A5020773490- Laser-Matter Interactions and Applications
- Advanced Fiber Laser Technologies
- Advanced Electron Microscopy Techniques and Applications
- Orbital Angular Momentum in Optics
- Gold and Silver Nanoparticles Synthesis and Applications
- Near-Field Optical Microscopy
- Photonic and Optical Devices
- Spectroscopy and Quantum Chemical Studies
- Electron and X-Ray Spectroscopy Techniques
- Advanced Fluorescence Microscopy Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Quantum Structures and Devices
- Mass Spectrometry Techniques and Applications
- Photonic Crystal and Fiber Optics
- Ion-surface interactions and analysis
- Terahertz technology and applications
- Advancements in Photolithography Techniques
- Nanowire Synthesis and Applications
- Gyrotron and Vacuum Electronics Research
- Advanced X-ray Imaging Techniques
- Optical Coatings and Gratings
- Mechanical and Optical Resonators
- Advanced biosensing and bioanalysis techniques
- Spectroscopy and Laser Applications
- Thermal Radiation and Cooling Technologies
University of California, Davis
2020-2024
Massachusetts Institute of Technology
2010-2020
Northrop Grumman (United States)
2017-2019
Universität Hamburg
2016-2019
Cambridge Electronics (United States)
2017
Center for Free-Electron Laser Science
2016
Science Research Laboratory
2013
X-ray crystallography is one of the main methods to determine atomic-resolution 3D images whole spectrum molecules ranging from small inorganic clusters large protein complexes consisting hundred-thousands atoms that constitute macromolecular machinery life. Life not static, and unravelling structure dynamics most important reactions in chemistry biology essential uncover their mechanism. Many these reactions, including photosynthesis which drives our biosphere, are light induced occur on...
We propose the use of interaction-free quantum measurements with electrons to eliminate sample damage in electron microscopy. This might allow noninvasive molecular-resolution imaging. show possibility such presence experimentally measured decoherence rates and using a scheme based on existing charged particle trapping techniques.
Understanding plasmon-mediated electron emission and energy transfer on the nanometer length scale is critical to controlling light–matter interactions at nanoscale dimensions. In a high-resolution lithographic material, lead chemical transformations. this work, we employ such transformations in two different electron-beam lithography resists, poly(methyl methacrylate) (PMMA) hydrogen silsesquioxane (HSQ), map local with resolution from plasmonic nanoantennas excited by femtosecond laser...
Ultrafast light-matter interactions lead to optical-field-driven photocurrents with an attosecond-level temporal response. These can be used detect the carrier-envelope-phase (CEP) of short optical pulses, and could utilized create optical-frequency, petahertz (PHz) electronics for information processing. Despite recent reports on in various nanoscale solid-state materials, little has been done examining large-scale integration these devices. In this work, we demonstrate enhanced, on-chip...
We report the synthesis of a nearly single-cycle (3.7 fs), ultrafast optical pulse train at 78 MHz from coherent combination passively mode-locked Ti:sapphire laser (6 fs pulses) and fiber supercontinuum (1-1.4 μm, with 8 pulses). The is achieved via orthogonal, attosecond-precision synchronization both envelope timing carrier phase using balanced cross-correlation homodyne detection, respectively. resulting envelope, which only 1.1 cycles in duration, retrieved two-dimensional spectral...
We report on a novel class of higher-order Bessel-Gauss beams in which the well-known beam is fundamental mode and azimuthally symmetric Laguerre-Gaussian are special cases. find these by superimposing decentered Hermite-Gaussian beams. show analytically experimentally that resemble eigenmodes optical resonators consisting aspheric mirrors. This work relevant for many applications particular more recently proposed high-intensity enhancement cavities strong-field physics applications.
Strong‐field photoemission from silicon field emitter arrays is investigated experimentally and results are explained using a “simple‐man” optical‐field emission model. Spectra collected throughout an in‐situ laser annealing process, leading to red‐shift in emitted electron energy along with increase yield. After the high plateau formed which through re‐scattering tip surface.
Abstract We analytically describe the noise properties of a heralded electron source made from standard gun, weak photonic coupler, single photon counter, and an energy filter. sub-Poissonian statistics source, engineering requirements for efficient heralding, several potential applications. use simple models beam processes to demonstrate advantages which are situational, but potentially significant in lithography scanning microscopy.
We introduce Bessel-Gauss beam enhancement cavities that may circumvent the major obstacles to more efficient cavity-enhanced high-field physics such as high-harmonic generation. The basic properties of beams are reviewed and their transformation through simple optical systems (consisting spherical conical elements) presented. A general cavity design strategy is outlined, a particular geometry, confocal cavity, analyzed in detail. numerically simulate present an example with 300 MHz...
We report on a few-cycle, carrier–envelope-phase-stable laser source based supercontinuum generation driven by an amplified Er:fiber-based system. Laser pulses from Er:fiber oscillator are amplified, and these generate stable in highly nonlinear optical fiber. The short- long-wavelength tails of this continuum used f-to-2f interferometer to stabilize the carrier–envelope phase (CEP) via acousto-optic modulator. Compressing central part continuum, we train CEP-stabilized with wavelength 1170...
We derive solutions for radially polarized Bessel-Gauss beams in free-space by superimposing decentered Gaussian with differing polarization states. numerically show that the analytical result is applicable even large semi-aperture angles, and we experimentally confirm expression employing a fiber-based mode-converter.
Abstract We demonstrate an on-chip, optoelectronic device capable of sampling arbitrary, low-energy, near-infrared waveforms under ambient conditions with sub-optical-cycle resolution. Our detector uses field-driven photoemission from resonant nanoantennas to create attosecond electron bursts that probe the electric field weak optical waveforms. Using these devices, we sampled fields ~5 fJ (6.4 MV m -1 ), few-cycle, using ~50 pJ (0.64 GV ) driving pulses. Beyond waveforms, our measurements...
An enhancement cavity design with significant intensity gain from the mirror surfaces to focus and larger than millimeter sized apertures in mirrors is presented. A continuous-wave version of demonstrated.
Electromagnetic radiation in the mid-infrared portion of spectrum is critical for sensing and spectroscopy. However, detecting challenging. Typically, detectors rely on photon absorption exotic semiconductor structures, or they use relatively slow (low-bandwidth) thermal effects. Here, we demonstrate detection long-wave infrared laser pulses metal-semiconductor-metal photodiode structures. The span spectral range from 7-12 microns have pulse energies <1 nJ. Our consist gold titanium...
We investigate how free-electrons can excite modes in nearby photonic waveguides. Using particle-in-cell simulations, we explore a free-electron packet couple energy into multiple, velocity-matched of an adjacent silicon waveguide.
We use 2.4-micron laser pulses to produce second-harmonic generation via random quasi-phase-matching in ZnS. Using a frequency-resolved optical gating system, we reconstruct the complex temporal profile of pulses.
The interaction between free electrons and photons in electron microscopes offers unique opportunities for microscopy quantum science. For example, modulating beams with multiple laser excitations, researchers have demonstrated a novel near-field microscope, capable of probing electromagnetic excitations on the nanometer spatial scale attosecond (10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−18</sup> s) temporal range [see D. Nabben et...
We analytically describe the noise properties of a heralded electron source made from standard gun, weak photonic coupler, single photon counter, and an energy filter. argue traditional heralding figure merit, Klyshko efficiency, is insufficient statistic for characterizing performance in dose-control dose-limited applications. Instead, we sub-Poissonian statistics using fractional reduction variance increase Fisher Information. Using these figures discuss engineering requirements efficient...
This work demonstrates electron energy loss spectroscopy of 2D materials in a 1-30 keV microscope, observing 100-times stronger electron-matter coupling relative to 125 microscopes. We observe that the universal curve relating beam scattering holds for transition from bulk graphite graphene, albeit with scale factor. calculate optimal most and optical nanostructures falls this range, concluding such systems will greatly benefit use previously unexplored regime.
We investigate silicon waveguides with subwavelength-scale modulation for applications in free-electron-photon interactions. The enables velocity matching and efficient interactions between low-energy electrons co-propagating photons. Specifically, we design a subwavelength-grating (SWG) waveguide 23-keV free ≈1500-nm SWG electron system exhibit coupling coefficient of | g Qu = 0.23, as corroborate time-domain, particle-in-cell simulations, the operates backward-wave oscillator. Overall, our...