Publications de Jun Wang | EPFL Graph Search

Si and III-nitride based photonic crystal cavities for optical trapping and non-linear optics

The project data will be organised in the following folder system : One main folder for the each subproject : GaN nonlinear optics and Optical trapping Each folder is organised in the following sub-folder system (not all may be used), each with a readme- ...

Zenodo2025

Strain engineering and strain measurement by spring tethers on suspended epitaxial GaN-on-Si photonic crystal devices

Romuald Houdré, Jun Wang

Suspended epitaxial gallium nitride (GaN) on silicon (Si) photonic crystal devices suffer from large residual tensile strain, especially for long waveguides, because fine structures tend to crack due to large stress. By introducing spring-like tethers, des ...

Iop Publishing Ltd2024

Experimental demonstration of attosecond pump-probe spectroscopy with an X-ray free-electron laser

Christoph Bostedt, Zhaoheng Guo, Xiang Li, Jun Wang, Siqi Li, Zhen Zhang

Pump-probe experiments with subfemtosecond resolution are the key to understanding electronic dynamics in quantum systems. Here we demonstrate the generation and control of subfemtosecond pulse pairs from a two-colour X-ray free-electron laser. By measurin ...

Nature Publishing Group2024

The second data release from the European Pulsar Timing Array IV. Implications for massive black holes, dark matter, and the early Universe

Andrii Neronov, Jia Liu, Ke Liu, Jun Wang, Jongmoon Jang

The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases, respectively, with the correlation properties of a gravita ...

EDP SCIENCES S A2024

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

Improved spiking neural network for intershaft bearing fault diagnosis

Jun Wang, Tianfu Li

The intershaft bearing is located between the high and low-pressure rotors of the aero-engine, where the working environment is harsh, the load variation range is large, and the lubrication and heat dissipation are poor. The fault of the intershaft bearing ...

ELSEVIER SCI LTD2022

Enhanced strength and toughness of bulk ultrafine grained Cu by nacre-inspired lamellar structure

Roland Logé, Jun Wang, Chenguang Li

An ultrafine grained (UFG) bulk Cu with a novel nacre-inspired lamellar structure containing nano-bridges and aligned nanopores at inter-lamellar interfaces was fabricated by consolidation of a nanocrystal-attached ultrathin Cu flake powder by spark plasma ...

2020

Annealing hardening and softening of an ultrafine grained Cu-4.5vol.% Al2O3 nanocomposite

Roland Logé, Jun Wang, Chenguang Li, Wei Zeng

Samples from an ultrafine-grained Cu-4.5vol.%Al2O3 nanocomposite rod fabricated by powder compact extrusion were annealed at 400 and 700 degrees C for 15 min respectively, and their microstructure and mechanical properties were investigated. It shows that ...

2020

Efficient second harmonic generation in a doubly resonant photonic crystal cavity based on a bound state in the continuum

Nicolas Grandjean, Romuald Houdré, Jean-François Carlin, Matteo Galli, Jun Wang

Making use of bound states in the continuum, we present experimental results on efficient second harmonic generation in photonic crystal cavities supporting doubly-resonant modes. The second harmonic emission is a vortex beam with radial polarization and e ...

IEEE2020

Doubly resonant second-harmonic generation of a vortex beam from a bound state in the continuum

Romuald Houdré, Nicolas Grandjean, Jun Wang, Jean-François Carlin, Matteo Galli, Momchil Minkov, Marco Clementi

Second-harmonic generation in nonlinear materials can be greatly enhanced by realizing doubly resonant cavities with high quality factors. However, fulfilling such doubly resonant condition in photonic crystal (PhC) slab cavities is a long-standing challen ...

2020