Topic
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: The results demonstrated that the microfiber-based TI PLD film SA is a promising device for practical multi-GHz ultrashort pulses generation and proposed a newly explanation for the impact of nonlinear effect of SA on the harmonic mode-locking behavior.
Abstract: By utilizing the pulsed laser deposition (PLD) method, we fabricated a kind of microfiber-based topological insulator (TI) saturable absorber (SA) which has inherent merits of effective and robust properties. We also proposed a newly explanation for the impact of nonlinear effect of SA on the harmonic mode-locking (HML) behavior. Upon employing on the SA, we achieved stable fundamental mode-locking (FML) at central wavelength of 1562.4 nm with pulse duration as short as 320 fs. By adjusting the intracavity polarization state at maximum pump power of 395 mW, we obtained stable femtosecond harmonic soliton pulse generation with repetition rate of 2.95 GHz and output power of 45.3 mW. Our results demonstrated that the microfiber-based TI PLD film SA is a promising device for practical multi-GHz ultrashort pulses generation.
132 citations
TL;DR: To evaluate the error in T1 estimates using inversion‐recovery‐based T1 mapping due to imperfect inversion and to perform a systematic study of adiabatic inversion pulse designs in order to maximize inversion efficiency for values of transverse relaxation in the myocardium subject to a peak power constraint.
Abstract: Purpose
To evaluate the error in T1 estimates using inversion-recovery-based T1 mapping due to imperfect inversion and to perform a systematic study of adiabatic inversion pulse designs in order to maximize inversion efficiency for values of transverse relaxation (T2) in the myocardium subject to a peak power constraint.
Methods
The inversion factor for hyperbolic secant and tangent/hyperbolic tangent adiabatic full passage waveforms was calculated using Bloch equations. A brute-force search was conducted for design parameters: pulse duration, frequency range, shape parameters, and peak amplitude. A design was selected that maximized the inversion factor over a specified range of amplitude and off-resonance and validated using phantom measurements. Empirical correction for imperfect inversion was performed.
Results
The tangent/hyperbolic tangent adiabatic pulse was found to outperform hyperbolic secant designs and achieve an inversion factor of 0.96 within ±150 Hz over 25% amplitude range with 14.7 µT peak amplitude. T1 mapping errors of the selected design due to imperfect inversion was ∼4% and could be corrected to <1%.
Conclusions
Nonideal inversion leads to significant errors in inversion-recovery-based T1 mapping. The inversion efficiency of adiabatic pulses is sensitive to transverse relaxation. The tangent/hyperbolic tangent design achieved the best performance subject to the peak amplitude constraint. Magn Reson Med 71:1428–1434, 2014. © 2013 Wiley Periodicals, Inc.
132 citations
TL;DR: The model describes well the transmembrane transport caused by electropermeabilization, allowing to study the uptake of molecules as a function of elapsed time, voltage and pulse duration, and shows that the shapes of the curves of cell permeabilization and survival as functions of pulse amplitude can to a large extent be explained by cell size distribution.
132 citations
TL;DR: In this article, the authors investigated the ultrafast laser ablation of silicon and determined the thresholds of melting and ablation for two different pulse durations τ = 20 and 500fs.
132 citations
TL;DR: In this article, the application of ultrashort voltage pulses to a tiny tool electrode under suitable electrochemical conditions enables precise three-dimensional machining of stainless steel in order to reach submicrometer precision and high processing speed.
Abstract: Application of ultrashort voltage pulses to a tiny tool electrode under suitable electrochemical conditions enables precise three-dimensional machining of stainless steel In order to reach submicrometer precision and high processing speed, the formation of a passive layer on the workpiece surface during the machining process has to be prevented by proper choice of the electrolyte Mixtures of concentrated hydrofluoric and hydrochloric acid are well suited in this respect and allow the automated machining of complicated three-dimensional microelements The dependence of the machining precision on pulse duration and pulse amplitude was investigated in detail
132 citations