When a terawatt-peak-power laser beam is focused into gas jet, an electron plasma wave, driven by forward Raman scattering, observed to accelerate naturally collimated of electrons relativistic energies (up 10 9 total electrons, with energy distribution maximizing at 2 megaelectron volts, transverse emittance as low 1 millimeter-milliradian, and field gradient up gigaelectron volts per centimeter). Electron acceleration the appearance high-frequency modulations in transmitted light spectrum...

Acceleration of electrons to relativistic energies by a multidimensional self-modulated laser wakefield is discussed. Above power threshold, relativistically self-guided channel from an intense ultrashort pulse ( $I\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{18}\mathrm{W}/{\mathrm{cm}}^{2}$, $\ensuremath{\lambda}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1\ensuremath{\mu}\mathrm{m}$, $\ensuremath{\tau}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}400\mathrm{fs}$)...

Using interferometry, we investigate the dynamics of interaction a relativistically intense 4-TW, 400-fs laser pulse with He gas jet. We observe stable plasma channel 1 mm long and less than 30 microm in diameter, radial gradient electron density approximately 5 x 10(22) cm(-4) an on-axis ten times its maximum value 8 10(19) cm(-3). A high velocity surrounding ionization 3.8 10(8) cm/s has been observed after formation, it is attributed to fast ions expelled from propagating radially...

Enhancement of relativistic third-harmonic generation by using an optically preformed periodic plasma waveguide was achieved. Resonant dependence harmonic intensity on density and modulation parameters observed, which is a distinct characteristic quasi-phase-matching. The results demonstrate the potential modulated in high-field applications.

An on-axis plasma density depression channel was observed during and after the passage of a relativistically ponderomotively self-guided laser pulse through plasma. Optical interferometry used to produce time-resolved distributions, revealing formation waveguide. These results were complemented by guiding collinear trailing pulse.

The temporal envelope of plasma density oscillations in the wake an intense ( $I\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{18}\mathrm{W}/{\mathrm{cm}}^{2}$, $\ensuremath{\lambda}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1\ensuremath{\mu}\mathrm{m}$) laser pulse (400 fs) is measured using forward Thomson scattering from a copropagating, frequency-doubled probe pulse. wakefield fully ionized helium...

By using a laser-induced transient density ramp, we demonstrate self-injection of electrons in self-modulated laser-wakefield accelerator with spatial localization. The number injected reaches 1.7 x 10(8). ramp is produced by prepulse propagating transversely to drill depression channel via ionization and expansion. same mechanism injection comparable efficiency also demonstrated transverse plasma waveguide driven Coulomb explosion.

A tomographic diagnosis method was developed to systematically resolve the injection and acceleration processes of a monoenergetic electron beam in laser-wakefield accelerator. It found that all electrons are injected at same location plasma column accelerated from 5 55 MeV energy 200 microm distance. This is direct measurement real gradient accelerator, experimental data consistent with model transverse wave breaking loading for injection.

Fabrication of periodic transient-density structures in a gas jet with boundary scale length approaching 10μm was demonstrated. This achieved by passing an ultrashort high-intensity laser pulse through patterned mask and imaging the onto target plane. Gas/plasma density at laser-irradiated regions drops as result hydrodynamic expansion following ionization heating pulse. The fabrication gas/plasma such scheme is essential step development plasma photonic devices for applications high-field physics.

This study presents a decentralised intelligent double integral sliding-mode control (IDISMC) system, which consists of five IDISMCs, to regulate and stabilise fully suspended five-degree-of-freedom (DOF) active magnetic bearing (AMB) system. The system structure drive with differential driving mode (DDM) are introduced first. Then, the decoupled dynamic model five-DOF AMB is analysed for design control. Moreover, (ISMC) designed based on considering existences uncertainties. Furthermore,...

For commercialization of a solid oxide fuel cell, it is vital to develop cathode materials with optimal microstructure in order overcome the trade-off between lower operation temperature and higher oxygen reduction reaction (ORR) rate conductivity. In this work, we design synthesize cost-effective La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) nanofibers decorated uniformly distributed NiO nanoparticles as protonic ceramic electrochemical cells. With an appropriate decoration tune ORR activity hierarchical...

Phase-matched relativistic harmonic generation in plasmas is observed for the first time. Third-harmonic light detected and discriminated spectrally angularly from harmonics generated competing processes. Its angular pattern a narrow forward-directed cone, which consistent with phase matching of high-order transverse mode plasma. The signal level found to be on same order magnitude circularly polarized pump pulse as linearly pulse.

Backward Raman amplification of a short laser pulse in plasma waveguide is demonstrated. With guided seed $0.8\mathrm{\text{\ensuremath{-}}}\ensuremath{\mu}\mathrm{J}$ energy and pump 345-mJ 9-mm-long optically preformed waveguide, 910-fold achieved. Heating the by long identified to be key issue for plasma-waveguide-based backward amplifiers.

An analysis of passive mode locking with the intracavity self-focusing effect is presented, and self-starting issue addressed. The shows that initial pulse-shortening force this mechanism too weak to start from beating or noise how it can be greatly enhanced a dilute dye saturable absorber in cavity. This also pulse-width evolution related cw mode-locking lasers.

An efficient method for generating extended plasma waveguides is developed by using the axicon lens in conjunction with ignitor-heater scheme. The short-pulse ignitor generates seed electrons multiphoton ionization, and long-pulse heater expands inverse bremsstrahlung heating builds up density barrier collisional ionization. A 1.2-cm-long waveguide generated pure Ar gas a total energy of only 100 mJ. Evolution profile measured time-resolved interferometry to show forming process how it can...

Programmable fabrication of longitudinal spatial structures in a gas jet was achieved by using laser machining with liquid-crystal light modulator as the pattern mask. By this technique single-shot arbitrary and/or plasma is demonstrated, which establishes crucial step toward raising designs and applications high-field devices to level adaptive feedback optimization.

The catalyst layers for polymer-electrolyte-membrane (PEM) fuel cells were fabricated by deposition of platinum directly onto the gas diffusion layer using pulsed laser (PLD). This technique reduced number steps required to synthesize and amount Pt loading required. PEM with various loadings cathode investigated. With a 100 μ g·cm − 2 , current density single cell reached 1205 mA·cm at 0.6 V, which was close that an E-TEK (trademark) Pt/C electrode 400 . Furthermore, both electrodes prepared...

Tomographic measurement of high harmonic generation in a cluster jet was demonstrated by programming the density distribution with laser machining technique. The growth energy propagation pump pulse resolved scanning end argon path pulse. A downstream shift position rapid and decrease slope increasing backing pressure as results changes phase-matching condition were observed, which explains presence an optimal pressure.

Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing is achieved by using an optically preformed plasma waveguide. With a 9-mm-long pure krypton waveguide prepared the axicon-ignitor-heater scheme, at 32.8 nm enhanced 400 folds relative to case without An output level 8 x 10(10) photon/shot reached energy conversion efficiency 2 10(-6). The same method used achieve in gas jet for high-threshold low-gain transition 46.9 neonlike argon.