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Pulse duration

About: Pulse duration is a research topic. Over the lifetime, 19429 publications have been published within this topic receiving 286507 citations.


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TL;DR: O'Shea et al. as discussed by the authors showed that a much higher current density may be drawn from a short pulse or limited emitter area than is anticipated by the Child-Langmuir limiting current, which leads a distinction between a limiting current density and a current density critical for virtual cathode formation.
Abstract: Recent experiments at the University of Maryland using photoemission from a dispenser cathode have yielded some interesting results regarding the effects of the area of emission and of the ratio between the pulse length and the gap transit time on the amount of current that may be drawn from an electron gun before a virtual cathode forms. The experiments show that a much higher current density may be drawn from a short pulse or limited emitter area than is anticipated by the Child–Langmuir limiting current. There is also evidence that the current may be increased even after virtual cathode formation, which leads a distinction between a limiting current density and a current density critical for virtual cathode formation. The experiments have also yielded some interesting results on the longitudinal structure of the current pulse passed through the anode. Some empirical and theoretical scaling laws regarding the formation of virtual cathodes in an electron gun will be presented. This work was motivated by the needs of the University of Maryland Electron Ring (UMER) [P. G. O’Shea, M. Reiser, R. A. Kishek et al., Nucl. Instrum. Methods Phys. Res. A 464, 646 (2001)] where the goal is to generate pulses that are well-localized in time and space.

111 citations

Journal ArticleDOI
TL;DR: Efficient diode-pumped passively Q-switched Er:Lu2O3 laser operation at 2.84 μm was realized and a few-layer MoS2 nanosheet film was fabricated and employed as saturable absorber (SA) in a short plane-plane cavity.
Abstract: Efficient diode-pumped passively Q-switched Er:Lu2O3 laser operation at 2.84 μm was realized. A few-layer MoS2 nanosheet film on a YAG substrate, was fabricated and employed as saturable absorber (SA) in a short plane-plane cavity. Under an absorbed diode laser pump power of 7.61 W, an average output power of 1.03 W was generated with a pulse duration of 335 ns and a repetition rate of 121 kHz, resulting in a pulse energy of 8.5 μJ.

111 citations

Journal ArticleDOI
Kyung Taec Kim1, Chul Min Kim1, Moon-Gu Baik, G. Umesh1, Chang Hee Nam1 
TL;DR: In this paper, a method for obtaining a single sub-50-attosecond pulse using harmonic radiation is proposed, where the chirped structure of the harmonic radiation imposes a limit on the minimum achievable pulse duration, but its positive chirp can be compensated by the negative group delay dispersion of an appropriately selected x-ray filter material, used also for the spectral selection.
Abstract: A method for obtaining a single sub-50-attosecond pulse using harmonic radiation is proposed. For the generation of broad harmonic radiation during a single half-optical cycle, atoms are driven by a femtosecond laser pulse with intensity above the saturation intensity for optical field ionization and hence experience a large nonadiabatic increase of the laser electric field between optical cycles. Although the chirped structure of the harmonic radiation imposes a limit on the minimum achievable pulse duration, we demonstrate that its positive chirp can be compensated by the negative group delay dispersion of an appropriately selected x-ray filter material, used also for the spectral selection, resulting in a single attosecond pulse with a duration less than 50 as.

110 citations

Proceedings ArticleDOI
27 Aug 2003
TL;DR: In this article, the authors studied the ablation of metal targets in air with femtosecond laser pulses, and showed that the intensity of the laser pulses depends logarithmically on the optical penetration depth.
Abstract: In the current work ablation of metal targets in air with femtosecond laser pulses is studied. The laser pulses used for the study were 775 nm in wavelength, 150 fs in pulse duration and the repetition rate was 100 Hz. Ablation thresholds have been measured for a number of metals including stainless steel niobium, titanium and copper. The ablation depth per pulse was measured for laser pulse fluences ranging from the ablation threshold (of most metals) ~ 0.1 J/cm 2 up to 10 J/cm 2 . It has been shown previously that there are two different ablation regimes. In both cases the ablation depth per pulse depends logarithmically on the laser fluence. While operating in the first ablation regime the ablation rate is low and is dependant on the optical penetration depth, α -1 . While in the second ablation regime the ablation rate is greater and is characterized by the 'electron heat diffusion length' or the 'effective heat penetration depth'. In the present study good qualitative agreement in the ablation curve trends was observed with the data of other authors, e.g. Nolte et al (1997).

110 citations

Journal ArticleDOI
TL;DR: In this paper, a time-dependent quantum calculation of the scattering of a few-photon pulse on a single atom is presented, where the photon wave packet is assumed to propagate in a transversely strongly confined geometry, which ensures strong atom-light coupling and allows a quasi-one-dimensional treatment.
Abstract: We present a time-dependent quantum calculation of the scattering of a few-photon pulse on a single atom. The photon wave packet is assumed to propagate in a transversely strongly confined geometry, which ensures strong atom-light coupling and allows a quasi-one-dimensional treatment. The amplitude and phase of the transmitted, reflected, and transversely scattered part of the wave packet strongly depend on the pulse length (bandwidth) and energy. For a transverse mode size of the order of ${\ensuremath{\lambda}}^{2},$ we find nonlinear behavior for a few photons already, or even for a single photon. In a second step we study the collision of two such wave packets at the atomic site and find striking differences between the Fock state and coherent state wave packets of the same photon number.

110 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023175
2022408
2021543
2020619
2019668
2018665