Publications associées à Harmonique (musique)

Shedding light on the MRI-driven dynamo in a stratified shearing box

We study the magneto-rotational instability (MRI) dynamo in a geometrically thin disc (H/R < 1) using stratified zero net (vertical) flux shearing box simulations. We find that mean fields and electromotive forces (EMFs) oscillate with a primary frequency ...

2024

Observation of non-reciprocal harmonic conversion in real sounds

Romain Christophe Rémy Fleury, Hervé Lissek, Xinxin Guo

Reciprocity guarantees that in most media, sound transmission is symmetric between two points of space when the location of the source and receiver are interchanged. This fundamental law can be broken in non-linear media, often at the cost of detrimental i ...

2023

Tunable photo-induced second-harmonic generation in a mode-engineered silicon nitride microresonator

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Boris Zabelich, Edgars Nitiss

All-optical poling enables reconfigurable and efficient quasi-phase-matching for second-order parametric frequency conversion in silicon nitride integrated photonics. Here, we report broadly tunable milliwatt-level second-harmonic generation in a small fre ...

2023

Nonlinear Frequency Conversion in III-Nitride Doubly Resonant Photonic Crystal Cavities

Jun Wang

Nonlinear frequency conversion processes, such as second-harmonic generation (SHG) and spontaneous parametric down-conversion (SPDC), are essential in many applications, including the generation of entangled photons. It's desirable to enhance these process ...

EPFL2023

A chip-scale second-harmonic source via self-injection-locked all-optical poling

Tobias Kippenberg, Camille Sophie Brès, Junqiu Liu, Edgars Nitiss, Marco Clementi

Second-harmonic generation allows for coherently bridging distant regions of the optical spectrum, with applications ranging from laser technology to self-referencing of frequency combs. However, accessing the nonlinear response of a medium typically requi ...

2023

Self-sustained dynamics and forced resonant oscillations in flows: cross-junction jets and sloshing liquids

Alessandro Bongarzone

In engineering, oscillatory instabilities and resonances are often considered undesirable flow features and measures are taken to avoid them. This may include avoiding certain parametric regions or implementing control and mitigation strategies. However, t ...

EPFL2023

Data-driven 1D wave propagation for site response analysis

Jean-François Molinari, Antonio Joaquin Garcia Suarez, Sacha Zenon Wattel

Prediction of ground motion triggered by earthquakes is a prime concern for both the seismology community and geotechnical earthquake engineering one. The subfield occupied with such a problem is termed site response analysis (SRA), its one-dimensional fla ...

WILEY2023

Harmonic decomposition of the trace of 1D transfer matrices in layered media

Antonio Joaquin Garcia Suarez

The Transfer Matrix formalism is ubiquitous when it comes to study wave propagation in various stratified media, applications ranging from Seismology to Quantum Mechanics. A relation between variables at two points in two different layers can be establishe ...

2022

A Structured Dictionary Perspective on Implicit Neural Representations

Pascal Frossard, Guillermo Ortiz Jimenez, Beril Besbinar, Gizem Yüce

Implicit neural representations (INRs) have recently emerged as a promising alternative to classical discretized representations of signals. Nevertheless, despite their practical success, we still do not understand how INRs represent signals. We propose a ...

IEEE COMPUTER SOC2022

Modelling of AC/DC Interactions of Converter-Interfaced Resources for Harmonic Power-Flow Studies in Microgrids

Mario Paolone, Yihui Zuo, Johanna Kristin Maria Becker, Andreas Martin Kettner

Modern power distribution systems experience a large-scale integration of Converter-Interfaced Distributed Energy Resources (CIDERs). As acknowledged by recent literature, the interaction of individual CIDER components and different CIDERs through the grid ...

2022

Weak nonlinearity for strong non-normality

François Gallaire, Edouard Boujo, Yves-Marie François Ducimetière

We propose a theoretical approach to derive amplitude equations governing the weakly nonlinear evolution of non-normal dynamical systems, when they experience transient growth or respond to harmonic forcing. This approach reconciles the non-modal nature of ...

Cambridge University Press2022

Optically reconfigurable quasi-phase-matching in silicon nitride microresonators

Camille Sophie Brès, Jianqi Hu, Anton Stroganov, Edgars Nitiss

Quasi-phase-matching has long been a widely used approach in nonlinear photonics, enabling efficient parametric frequency conversions such as second-harmonic generation. However, in silicon photonics the task remains challenging, as materials best suited f ...

Nature Publishing Group2022

Data-driven numerical site response

Jean-François Molinari, Antonio Joaquin Garcia Suarez, Sacha Zenon Wattel

Prediction of ground motion triggered by earthquakes is a prime concern for both the seismology community and geotechnical earthquake engineering one. The subfield occupied with such a problem is termed site response analysis (SRA), its one-dimensional fla ...

2022

Non-linear Shubnikov-de Haas oscillations in the self-heating regime

Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo, Xiangwei Huang, Jonas De Jesus Diaz Gomez

We demonstrate a non-linear measurement scheme of the Shubnikov-de Haas effect based on Joule self-heating that builds on ideas of the 3 ?-method used in thin films. While the temperature dependence of the resistance, R(T), of clean metals at low temperatu ...

AIP Publishing2021

Effects of impurities and local behavior characterization using active thermography on solid oxide electrolysis cells

Guillaume Jeanmonod

Ambitious policies are needed from every country to drastically curtail the anthropogenic emission of greenhouse gases responsible for the on-going modification of the earth's climate. A quick transition towards a society fully based on renewable materials ...

EPFL2021

Seeded Multimode Quasi-Phase-Matching in All-Optically Poled Silicon Nitride Waveguides

Camille Sophie Brès, Ozan Yakar, Edgars Nitiss

We demonstrate seeding-enabled all-optical poling of silicon nitride waveguides as short as 5 mm, and account for quasi-phase-matching (QPM) inside the waveguide between the fundamental mode of pump and higher order second-harmonic modes. ...

OSA2021

Discovering Tonal Profiles with Latent Dirichlet Allocation

Martin Alois Rohrmeier, Fabian Claude Moss

Music analysis, in particular harmonic analysis, is concerned with the way pitches are organized in pieces of music, and a range of empirical applications have been developed, for example, for chord recognition or key finding. Naturally, these approaches r ...

2021

Characterization of Real-World Power System Signals in Non-Stationary Conditions using a Dictionary Approach

Mario Paolone, Asja Derviskadic, Guglielmo Frigo, Alexandra Cameron Karpilow

As power grids transition towards low-inertia net-works based on converter-interfaced renewable energy resources, they become increasingly vulnerable to extreme dynamics. Currently, the most advanced methods for signal processing in power systems are embed ...

IEEE2021

Biodegradable Harmonophores for Targeted High-Resolution In Vivo Tumor Imaging

Sylvie Roke, Claire Jacqueline Léa Teulon, Ali Yasin Sonay, Shahed Behzadi, Sine Yaganoglu

Optical imaging probes have played a major role in detecting and monitoring a variety of diseases. In particular, nonlinear optical imaging probes, such as second harmonic generating (SHG) nanoprobes, hold great promise as clinical contrast agents, as they ...

2021

A Data-Driven Fault Location Algorithm Based on the Electromagnetic Time Reversal in Mismatched Media

Mario Paolone, Zhaoyang Wang, Zhe Chen

The classical electromagnetic time reversal (EMTR) fault location method in power systems can be time consuming, especially when a high location accuracy is desired. To cope with this issue, the concept of EMTR in mismatched media has recently been introdu ...

2021