va ...

ELSEVIER2020

Single crystal diamond gain mirrors for high performance vertical external cavity surface emitting lasers

Niels Quack, Grigore Suruceanu, Alexandru Mereuta, Andrei Caliman, Pascal Gallo, Gergely Huszka, Mehdi Naamoun

We report on the design, fabrication and optical performance of gain mirrors in single crystal diamond substrates for vertical external cavity surface emitting lasers (VECSELs). VECSELs have gained attention recently due to their potential for high emissio ...

2020

A p-weighted limiter for the discontinuous Galerkin method on one-dimensional and two-dimensional triangular grids

Qian Wang, Qian Wang

This paper presents an accuracy-preserving p-weighted limiter for discontinuous Galerkin methods on one-dimensional and two-dimensional triangular grids. The p-weighted limiter is the extension of the second-order WENO limiter by Li et al. [W. Li, J. Pan a ...

2020

Real- and Q-space travelling: multi-dimensional distribution maps of crystal-lattice strain (epsilon(044)) and tilt of suspended monolithic silicon nanowire structures

Yusuf Leblebici, Alex Dommann, Zuhal Tasdemir, Antonia Neels, Simone Dolabella

Silicon nanowire-based sensors find many applications in micro- and nano-electromechanical systems, thanks to their unique characteristics of flexibility and strength that emerge at the nanoscale. This work is the first study of this class of micro- and na ...

INT UNION CRYSTALLOGRAPHY2020