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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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Journal ArticleDOI
TL;DR: A novel scheme to compress the radiation pulse in x-ray free electron lasers is proposed not only to shorten the pulse length but also to enhance the peak power of the radiation, by inducing a periodic current enhancement with an optical laser and applying a temporal shift between the optical and electron beams.
Abstract: A novel scheme to compress the radiation pulse in x-ray free electron lasers is proposed not only to shorten the pulse length but also to enhance the peak power of the radiation, by inducing a periodic current enhancement with an optical laser and applying a temporal shift between the optical and electron beams. Calculations show that a 10-keV x-ray pulse with a peak power of 5 TW and a pulse length of 50 asec can be generated by applying this scheme to an existing x-ray free electron laser facility.

77 citations

Journal ArticleDOI
TL;DR: In this paper, Stokes et al. demonstrated quasi continuous-wave (qCW) yellow emission (pulse duration 5 ms, repetition rate 20 Hz) at 559 nm through intracavity sum frequency generation (SFG) of Stokes and fundamental fields in Nd:YVO4 diode pumped self-Raman laser for the first time.
Abstract: Quasi continuous-wave (qCW) yellow emission (pulse duration 5 ms, repetition rate 20 Hz) at 559 nm is demonstrated through intracavity sum frequency generation (SFG) of Stokes and fundamental fields in Nd:YVO4 diode pumped self-Raman laser for the first time. Average in pulse output power at 559 nm was 0.47 W for 22 W of pump power, which corresponds to 2.1% of diode-to-yellow efficiency. The pulsed mode of operation was due to diode pump modulation and was used to reduce thermal stress of the crystal.

77 citations

Journal ArticleDOI
TL;DR: In this paper, a phenomenological model of sub-picosecond pulse evolution in semiconductor laser amplifiers, which includes carrier heating effect, gain dispersion, gain saturation, and three kinds of self-phase modulations, is presented.
Abstract: We present a phenomenological model of subpicosecond pulse evolution in semiconductor laser amplifiers, which includes carrier heating effect, gain dispersion, gain saturation, and three kinds of self-phase modulations (SPM). The results obtained from this model are applied to and found to agree very well with experimental measurements of spectral distortions and time-resolved gain on a semiconductor laser amplifier with 460-fs and 2-ps input pulses. The device parameters that are used to match the experimental results are within a reasonable range, either suggested by previous experiments or by published calculations, The results show that the evolution of the pulses and their spectra is sensitively dependent on the input pulse shape and on a variety of time domain and frequency domain amplitude and phase shaping effects. Matching the theory to the experimental data suggests that among the possible causes of the carrier heating two-photon absorption (TPA) is the most important. This effect of TPA needs to be included to properly account for the observed dependence of the carrier heating gain reduction on the pulse length. By examining separately the contribution of the corresponding terms, we also prove the importance of SPM due to the carrier heating and to the instantaneous nonlinear index in shaping the output spectrum. We compare our model with Agrawal's theory, which is valid for pulses of tens of picosecond duration, and find large differences for subpicosecond pulses. For 2-ps pulses, on the other hand, the differences are fewer and less dramatic. The good agreement of the new model with experiments will now allow diagnostics and predictions of pulse evolution in semiconductor optical amplifiers from the picosecond to the subpicosecond range. >

77 citations

Journal ArticleDOI
TL;DR: In this article, an electrothermal mechanism of switching has been used to explain the pulse repetition frequency dependence of the delay time, td, in amorphous silicon films produced by electron-beam evaporation in a Ti-Si-Ti sandwich structure.
Abstract: The pulse repetition frequency dependence of the delay time, td, in amorphous silicon films produced by electron‐beam evaporation in a Ti–Si–Ti sandwich structure has been found to give two opposite trends. Below about 1 kHz, td increases as the frequency is increased but is independent of the pulse duration. Above 1 kHz, td decreases with frequency and is also reduced in magnitude by increasing the pulse width. In this paper, an electrothermal mechanism of switching has been used to explain the above phenomenon satisfactorily. The predictions of the model as regards td decreasing with increasing over‐voltage and increasing film thickness, the threshold voltage exhibiting a half‐power law relationship with thickness and its temperature dependence, and the effect of space–charge injection around the electrodes are confirmed by experiments. Finally, a view of switching combining both thermal and electronic elements is presented.

77 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the pulsed photoacoustic (PA) technique to study the synthesis by laser ablation of silver nanoparticles (Ag-NPs) in ethanol.

77 citations


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