A5023067247- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Laser Design and Applications
- Atomic and Molecular Physics
- Laser Material Processing Techniques
- Ion-surface interactions and analysis
- Diamond and Carbon-based Materials Research
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Magnetic confinement fusion research
- Solid State Laser Technologies
- Particle Accelerators and Free-Electron Lasers
- Nuclear Physics and Applications
- Ocular and Laser Science Research
- Dust and Plasma Wave Phenomena
- Advanced Optical Sensing Technologies
- Planetary Science and Exploration
- Gamma-ray bursts and supernovae
- Orbital Angular Momentum in Optics
- Surface Roughness and Optical Measurements
- Fluid Dynamics and Turbulent Flows
- Advanced Radiotherapy Techniques
- Adaptive optics and wavefront sensing
Imperial College London
2012-2025
John Adams Institute for Accelerator Science
2017-2025
Isaac Newton Institute for Mathematical Sciences
2023-2025
National Institutes for Quantum Science and Technology
2017-2024
Kansai Photon Science Institute
2018-2023
KRI
2018
Japan Science and Technology Agency
2017
Osaka University
2017
National Research Nuclear University MEPhI
2017
Joint Institute for High Temperatures
2017
Abstract Laser-driven ion accelerators can deliver high-energy, high-peak current beams and are thus attracting attention as a compact alternative to conventional accelerators. However, achieving sufficiently high energy levels suitable for applications such radiation therapy remains challenge laser-driven Here we generate proton with spectrally separated high-energy component of up 150 MeV by irradiating solid-density plastic foil targets ultrashort laser pulses from repetitive petawatt...
We report on the acceleration of impurity-free quasimononenergetic proton beams from an initially gaseous hydrogen target driven by intense infrared (λ=10 μm) laser. The front surface was observed optical probing to be forward radiation pressure A beam ∼MeV energy simultaneously recorded with narrow spread (σ∼4%), low normalized emittance (∼8 nm), and negligible background. scaling ratio intensity over density (I/n) confirms that is due shock.
We report experimental evidence for a Rayleigh-Taylor-like instability driven by radiation pressure of an ultraintense (${10}^{21}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) laser pulse. The is witnessed the highly modulated profile accelerated proton beam produced when irradiates 5 nm diamondlike carbon (90% C, 10% H) target. Clear anticorrelation between bubblelike modulations and transmitted further demonstrate role in modulating foil. Measurements modulation wavelength, acceleration...
We report the generation of 63 J broadband pulse energies at 0.1 Hz from J-KAREN-P laser, which is based on an OPCPA/Ti:sapphire hybrid architecture. Pulse compression down to 30 fs indicates a peak power over 1 PW. High temporal contrast 1012 prior main has been demonstrated with 10 output energy. intensities 1022 W/cm2 target by focusing 0.3 PW laser f/1.3 off-axis parabolic mirror have achieved. Fundamental processes matter interaction belong new branch science that will be principal...
J-KAREN-P is a high-power laser facility aiming at the highest beam quality and irradiance for performing state-of-the art experiments frontier of modern science. Here we approached physical limits quality: diffraction limit focal spot bandwidth pulse shape, removing chromatic aberration, angular chirp, wavefront spectral phase distortions. We performed accurate measurements peak fluence after an f/1.3 off-axis parabolic mirror under full amplification power 0.3 PW attenuated with ten...
Abstract We report on experimental investigations of proton acceleration from solid foils irradiated with PW-class laser-pulses, where highest cut-off energies were achieved for temporal pulse parameters that varied significantly those an ideally Fourier transform limited (FTL) pulse. Controlled spectral phase modulation the driver laser by means acousto-optic programmable dispersive filter enabled us to manipulate shape last picoseconds around main and study effect thin foil targets. The...
Laser-driven ion sources are a rapidly developing technology producing high energy, peak current beams. Their suitability for applications, such as compact medical accelerators, motivates development of robust acceleration schemes using widely available repetitive ultraintense femtosecond lasers. These applications not only require beam but also place demanding requirements on the source stability and controllability. This can be seriously affected by laser temporal contrast, precluding...
In this paper, high temperature (~10 keV) solid density silver plasma is generated experimentally by exposing a thin foil to the extreme fields of tightly focused high-power laser. The authors demonstrate that such an efficient source highly charged, energy heavy ions, with generation ultra-strong electric
Abstract We present the development and characterization of a high-stability, multi-material, multi-thickness tape-drive target for laser-driven acceleration at repetition rates up to 100 Hz. The tape surface position was measured be stable on sub-micrometre scale, compatible with high-numerical aperture focusing geometries required achieve relativistic intensity interactions pulse energy available in current multi-Hz near-future higher repetition-rate lasers ( $>$ kHz). Long-term drift...
Abstract The interaction of relativistically intense lasers with opaque targets represents a highly non-linear, multi-dimensional parameter space. This limits the utility sequential 1D scanning experimental parameters for optimization secondary radiation, although to-date this has been accepted methodology due to low data acquisition rates. High repetition-rate (HRR) augmented by machine learning present valuable opportunity efficient source optimization. Here, an automated, HRR-compatible...
Ion acceleration driven by the interaction of an ultraintense (2 × 1020 W cm−2) laser pulse with ultrathin ( nm) foil target is experimentally and numerically investigated. Protons accelerated sheath fields via radiation pressure are angularly separated identified based on their directionality signature features (e.g. transverse instabilities) in measured spatial-intensity distribution. A low divergence, high energy proton component also detected when heated electrons expand becomes...
Acceleration of particles from the interaction ultraintense laser pulses up to 5×10^{21} W cm^{-2} with thin foils is investigated experimentally. The electron beam parameters varied decreasing spot size, not just intensity, resulting in reduced temperatures and divergence. In particular, temperature saturated due insufficient acceleration length tightly focused spot. These dependencies affected sheath-accelerated protons, which showed poorer spot-size scaling than widely used laws. It...
We described the output performance and temporal quality enhancement of J-KAREN-P petawatt laser facility. After wavefront correction using a deformable mirror, focusing with an f/1.3 off-axis parabolic mirror delivered peak intensity 1022 W/cm2 at 0.3 PW power levels. Technologies to improve contrast were investigated tested. The origins pre-pulses generated by post-pulses identified elimination most removal wedged optics was achieved. A cascaded femtosecond optical parametric amplifier...
By tailoring the wavefront of laser pulse used in a laser-wakefield accelerator, we show that properties x-rays produced due to electron beam’s betatron oscillations plasma can be controlled. creating with coma, find critical energy synchrotronlike x-ray spectrum significantly increased. The coma does not substantially change beam, but increase its divergence and produces an energy-dependent exit angle, indicating changes are beam's oscillation amplitude within wakefield.
We report on reproducible shock acceleration from irradiation of a λ=10 μm CO_{2} laser optically shaped H_{2} and He gas targets. A low energy prepulse (I≲10^{14} W cm^{-2}) is used to drive blast wave inside the target, creating steepened, variable density gradient. This followed, after 25 ns, by high intensity pulse (I>10^{16} that produces an electrostatic collisionless shock. Upstream ions are accelerated for narrow range energies. For long gradients (≳40 μm), broadband beams He^{+}...
The generation of a plasma with an ultrahigh energy density 1.2 GJ/cm3 (which corresponds to about 12 Gbar pressure) is investigated by irradiating thin stainless-steel foils high-contrast femtosecond laser pulses relativistic intensities up 1022 W/cm2. parameters are determined X-ray spectroscopy. results show that most the absorbed at solid density, indicating no pre-plasma generated in current experimental setup.
Spectrally-peaked proton beams of high charge (, , nC ) have been observed from the interaction an intense laser ( W cm−2) with ultrathin CH foils, as measured by spectrally-resolved full beam profiles. These are reproducibly generated for foil thicknesses 5–100 nm, and exhibit narrowing divergence decreasing target thickness down to 5 nm. Simulations demonstrate that narrow energy spread feature is a result buffered acceleration protons. The radiation pressure at front results in asymmetric...
Abstract We have experimentally improved the temporal contrast of petawatt J-KAREN-P laser facility. investigated how generation pre-pulses by post-pulses changes due to overlap between stretched pulse and post-pulse in a chirped-pulse amplification system. shown that time at which pre-pulse is generated its shape are related difference main post-pulse. With this investigation, we found identified origins demonstrated removal most eliminating with wedged optics. also impact stretcher optics...
We report on the measurement of filamented transport laser-generated fast electron beams in near-critical density plasma. A relativistic intensity long-wave-infrared laser irradiated a hydrodynamically shaped helium gas flow at an n_{e}≃10^{25} m^{-3}, generating large flux electrons that propagated beyond critical surface. The beam-to-background ratio was sufficiently high to drive growth Weibel-like filamentation, which measured by optical probing extend up 800 μm with radii ∼10 μm....
Abstract Laser-plasma acceleration of protons offers a compact, ultra-fast alternative to conventional techniques, and is being widely pursued for potential applications in medicine, industry fundamental science. Creating stable, collimated beam at high repetition rates presents key challenge. Here, we demonstrate the generation multi-MeV proton beams from fast-replenishing ambient-temperature liquid sheet. The has an unprecedentedly low divergence 1° (≤20 mrad), resulting magnetic...
We report on the characterization of specular reflection 50 fs laser pulses in intensity range 1017–1021 W cm−2 obliquely incident with p-polarization onto solid density plasmas. These measurements show that absorbed energy fraction remains approximately constant and second harmonic generation (SHG) achieves efficiencies 22±8% for intensities approaching 1021 cm−2. A simple model based relativistic oscillating mirror concept reproduces observed scaling, indicating this is dominant process...
A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The profiler uses differential filtering to provide coarse energy resolution a flexible design allow optimisation expected range trade-off between spatial depending on the application. plastic scintillator detector, imaged with standard 12-bit scientific camera, allows data be taken at rate. An algorithm encompassing non-linearity is...
Next generation intense, short-pulse laser facilities require new high repetition rate diagnostics for the detection of ionizing radiation. We have designed a scintillator-based ion beam profiler capable measuring transverse profile number discrete energy ranges. The optical response and emission characteristics four common plastic scintillators has been investigated range proton energies fluxes. scintillator light output (for 1 MeV > E<sub>p</sub> < 28 MeV) was found to non-linear...