A5016793817- Advanced X-ray Imaging Techniques
- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Particle Accelerators and Free-Electron Lasers
- Advanced Electron Microscopy Techniques and Applications
- Advanced Fiber Laser Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Laser Design and Applications
- Spectroscopy and Quantum Chemical Studies
- Electron and X-Ray Spectroscopy Techniques
- Pulsed Power Technology Applications
- Photochemistry and Electron Transfer Studies
- Advanced Surface Polishing Techniques
- Photonic and Optical Devices
- Laser Material Processing Techniques
- Gyrotron and Vacuum Electronics Research
- Advanced Chemical Physics Studies
- Laser-induced spectroscopy and plasma
- Terahertz technology and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Dose and Imaging
- Advanced Materials Characterization Techniques
- Solid State Laser Technologies
- Advanced Radiotherapy Techniques
- Bacterial Identification and Susceptibility Testing
SLAC National Accelerator Laboratory
2021-2025
University of California, Los Angeles
2015-2019
Hospital de Câncer de Barretos
2012
Universidade de Ribeirão Preto
2012
Universidade de São Paulo
2012
Attosecond-pump/attosecond-probe experiments have long been sought as the most straightforward method for observing electron dynamics in real time. Although there has much success with overlapped near-infrared femtosecond and extreme ultraviolet attosecond pulses combined theory, true attosecond-pump/attosecond-probe limited. We used a synchronized x-ray pulse pair from an free-electron laser to study electronic response valence ionization liquid water through all transient absorption...
Ultralow emittance (≤20 nm, normalized) electron beams with 105 electrons per bunch are obtained by tightly focusing an ultrafast (∼100 fs) laser pulse on the cathode of a 1.6 cell radio frequency photoinjector. Taking advantage small initial longitudinal emittance, downstream velocity bunching cavity is used to compress beam <10 fs rms length. The measurement performed using thick high-voltage deflecting which shown be well suited measure ultrashort durations beams, provided that reaches...
Abstract Advances in ultrafast laser technology and nanofabrication have enabled a new class of particle accelerator based upon miniaturized laser-driven photonic structures. However, developing useful on this approach requires control the dynamics at field intensities approaching damage limit. We measure acceleration fused silica dielectric driven by fields up to 9 GV m −1 observe record 1.8 accelerating mode. At these is beyond its linear response self-phase modulation changes phase...
Using an 800 nm, 45 fs pulse-front-tilted laser we demonstrate a record 315 keV energy gain in dual grating dielectric accelerator (DLA) and average accelerating gradients of 560 MV/m over 0.5 mm. These results open new regime DLA characterized by significant evolution the beam distribution longitudinal phase space, corresponding to >1/4 synchrotron oscillation. By tilting wavefront control resonant velocity observe net gain, indicating that tapered optical could be used achieve very high gain.
The detailed understanding of electronic coherence in quantum systems requires measurements on the attosecond timescale. Attosecond x-ray pulses enable study core-excited molecular systems. Here we report coherent motion electrons 1,1-difluoroethylene ion following ionization <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>K</a:mi></a:math> shell two nonequivalent carbon sites with a subfemtosecond pulse. Using angular streaking technique to track Auger-Meitner...
We propose a scheme allowing coherent shaping, i.e., controlling both the amplitude and phase, of attosecond x-ray pulses at free-electron lasers. show that by seeding laser with short seed overfills amplification bandwidth, one can shape Wigner function pulse undulator taper profile. The examples controllable pairs trains, as well isolated spectrotemporally shaped very broad bandwidths are examined in detail. Existing lasers achieve these experimental conditions two-stage cascade, which is...
We present the results of an experiment where a short focal length (~ 1.3 cm) permanent magnet electron lens is used to image micron-size features metal sample in single shot, using ultra- high brightness ps-long 4 MeV beam from radiofrequency photoinjector. Magnifcation ratios excess 30x were obtained triplet compact, small gap (3.5 mm), Halbach-style quadrupoles with nearly 600 T/m field gradients. These pave way to- wards shot time-resolved microscopy and open new opportunities applications beams.
Abstract X-ray free-electron lasers are sources of coherent, high-intensity X-rays with numerous applications in ultra-fast measurements and dynamic structural imaging. Due to the stochastic nature self-amplified spontaneous emission process difficulty controlling injection electrons, output pulses exhibit significant noise limited temporal coherence. Standard measurement techniques used for characterizing two-coloured challenging, as they either invasive or diagnostically expensive. In this...
Electron beam shaping allows the control of temporal properties x-ray free-electron laser pulses from femtosecond to attosecond timescales. Here, we demonstrate use a heater shape electron bunches and enable generation pulses. We that this method can be applied in selective way, targeted subset while leaving remaining unchanged. This experiment enables delivery shaped multiple undulator beamlines, with pulse tailored specialized scientific applications.
Active longitudinal beam optics can help free-electron laser facilities achieve cutting edge performance by optimizing the to produce multicolor pulses, suppress caustics, or support attosecond lasing. As next generation of superconducting accelerators comes online, there is a need find new elements which both operate at high-beam power and offer multiplexing capabilities MHz repetition rate. Laser heater shaping promises satisfy criteria imparting programmable slice-energy spread on...
This paper details the development of a single-shot diagnostic technique for 4D average and core phase space densities low-charge, high-brightness electron beams, based on analysis shadow point-projection images metal grids. is similar to standard pepper pot method, although it allows much greater transmission beam therefore more suitable low-charge beams. Transverse coupling terms are included in analysis, allowing complete transverse matrix be reconstructed. The information extremely...
In this paper we discuss a relative time-of-arrival measurement scheme between an electron beam and mid-infrared laser pulse based on the electron-beam controlled transmission in semiconductor materials. This technique can be used as time-stamping diagnostic ultrafast diffraction or microscopy. particular, our characterization of Germanium demonstrates that sub-ps sensitivity could achieved single shot with very low charge beams (&lt;1 pC). Detailed measurements function wavelength offer...
We report the measurement of impulsive stimulated x-ray Raman scattering in neutral liquid water. An attosecond pulse drives excitations an electronic wavepacket water molecules. The process comprises two steps: a transition to core-excited states near oxygen atoms accompanied by valence-excited states. Thus, is impulsively created at specific atomic site within few hundred attoseconds through nonlinear interaction between and pulse. observe this signature intensity-dependent Stokes sideband...
We present a methodology for designing and measuring pulse front tilt in an ultrafast laser use dielectric acceleration. Previous research into accelerating modules has focused on high gradients novel structures, but done so only short electron-laser coupling lengths. Here we demonstrate optical design to extend the laser-electron interaction 1mm.
The use of sub-wavelength metal structures to locally enhance high frequency electromagnetic fields, generally known as plasmonics, enables breakthrough opportunities across diverse fields research such nonlinear optics, biosensing, photovoltaics and others. Here we study the application metallic resonators tuned in THz range for manipulation diagnostics relativistic electron beams. In this work, report on a double-sided split-ring structure driven by near single cycle field generated...
When a femtosecond duration and hundreds of kiloampere peak current electron beam traverses the vacuum high-density plasma interface, new process, that we call relativistic transition radiation (RTR), generates an intense $\ensuremath{\sim}100$ as pulse containing $\ensuremath{\sim}1$ terawatt power coherent ultraviolet (VUV) accompanied by several smaller satellite pulses. This inherits radial polarization incident field has ring intensity distribution. RTR is emitted when density...
Dielectric Laser Acceleration (DLA) achieves the highest gradients among structure-based electron accelerators. The use of dielectrics increases breakdown field limit, and thus achievable gradient, by a factor at least 10 in comparison to metals. Experimental demonstrations DLA 2013 led Accelerator on Chip International Program (ACHIP), funded Gordon Betty Moore Foundation. In ACHIP, our main goal is build an accelerator silicon chip, which can accelerate electrons from below 100 keV above 1...
Laser powered dielectric structures achieve high-gradient particle acceleration by taking advantage of modern laser technology capable producing electric fields in excess 10GV/m. These can drive the bulk beyond its linear response, and break phase synchronicity between accelerating field electrons. We show how control pulse dispersion be used to compensate effect self-phase modulation maximize energy gain accelerator.In our experiment, a high brightness 8MeV e-beam is probe 1.8GV/m...
Accurate measurements of the x-ray pulse duration produced by free-electron lasers (XFELs) typically rely on longitudinal electron beam phase space diagnostics, e.g., an x-band transverse deflecting cavity (XTCAV). An alternative group methods is based radiation statistics and spectral correlations. In this paper, we present a statistical analysis FEL which extends previous technique Lutman et al. [Phys. Rev. ST Accel. Beams 15, 030705 (2012)], including energy chirp in gain model. doing so,...
Femtosecond laser pulses can be used to achieve desired GV m−1 electron accelerating gradients in dielectric accelerator structures. Extending this interaction over a distance exceeding 1 mm may require the use of focusing Using simulations, we motivate new structure driven by short pulses. In contrast previous microstructures, surface has three heights. simulation, show that peak field gradient equivalent 2.9 MT m−1.