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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the competition between femtosecond laser pulse induced optical breakdown and filamentation in condensed matter is studied both experimentally and numerically using water as an example, and the coexistence of filamentation and breakdown is observed under tight focusing conditions.
Abstract: The competition between femtosecond laser pulse induced optical breakdown and femtosecond laser pulse filamentation in condensed matter is studied both experimentally and numerically using water as an example. The coexistence of filamentation and breakdown is observed under tight focusing conditions. The development of the filamentation process from the creation of a single filament to the formation of many filaments at higher pulse energy is characterized systematically. In addition, strong deflection and modulation of the supercontinuum is observed. They manifest themselves at the beginning of the filamentation process, near the highly disordered plasma created by optical breakdown at the geometrical focus.

178 citations

Journal ArticleDOI
TL;DR: Femtosecond photon-echo experiments on sodium resorufin in dimethylsulfoxide at room temperature show that optical dephasing in solution is of non-Markovian character and the optical dynamics of this system appears to fall in the intermediate modulation regime.
Abstract: Femtosecond photon-echo experiments on sodium resorufin in dimethylsulfoxide at room temperature show that optical dephasing in solution is of non-Markovian character. A single Gauss-Markov stochastic modulation process is used to interpret both the femtosecond light-scattering results and the steady-state absorption spectrum. The optical dynamics of this system appears to fall in the intermediate modulation regime. No evidence was found for contributions of slower dynamical processes to the absorption line breadth.

178 citations

Journal ArticleDOI
TL;DR: In this article, the authors review the frequency-domain description of a mode-locked laser and the connection between the carrier-envelope phase and the frequency spectrum to provide a basis for understanding how the absolute frequencies can be determined and controlled.
Abstract: The merging of continuous wave laser-based precision optical-frequency metrology with mode-locked ultrafast lasers has led to precision control of the visible and near-infrared frequency spectrum produced by mode-locked lasers. Such a phase-controlled mode-locked laser forms the foundation of a "femtosecond optical-frequency comb generator" with a regular comb of sharp lines with well-defined frequencies. For a comb with sufficiently broad bandwidth, it is now straightforward to determine the absolute frequencies of all of the comb lines. This ability has revolutionized optical-frequency metrology, synthesis, and optical atomic clocks. Precision femtosecond optical-frequency combs also have a major impact on time-domain applications, including carrier-envelope phase stabilization, synthesis of a single pulse from two independent lasers, nonlinear spectroscopy, and passive amplifiers based on empty external optical cavities. The authors first review the frequency-domain description of a mode-locked laser and the connection between the carrier-envelope phase and the frequency spectrum to provide a basis for understanding how the absolute frequencies can be determined and controlled. Using this understanding, applications in optical-frequency metrology and synthesis and optical atomic clocks are discussed. This is followed by discussions of time-domain experiments.

177 citations

Journal ArticleDOI
TL;DR: It is found that the dynamics of the ultrafast carrier dynamics in single-walled carbon nanotubes are dependent on excitation intensity and the electronic transitions initially excited.
Abstract: Ultrafast carrier dynamics in individual semiconducting single-walled carbon nanotubes was studied by femtosecond transient absorption and fluorescence measurements. After photoexcitation of the second van Hove singularity of a specific tube structure, the relaxation of electrons and holes to the fundamental band edge occurs to within 100 fs. The fluorescence decay from this band is dependent on the excitation density and can be rationalized by exciton annihilation theory. In contrast to fluorescence, the transient absorption has a distinctly different time and intensity dependence for different tube structures, suggesting a branching to emissive and trap states following photoexcitation.

177 citations

Journal ArticleDOI
TL;DR: In this article, the physics governing the laser cluster interaction is fundamentally different than in previous studies, and there has been much activity in extending these studies to very high intensity, ultrashort laser pulses with peak laser intensities >1015 Wcm −2 and pulse widths of 0.1 to 10 ps.
Abstract: Atomic clusters have long been studied by chemists and physicists because of the unique position that clusters hold as an intermediate state between molecules and solids [1]. Many studies have traced the properties of materials from their monatomic characteristics to their bulk state characteristics through an examination of the material as it forms larger and larger clusters. Recently, there has been much activity in extending these studies to very high intensity, ultrashort laser pulses with peak laser intensities >1015 Wcm −2 and pulse widths of 0.1 to 10 ps [2–11]. There has also been some preliminary theoretical work in this area as well [6,12]. In this parameter regime the physics governing the laser cluster interaction is fundamentally different than in previous studies. At these intensities the laser interaction is non-perturbative and very high order multiphoton ionization and strong electric field tunnel ionization are possible. Consequently, highly charged ions can be produced [2,5,8,10]. Furthermore, the short pulses used are comparable to or shorter than the disassembly times of a cluster in the laser field [6] and, so, the entire laser pulse interacts with an inertially confined body of atoms.

177 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,403
20223,116
20211,239
20201,571
20191,715
20181,651