A5035229703- Laser-Matter Interactions and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Information and Cryptography
- Advanced Fiber Laser Technologies
- Quantum Mechanics and Applications
- Ion-surface interactions and analysis
- Electron and X-Ray Spectroscopy Techniques
- Molecular Junctions and Nanostructures
- Optical properties and cooling technologies in crystalline materials
- Advanced Chemical Physics Studies
- Advanced Electron Microscopy Techniques and Applications
- Photonic Crystal and Fiber Optics
- Photocathodes and Microchannel Plates
- Spectroscopy and Laser Applications
- Mass Spectrometry Techniques and Applications
- Advanced Materials Characterization Techniques
- Laser Material Processing Techniques
- Quantum, superfluid, helium dynamics
- Graphene research and applications
- Mechanical and Optical Resonators
- Advanced X-ray Imaging Techniques
- Adhesion, Friction, and Surface Interactions
- Heat Transfer Mechanisms
- Plasma Diagnostics and Applications
- Semiconductor Lasers and Optical Devices
Stony Brook University
2009-2024
Brookhaven National Laboratory
2018
University of Nebraska–Lincoln
2007
We show that a field emission tip electron source is triggered with femtosecond laser pulse can generate pulses shorter than the duration (~100 fs). The process sensitive to power law of intensity, which supports an mechanism based on multiphoton absorption followed by over-the-barrier emission. Observed continuous transitions between laws different orders are indicative processes. also be operated so thermionic processes become significant. Understanding these relevant for production...
We present a detailed description of the design, construction, and performance high-power ultrafast Yb:fiber laser frequency combs in operation our laboratory. discuss two such systems: an 87 MHz, 9 W, 85 fs operating at 1060 nm 80 155 1035 nm. Both are constructed using low-cost, commercially available components, can be assembled only basic tools for cleaving splicing single-mode fibers. describe practical methods achieving characterizing low-noise single-pulse long-term stability from...
Time- and Angle-resolved photoelectron spectroscopy from surfaces can be used to record the dynamics of electrons holes in condensed matter on ultrafast time scales. However, photoemission experiments using extreme-ultraviolet (XUV) light have previously been limited by either space-charge effects, low photon flux, or tuning range. In this article, we describe XUV with up 5 nA average sample current a tunable cavity-enhanced high-harmonic source operating at 88 MHz repetition rate. The...
This Letter reports the demonstration of laser cooling without spontaneous emission, and thereby addresses a significant controversy. It works by restricting atom-light interaction to time short compared cycle absorption followed natural decay. is achieved using bichromatic force on an atomic transition with relatively long excited state lifetime so that emission effects are minimized. The observed width one-dimensional velocity distribution reduced ×2 reducing "temperature" ×4. Moreover,...
The unique optical properties of graphene, with broadband absorption and ultrafast response, make it a critical component optoelectronic spintronic devices. Using time-resolved momentum microscopy high data rate dynamic range, we report momentum-space measurements electrons promoted to the graphene conduction band visible light their subsequent relaxation. We observe pronounced nonthermal distribution nascent photoexcited lattice pseudospin polarization in remarkable agreement results simple...
It is widely believed that spontaneous emission (SE) necessary to remove entropy from an atomic sample during laser cooling. In fact, SE needed for energy removal when cooling done with single-frequency light, but more than one frequency, both and can be removed using only stimulated processes. Our experimental demonstration of this phenomenon works by restricting the atom–light interaction a time short compared cycle absorption followed natural decay [Phys. Rev. Lett.114, 043002...
A bright metastable helium (He∗) beam is collimated sequentially with the bichromatic force and three optical molasses velocity compression stages. Each He∗ atom in has 20 eV of internal energy that can destroy a molecular resist assembled on gold coated silicon wafer. Patterns are imprinted onto layer standard selective etch. Patterning wafer was demonstrated two methods. First, mesh used to protect parts making an array grid lines. Second, standing wave λ=1083 nm light channel focus atoms...
An X-ray free-electron laser oscillator (XFELO) is a new type of hard source that would produce fully coherent pulses with meV bandwidth and stable intensity. The XFELO complements existing sources based on self-amplified spontaneous emission (SASE) from high-gain lasers (XFEL) ultra-short broad-band chaotic spectra. This report discussions scientific opportunities enabled by an during workshop held at SLAC June 29 - July 1, 2016
The characterization of surfaces using photoelectron spectroscopy or photoemission electron microscopy provides sensitive probes surface structure and electronic properties. Conventional extreme ultraviolet (XUV) light sources used for do not have ultrafast time resolution, which inhibits applying these techniques to the study dynamics on their natural scale. high harmonics (HHG) intense femtosecond laser pulses are capable providing ultrashort XUV photoemission. However, pulse-based...
The bichromatic force allows laser cooling using stimulated processes only. We provide details of our simulations the when effects spontaneous emission are suppressed by restricting atom-light interaction time to be short enough that there cannot a significant number events. This requires simulation include dynamics atomic motion through light field is coupled internal state determine on atom. first tested with several standard optical configurations confirm its accuracy. Then results,...
The unique optical properties of graphene, with broadband absorption and ultrafast response, make it a critical component optoelectronic spintronic devices. Using time-resolved momentum microscopy high data rate dynamic range, we report momentum-space measurements electrons promoted to the graphene conduction band visible light, their subsequent relaxation. We observe pronounced non-thermal distribution nascent photoexcited lattice pseudospin polarization in remarkable agreement results...
We describe an instrument for high-repetition rate time-resolved XUV photo-electron spectroscopy, based on cavity-enhanced high-order harmonic generation. This system enables ultrafast surface photoemission studies without space-charge constraints.
Cavity enhanced high harmonic generation (HHG) can provide XUV pulses with repetition rate. In this summary, we present a Yb:fiber laser 55 W average output power, 150 fs pulse duration and 78 MHz rate ideal for driving cavity-enhanced HHG.
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text C. Allred, J. Reeves, Corder, and H. Metcalf, "Atomic Nanofabrication of Periodic Structures," in Conference Lasers Electro-Optics/International Quantum Electronics Conference, OSA Technical Digest (CD) (Optica Publishing Group, 2009), paper IPDA2. Export BibTex Endnote (RIS) HTML Plain alert Save article