Topic
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.
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TL;DR: Time-resolved measurements of X-ray free-electron lasers are reported by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source to demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron andX-ray temporal characterization.
Abstract: Characterizing femtosecond X-ray pulses that vary from shot to shot is important for data interpretation. Here, Behrens et al. measure time-resolved lasing effects on the electron beam and extract the temporal profile of X-ray pulses using an X-band radiofrequency transverse deflector.
227 citations
TL;DR: Compared to the conventional femtosecond two-photon fabrication, this work provides an alternative, effective and cheap processing method for the fabrication of micro optic device that requires arbitrary shape with high surface quality and small scale.
Abstract: We report the fabrication of micro lens using an alternative annular scanning mode with continuous variable layer thickness by two-photon polymerization after multi-parameter optimization. Laser scanning mode and scanning pace parameter are optimized to achieve good appearance. As examples of the results, a 2 × 2 micro spherical lens array with diameter of 15 μm and a micro Fresnel lens with diameter of 17 μm are fabricated. Their optical performances are also tested. Compared to the conventional femtosecond two-photon fabrication, this work provides an alternative, effective and cheap processing method for the fabrication of micro optic device that requires arbitrary shape with high surface quality and small scale.
227 citations
TL;DR: The use of a bulk-structured Bi(2)Te(3) topological insulator (TI) as an ultrafast mode-locker to generate femtosecond pulses from an all-fiberized cavity indicates that high-crystalline-quality atomic-layered films of TI, which demand complicated and expensive material processing facilities, are not essential for ultrafast laser mode-locking applications.
Abstract: We experimentally demonstrate the use of a bulk-structured Bi2Te3 topological insulator (TI) as an ultrafast mode-locker to generate femtosecond pulses from an all-fiberized cavity. Using a saturable absorber based on a mechanically exfoliated layer about 15 μm thick deposited onto a side-polished fiber, we show that stable soliton pulses with a temporal width of ~600 fs can readily be produced at 1547 nm from an erbium fiber ring cavity. Unlike previous TI-based mode-locked laser demonstrations, in which high-quality nanosheet-based TIs were used for saturable absorption, we chose to use a bulk-structured Bi2Te3 layer because it is easy to fabricate. We found that the bulk-structured Bi2Te3 layer can readily provide sufficient nonlinear saturable absorption for femtosecond mode-locking even if its modulation depth of ~15.7% is much lower than previously demonstrated nanosheet-structured TI-based saturable absorbers. This experimental demonstration indicates that high-crystalline-quality atomic-layered films of TI, which demand complicated and expensive material processing facilities, are not essential for ultrafast laser mode-locking applications.
227 citations
TL;DR: It is demonstrated that the ablation process involves three different mechanisms as a function of deposited energy, which can result from mechanical fragmentation, which does not require the system to cross any metastability or instability line.
Abstract: We study the basic mechanisms leading to ablation by femtosecond laser pulses using molecular dynamics and a simple two-dimensional Lennard-Jones model. We demonstrate that the ablation process involves three different mechanisms as a function of deposited energy. In particular, it can result from mechanical fragmentation, which does not require the system to cross any metastability or instability line. The relevance of homogeneous nucleation and vaporization for the description of ablation in this regime is also established.
226 citations
01 Jan 2011
TL;DR: It is demonstrated the compression of 95 keV, space-charge-dominated electron bunches to sub-100 fs durations and the bunches have sufficient charge and are of sufficient quality to capture a diffraction pattern with a single shot, which is demonstrated by a Diffraction experiment on a polycrystalline gold foil.
Abstract: We demonstrate the compression of 95 keV, space-charge-dominated electron bunches to sub-100 fs durations. These bunches have sufficient charge (200 fC) and are of sufficient quality to capture a diffraction pattern with a single shot, which we demonstrate by a diffraction experiment on a polycrystalline gold foil. Compression is realized by means of velocity bunching by inverting the positive space-charge-induced velocity chirp. This inversion is induced by the oscillatory longitudinal electric field of a 3 GHz radio-frequency cavity. The arrival time jitter is measured to be 80 fs.
226 citations