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: In this paper, the propagation of electromagnetic pulses in naturally occurring dielectric surface layers has been examined and analog recordings of wide-angle reflection and refraction profiles were taken and recorded in a continuous graphic display.
Abstract: The propagation of electromagnetic pulses in naturally occurring dielectric surface layers has been examined. Pulse duration used in field experiments reported here has been on the order of nanoseconds with pulse bandwidths in the high VHF to low UHF band. The layers were sheets of fresh water ice and granite at thicknesses ranging between .4 and 4 m. Both transverse electric (TE) and transverse magnetic (TM) modes were attempted but only the TE propagation could be interpreted. Analog recordings of wide-angle reflection and refraction (WARR) profiles were taken and recorded in a continuous graphic display. The displays allowed easy identification of phase fronts thereby facilitating study of of the dispersion of the pulses. The phase and group velocities of the wave-group packets agree well with the velocities predicted from dispersion curves derived from the modal waveguide equation. In one case the Airy phase of wave-packet propagation occurred. The best measure of the dielectric constant of the layer was the frequency of the air wave.
72 citations
TL;DR: In this paper, a nano-scale photo-electron source was proposed for ultrashort pulse durations and well-suited for time-resolved diffraction and advanced laser acceleration experiments.
Abstract: We present a nano-scale photoelectron source, optimized for ultrashort pulse durations and well-suited for time-resolved diffraction and advanced laser acceleration experiments. A tungsten tip of several-ten-nanometers diameter mounted in a suppressor-extractor electrode configuration allows the generation of 30 keV electron pulses with an estimated pulse duration of 9 fs (standard deviation; 21 fs full width at half maximum) at the gun exit. We infer the pulse duration from particle tracking simulations, which are in excellent agreement with experimental measurements of the electron-optical properties of the source in the spatial domain. We also demonstrate femtosecond-laser triggered operation of the apparatus. The temporal broadening of the pulse upon propagation to a diffraction sample can be greatly reduced by collimating the beam. Besides the short electron pulse duration, a tip-based source is expected to feature a large transverse coherence and a nanometric emittance.
72 citations
TL;DR: The lateral and vertical dimensions of the liquid meniscus are in the 5-30 nm range as mentioned in this paper, and the size depends on the duration and strength of the voltage pulse.
Abstract: We have studied the dimensions of water capillaries formed by an applied electrical field between an atomic force microscope tip and a flat silicon surface. The lateral and vertical dimensions of the liquid meniscus are in the 5–30 nm range. The size depends on the duration and strength of the voltage pulse. It increases by increasing the voltage strength or the pulse duration. The meniscus size is deduced from the experimental measurement of the snap-off separation. These results are of special relevance to optimize local oxidation nanolithography.
72 citations
TL;DR: An ultrafast fiber-chirped-pulse amplification system using a combination of spatial and temporal coherent pulse combination is presented, achieving the highest energy achieved by an ultrafast Fiber-based laser system to date.
Abstract: An ultrafast fiber-chirped-pulse amplification system using a combination of spatial and temporal coherent pulse combination is presented. By distributing the amplification among eight amplifier channels and four pulse replicas, up to 12 mJ pulse energy with 700 W average power and 262 fs pulse duration have been obtained with a system efficiency of 78% and excellent beam quality. To the best of our knowledge, this is the highest energy achieved by an ultrafast fiber-based laser system to date.
72 citations
TL;DR: By use of a laser diode as a pump source, a self-Q-switched laser from a Cr, Nd:YAG crystal is demonstrated, where the pulse width remains constant while the pulse repetition rate varies with pump power.
Abstract: By use of a laser diode as a pump source, a self-Q-switched laser from a Cr,Nd:YAG crystal is demonstrated. The output Q–switched traces are very stable, the threshold pump power is 3.5 W, the pulse duration is 50 ns, and the slope efficiency is as high as 20%. In addition, the pulse width remains constant while the pulse repetition rate varies with pump power.
72 citations