A5054120662- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Laser Material Processing Techniques
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Solid State Laser Technologies
- Ocular and Laser Science Research
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Advanced Surface Polishing Techniques
- Semiconductor materials and devices
- Nonlinear Optical Materials Studies
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Diamond and Carbon-based Materials Research
- Integrated Circuits and Semiconductor Failure Analysis
- Orbital Angular Momentum in Optics
- Photonic Crystal and Fiber Optics
- Semiconductor Quantum Structures and Devices
- Photonic and Optical Devices
- Electronic and Structural Properties of Oxides
- Advanced Optical Sensing Technologies
- Plasma Diagnostics and Applications
- Spectroscopy and Quantum Chemical Studies
The Ohio State University
2015-2024
University College London
2024
Royal Holloway University of London
2024
King's College London
2024
University of Chicago
2024
The University of Queensland
2024
Virginia Tech
2024
University of Oxford
2024
Monash University
2024
Columbus Center
2023
In the 2015 review paper ‘Petawatt Class Lasers Worldwide’ a comprehensive overview of current status high-power facilities ${>}200~\text{TW}$ was presented. This largely based on facility specifications, with some description their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With 2018 Nobel Prize Physics being awarded to Professors Donna Strickland Gerard Mourou development technique chirped...
Abstract Time-dependent nonlinear media, such as rapidly generated plasmas produced via laser ionization of gases, can increase the energy individual photons and generate tunable high-order harmonic pulses. This phenomenon, known photon acceleration, has traditionally required extreme-intensity pulses macroscopic propagation lengths. Here, we report on a novel material—an ultrathin semiconductor metasurface—that exhibits efficient acceleration at low intensities. We observe signature...
We report on the first successful proof-of-principle experiment to manipulate laser-matter interactions microscale using highly ordered Si microwire arrays. The interaction of a high contrast short pulse laser with flat target via periodic microwires yields substantial enhancement in both total and cut-off energies produced electron beam. self generated electric magnetic fields behave as an electromagnetic lens that confines guides electrons between they acquire relativistic direct...
Modern electronics are founded on switching the electrical signal by radio frequency electromagnetic fields nanosecond time scale, limiting information processing to gigahertz speed. Recently, optical switches have been demonstrated using terahertz and ultrafast laser pulses control enhance speed picosecond a few hundred femtoseconds scale. Here, we exploit reflectivity modulation of fused silica dielectric system in strong light field demonstrate (ON/OFF) with attosecond resolution....
Leakage currents and dielectric breakdown were studied in MIS capacitors of metal-aluminum oxide-silicon. The aluminum oxide was produced by thermally oxidizing AlN at 800-1160/spl deg/C under dry O/sub 2/ conditions. films deposited RF magnetron sputtering on p-type Si (100) substrates. Thermal oxidation Al/sub 2/O/sub 3/ with a thickness structure that depended the process time temperature. exhibited charge regimes accumulation, depletion, inversion semiconductor surface. best electrical...
Laser-induced femtosecond damage thresholds of Au and Ag coated pulse compression gratings were measured using 800 nm laser pulses ranging in duration from 30 to 200 fs. These differ conventional metal-on-photoresist that the patterns are generated by etching fused silica substrate directly. After etching, metal overcoating was optimized based on diffraction efficiency threshold considerations. The experiment these performed under vacuum for single-shot damage. Single-shot threshold, where...
Laser acceleration of ions to ≳MeV energies has been achieved on a variety Petawatt laser systems, raising the prospect ion beam applications using compact ultra-intense technology. However, translation from proof-of-concept experiment into real-world application requires MeV-scale and an appreciable repetition rate (>Hz). We demonstrate, for first time, proton up 2 MeV at kHz milli-joule-class short-pulse system. In these experiments, 5 mJ ultrashort-pulse energy is delivered intensity near...
Polycrystalline ZnSe is an exciting source of broadband supercontinuum and high-harmonic generation via random quasi phase matching, exhibiting broad transparency in the mid-infrared (0.5-20 μm). In this work, effects wavelength, pulse power, intensity, propagation length, crystallinity on high harmonic are investigated experimentally using ultrafast pulses. Observed conversion efficiency scales linearly reaching as 36%. For first time to our knowledge, n2 measured for wavelengths ZnSe:...
High-intensity laser–plasma interactions produce a wide array of energetic particles and beams with promising applications. Unfortunately, the high repetition rate average power requirements for many applications are not satisfied by lasers, optics, targets, diagnostics currently employed. Here, we aim to address need high-repetition-rate targets optics through use liquids. A novel nozzle assembly is used generate high-velocity, laminar-flowing liquid microjets which compatible low-vacuum...
We present a fully three-dimensional kinetic framework for modeling intense short pulse lasers interacting with dielectric materials. Our work modifies the open-source Particle-In-Cell (PIC) code EPOCH to include new models molecular photoionization and optical response. use this model laser-induced damage of materials by few-cycle laser pulses. The is benchmarked against experimental results bulk silica targets then applied multi-layer mirrors sequence simulations varying fluence. This...
The chirped pulse amplification technique has enabled the generation of pulses a few femtosecond duration with peak powers multi-Tera and Peta-Watt in near infrared. Its implementation to realize even shorter duration, higher energy, repetition rate laser systems relies on overcoming limitations imposed by damage critical components. In particular, coatings amplifiers post-compression optics have become bottleneck. robustness optical is typically evaluated numerically through steady-state...
${\mathrm{Ne}}^{+}$ to ${\mathrm{Ne}}^{8+}$ ionization yields in ${10}^{14}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$ ${10}^{18}\text{ laser fields are reported over a ${10}^{9}$ dynamic range. A 3D relativistic rescattering model incorporating $(e,2e)$ and $(e,3e)$ electron impact ionization, single- double-excitation is compared the data. For double agreement excellent; however, for higher charge states accounts only 15% of multielectron nonsequential ionization. Rescattering not...
We report on a numerical study of the effects preplasma scale length and laser intensity hot-electron ($\ensuremath{\ge}1\text{ }\text{ }\mathrm{MeV}$) divergence angle using full-scale 2D3V (two dimensional in space, three velocity) simulations including self-consistent laser-plasma interaction photoionization particle-in-cell code LSP. Our show that fast-electron increases approximately linearly with for fixed intensity. On other hand, length, has little effect range between ${10}^{18}$...
Although ultrafast laser materials processing has advanced at a breakneck pace over the last two decades, most applications have been developed with pulses near-IR or visible wavelengths. Recent progress in mid-infrared (MIR) femtosecond source development may create novel capabilities for material processing. This is because, high intensities required such processing, wavelength tuning to longer wavelengths opens pathway special regime of laser-solid interactions. Under these conditions,...
Abstract Femtosecond-laser-assisted material restructuring employs extreme optical intensities to localize the ablation regions. To overcome minimum feature size limit set by wave nature of photons, there is a need for new approaches tailored processing at nanoscale. Here, we report formation deeply-subwavelength features in silicon, enabled localized laser-induced phase explosions prefabricated silicon resonators. Using short trains mid-infrared laser pulses, demonstrate controllable high...
The field ionization cross sections for the L-shell states in argon are presented as measured with pulsed-laser radiation at an intensity of up to ${10}^{19}\mathrm{W}/{\mathrm{cm}}^{2}.$ For ultrahigh intensities, photoelectron continuum dynamics will be relativistic. However, charge-state yields ${\mathrm{Ar}}^{9+}$ ${\mathrm{Ar}}^{16+}$ compare favorably numerical solutions nonrelativistic Schr\"odinger equation and a widely used Ammosov-Delone-Krainov/WKB tunneling model. results...
Experimental results from copper cones irradiated with ultraintense laser light are presented. Spatial images and total yields of CuKα fluorescence were measured as a function the focusing properties. The emission extends into cone approximately 300μm tip cannot be explained by ray tracing including wall absorption. In addition, yield is an order magnitude higher than for equivalent mass foil targets. Indications that physics laser-cone interaction dominated preplasma created long duration,...
Laser induced periodic surface structures (LIPSS or ripples) were generated on single crystal germanium after irradiation with multiple 3 µm femtosecond laser pulses at a 45° angle of incidence. High and low spatial frequency LIPSS (HSFL LSFL, respectively) observed for both s- p-polarized light. The measured LSFL period light was consistent the currently established origination model coupling between plasmon polaritons (SPP) incident pulses. A vector SPP is introduced to explain formation...
We present an experimental demonstration of the efficient acceleration electrons beyond 60 MeV using micro-channel plasma targets. employed a high-contrast, 2.5 J, 32 fs short pulse laser interacting with 5 \mu m inner diameter, 300 long target. The was aligned to be collinear incident pulse, confining majority energy within channel. measured electron spectrum showed large increase cut-off and slope temperature when compared that from 2 flat Copper target, cutoff enhanced by over 2.6 times...
Abstract Large scale laser facilities are needed to advance the energy frontier in high physics and accelerator physics. Laser plasma accelerators core advanced concepts aimed at reaching TeV electron colliders. In these facilities, intense pulses drive plasmas used accelerate electrons energies remarkably short distances. A could principle reach with an accelerating length that is 1000 times shorter than conventional RF based accelerators. Notionally, driven particle beam beyond state of...
We have developed a new type of target for intense laser-matter experiments that offers significant advantages over those currently in use. The targets consist liquid crystal film freely suspended within metal frame. They can be formed rapidly on-demand with thicknesses ranging from nanometers to micrometers, where the particular value is determined by temperature and initial volume as well frame geometry. used this work, 8CB (4'-octyl-4-cyanobiphenyl), has vapor pressure below $10^{-6}$...
A systematic study of few-cycle pulse laser induced damage threshold (LIDT) determination was performed for commercially-available ultra-broadband optics, (i.e. chirped mirrors, silver beamsplitters, etc.) in vacuum and air, single multi-pulse regime (S-on-1). Multi-pulse morphology at fluences below the single-pulse LIDT studied order to investigate mechanisms leading onset damage. Stark morphological contrast observed between sites formed air versus those vacuum. One effect testing...
Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from interaction a single femtosecond laser pulse (pump) with nano-scale groove mechanically formed on single-crystal Cu substrate. The dynamics (0-1200 ps) was captured by diffracting time-delayed, frequency-doubled (probe) nascent LIPSS induced pump an infinity-conjugate setup. ripples are observed form asynchronously, first one forming after 50 ps and...