Direct three-dimensional (3D) laser writing of waveguides is highly advanced in a wide range bandgap materials, but has no equivalent silicon so far. We show that nanosecond single-pass irradiation capable producing channel micro-modifications deep into crystalline silicon. With an appropriate shot overlap, relative change the refractive index exceeding 10−3 obtained without apparent nonuniformity at micrometer scale. Despite remaining challenge propagation losses, we created structures...

Abstract Ultrafast laser welding is a fast, clean, and contactless technique for joining broad range of materials. Nevertheless, this cannot be applied bonding semiconductors metals. By investigating the nonlinear propagation picosecond pulses in silicon, it elucidated how evolution filaments during prevents energy deposition at semiconductor–metal interface. While restrictions imposed by effects usually inhibit countless applications, possibility to perform ultrafast demonstrated. This...

Abstract Laser direct writing is a well-established ablation technology for high-resolution patterning of surfaces, and since the development additive manufacturing, laser processes have also appeared very attractive digital fabrication three-dimensional (3D) objects at macro-scale, from few millimeters to meters. On other hand, laser-induced forward transfer (LIFT) has demonstrated its ability print wide range materials build functional micro-devices. For many years, minimum size...

In-bulk processing of materials by laser radiation has largely evolved over the last decades and still opens up new scientific industrial potentials. The development any in-bulk application relies on knowledge propagation especially volumetric field distribution near focus. Many commercial programs can simulate this, but, to adapt them, or develop methods, one usually must create a specific software. Besides, most time people also need measure actual focus evaluate their assumptions in...

Laser-induced permanent modification inside silicon has been recently demonstrated by using tightly focused nanosecond sources at a 1550 nm wavelength. We have developed quantitative-phase microscope operating in the near-infrared domain to characterize laser-induced modifications deep into silicon. By varying number of applied laser pulses and energy, we observe porous densified regions focal region. The observed changes are associated with refractive index variations |Δn| exceeding 10−3,...

In-volume ultrafast laser direct writing of silicon is generally limited by strong nonlinear propagation effects preventing the production modifications. By using advantageous spectral, temporal, and spatial conditions, we demonstrate that modifications can be repeatably produced inside silicon. Our approach relies on irradiation at $\ensuremath{\approx}2$ $\ensuremath{\mu}\mathrm{m}$ wavelength with temporally distorted femtosecond pulses. These pulses are focused in a way spherical...

When the energy of a short laser pulse is localized in fluid material, flow motion induced that can lead to generation free-surface jets. This nozzle-free jetting process exploited print conductive materials, typically metal nanoparticle inks, but this approach remains limited transfer low viscosity fluids with minimum feature size few micrometers. We introduce dual-laser method achieve reproducible high-aspect-ratio jets from thin solid films. A first irradiation induces melting copper...

In order to control the length of micro-channels ablated at surface dielectrics, we use annular filtering apertures for tailoring depth focus micrometric Gaussian-Bessel beams. We identify experimentally and numerically appropriate beam truncation that promotes a smooth axial distribution intensity with small elongation, suitable processing aspect ratio. Single-shot channel fabrication is demonstrated on front fused silica sample, sub-micron diameter, high-quality opening, few micrometers,...

We demonstrate a structuring method for crystalline silicon using nanosecond laser internal irradiation followed by chemical etching. show dramatic dependence of the etch rate on laser-writing speed. Enhanced isotropic rates laser-induced damage were recently demonstrated with strong acids, but our results add possibility to obtain reduced leading different topographies. Material analyses indicate efficiently produce high-aspect ratio channels, thanks porosities, as well micro-bumps due...

In this paper, we develop a two-grid method (TGM) based on the FEM for 2D nonlinear time fractional two-term mixed sub-diffusion and diffusion wave equations.A algorithm is proposed solving system, which consists of two steps: FE system solved coarse grid, then linearized fine grid by Newton iteration solution.The fully discrete numerical approximation analyzed, where Galerkin finite element space derivatives difference scheme Caputo derivative with order α ∈ (1, 2) α1 (0, 1).Numerical...

The proliferation of renewable generations significantly in power system increases the severity and possibility sub-synchronous oscillations (SSOs) recently. Monitoring SSOs is critical for setting up control strategies mitigating effectively. In many SSO events, oscillation frequency magnitude are time-varying, which brings great challenges to monitoring. This paper proposes an adaptive-reset extended Kalman filter (AREKF) method accurate estimation modes. Two improvements made EKF method....

While ultrafast laser welding is a well-established technique for bonding materials, it not applicable to the silicon–silicon configuration because of nonlinear propagation effects. In article number 2200300, Maxime Chambonneau and co-workers solve this issue by relocating filaments at interface where absorption exalted with metallic nanolayer, yielding remarkable shear joining strength values (>4 MPa).

We use the double-pulse laser-induced forward transfer (DP-LIFT) process, combining a quasi-continuous wave (QCW) and femtosecond (fs) laser pulse to achieve jetting from 1-µm thick copper film.The influence of fs fluence on dynamics liquid is experimentally investigated by time-resolved shadowgraphy theoretically analyzed with simple energy balance model.Different regimes are identified when varying fluence.We demonstrate that adjustment this latter parameter while keeping all others...

While ultrafast laser welding is an appealing technique for bonding transparent workpieces, it not applicable joining silicon samples due to nonlinear propagation effects which dramatically diminishes the possible energy deposition at interface. We demonstrate that these limitations can be circumvented by local absorption enhancement interface thanks metallic nanolayer deposition. By combining resulting exalted with filament relocation during irradiation, efficiently joined. Shear strengths...

Conditions and gain spectra of modulation instability (MI) induced by combined effects self-phase waveguide dispersions are investigated, taking into account the linear loss two-photonic absorption (TPA) silicon-on-insulator (SOI) simultaneously. Formulation for calculating MI is deduced theoretically. Impacts various parameters to analyzed theoretically simulated in detail. Both theoretical analysis simulation show that strong takes place even existence low light power. Linear obviously...

We demonstrate for the first time ultrafast laser welding in silicon–metal and silicon–silicon configurations, with focused infrared picosecond pulses. This achievement relies on accurate characterizations of filamentation silicon nonlinear propagation imaging. In configuration, precompensating focal shift prior to yields bonding strengths > 1 MPa. By combining this filament relocation technique metallic nanolayer deposition at interface exalt energy deposition, similar strength values...