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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02 Jun 1996
TL;DR: In this article, femtosecond time-resolved measurements of the longitudinal and radial structure of laser wakefield oscillations using an all-optical technique known as photon acceleration are presented.
Abstract: Summary form only given. Because the electrostatic fields present in plasma waves can exceed those achievable in conventional accelerators and approach atomic scale values, plasma-based accelerators have received considerable attention as compact sources of high-energy electron pulses. Optical probes such as stimulated Raman scattering or terahertz radiation at /spl omega//sub p/ have provided only spatially averaged indications of the wave's existence. However, the ability to measure plasma wave microstructure directly is important for addressing fundamental issues of wakefield generation and propagation. We report femtosecond time-resolved measurements of the longitudinal and radial structure of laser wakefield oscillations using an all optical technique known as photon acceleration.
131 citations
TL;DR: A compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported and can perform high speed 2D raster-scan imaging without scan rate dependent astigmatism is shown.
Abstract: We describe a high speed 3D Acousto-Optic Lens Microscope (AOLM) for femtosecond 2-photon imaging. By optimizing the design of the 4 AO Deflectors (AODs) and by deriving new control algorithms, we have developed a compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported. We show that the AOLM can perform high speed 2D raster-scan imaging (>150 Hz) without scan rate dependent astigmatism. It can deflect and focus a laser beam in a 3D random access sequence at 30 kHz and has an extended focusing range (>137 μm; 40X 0.8NA objective). These features are likely to make the AOLM a useful tool for studying fast physiological processes distributed in 3D space
131 citations
TL;DR: Grazing-incidence x-ray diffraction is employed to characterize the coherent, femtosecond laser-induced lattice motion of a bismuth crystal as a function of depth from the surface with a temporal resolution of 193+/-8 fs.
Abstract: We employ grazing-incidence femtosecond x-ray diffraction to characterize the coherent, femtosecond laser-induced lattice motion of a bismuth crystal as a function of depth from the surface with a temporal resolution of 193 +/- 8 fs. The data show direct consequences on the lattice motion from carrier diffusion and electron-hole interaction, allowing us to estimate an effective diffusion rate of D=2.3 +/- 0.3 cm(2)/s for the highly excited carriers and an electron-hole interaction time of 260 +/- 20 fs.
131 citations
TL;DR: In this paper, the development of parametric down-conversion devices operating in the mid-infrared, from 3μm to about 20μm, based on non-oxide nonlinear optical crystals is reviewed.
131 citations
TL;DR: In this article, the capabilities of metallic spintronic thin-film stacks as a source of intense and broadband terahertz electromagnetic fields were explored, and a femtosecond laser pulse was measured to have a duration of 230 fs, a peak field of 300 kV cm−1, and an energy of 5 nJ.
Abstract: We explore the capabilities of metallic spintronic thin-film stacks as a source of intense and broadband terahertz electromagnetic fields. For this purpose, we excite a W/CoFeB/Pt trilayer (thickness of 5.6 nm) on a large-area glass substrate (diameter of 7.5 cm) by a femtosecond laser pulse (energy 5.5 mJ, duration 40 fs, and wavelength 800 nm). After focusing, the emitted terahertz pulse is measured to have a duration of 230 fs, a peak field of 300 kV cm−1, and an energy of 5 nJ. In particular, the waveform exhibits a gapless spectrum extending from 1 to 10 THz at 10% of its amplitude maximum, thereby facilitating nonlinear control over matter in this difficult-to-reach frequency range on the sub-picosecond time scale.
130 citations