Topic
Femtosecond
About: Femtosecond is a research topic. Over the lifetime, 35106 publications have been published within this topic receiving 691405 citations. The topic is also known as: 1 E-15 s & fs.
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TL;DR: In this paper, the propagation of the photoelectron cloud to the detector is studied with a full $N$-body numerical simulation and the influence of various parameters, in particular number of electrons per pulse, source size, pulse duration, kinetic energy and emission-angle distributions as well as presence of mirror charges in the sample, is investigated in detail.
Abstract: Solid-state photoemission spectroscopy relies to a large part on pulsed photon sources: third-generation synchrotron-radiation sources and ultrafast laser systems in particular. Especially when the photon pulses are intense, Coulombic repulsion between the emitted electrons will be a limiting factor for photoemission experiments aiming at highest energy and angle resolutions. In the present work, the propagation of the photoelectron cloud to the detector is studied with a full $N$-body numerical simulation. The influence of various parameters, in particular number of electrons per pulse, source size, pulse duration, kinetic-energy and emission-angle distributions as well as presence of mirror charges in the sample, is investigated in detail. Previous experimental results obtained with various picosecond and femtosecond light sources are successfully reproduced and the general resolution limits of solid-state photoemission using pulsed photon sources are explored. The results are potentially important for the design and interpretation of photoemission experiments with next-generation light sources, such as free-electron lasers and high-harmonic generation sources.
134 citations
TL;DR: Screening results from cryocooled crystals of β2-adrenoreceptor and an RNA polymerase II complex indicate the potential to extend the diffraction resolution obtainable from very radiation-sensitive samples beyond that possible with undulator-based synchrotron sources.
Abstract: The emerging method of femtosecond crystallography (FX) may extend the diffraction resolution accessible from small radiation-sensitive crystals and provides a means to determine catalytically accurate structures of acutely radiation-sensitive metalloenzymes. Automated goniometer-based instrumentation developed for use at the Linac Coherent Light Source enabled efficient and flexible FX experiments to be performed on a variety of sample types. In the case of rod-shaped Cpl hydrogenase crystals, only five crystals and about 30 min of beam time were used to obtain the 125 still diffraction patterns used to produce a 1.6-A resolution electron density map. For smaller crystals, high-density grids were used to increase sample throughput; 930 myoglobin crystals mounted at random orientation inside 32 grids were exposed, demonstrating the utility of this approach. Screening results from cryocooled crystals of β2-adrenoreceptor and an RNA polymerase II complex indicate the potential to extend the diffraction resolution obtainable from very radiation-sensitive samples beyond that possible with undulator-based synchrotron sources.
134 citations
TL;DR: In this article, the authors demonstrate high-field (>8 MV/cm) terahertz generation at a high-repetition-rate (1 kHz) via two-color laser filamentation.
Abstract: We demonstrate high-field (>8 MV/cm) terahertz generation at a high-repetition-rate (1 kHz) via two-color laser filamentation. Here, we use a cryogenically cooled femtosecond laser amplifier capable of producing 30 fs, 15 mJ pulses at 1 kHz as a driver, along with a combination of a thin dual-wavelength half-waveplate and a Brewster-angled silicon window to enhance terahertz generation and transmission. We also introduce a cost-effective, uncooled microbolometer camera for real-time terahertz beam profiling with two different modes.
134 citations
TL;DR: The ability of the Airy waveform to regenerate its dominant intensity peak results in the generation of distinct spectral features in a highly nonlinear optical fiber.
Abstract: We report experiments and numerical simulations on supercontinuum generation with femtosecond Airy pulses in a highly nonlinear optical fiber. The ability of the Airy waveform to regenerate its dominant intensity peak results in the generation of distinct spectral features. Airy pulses and other self-healing temporal waveforms may be useful for the generation of spectra with desired properties.
134 citations
TL;DR: A near-diffraction-limited transform-limited multiterawatt laser system that produces approximately 30-fs 125-mJ 800-nm pulses at a repetition rate of 10 Hz has been constructed.
Abstract: A near-diffraction-limited transform-limited multiterawatt laser system that produces approximately 30-fs 125-mJ 800-nm pulses at a repetition rate of 10 Hz has been constructed. Methods for the control of femtosecond time-scale phase and amplitude distortions have been developed and implemented.
134 citations