The design of grating-based instruments to handle and condition coherent ultrafast pulses in the extreme-ultraviolet is discussed. The main application of such instruments is the monochromatization of high-order laser harmonics and free-electron-laser pulses in the femtosecond time scale. Broad-band monochromators require the use of diffraction gratings at grazing incidence. A grating can be us...

near-fault ground motions with long-period pulses can place severe demands on structures near an active fault. these pulse-type ground motions can be represented by pulse sequences with simple shapes. half-sinusoidal pulse sequences are used to approximate recorded ground motions and dynamic responses of sdof system under the excitation of these pulse sequences are studied. four cases are consi...

Lithium containing droplet and cluster targets irradiated by laser pulses are proposed as prospective source of for soft x-ray lithography. Analytical model and simulations show that laser with repetition rate of several MHz with energy of several mJ and pulse duration 10 ps is required.

We show that according to the GRB internal shock model the pulse duration and the interval between neighboring pulses are correlated and have a similar distribution. We analyze a sample of bright long bursts and find that the pulses duration have a lognormal distribution while the intervals has an excess of long intervals (relative to lognormal distribution). This excess can be explained by the...

Based on the free precession model of the isolated pulsar PSR B1828-11, Link & Epstein (2001) showed that the observed pulse durations require the radio beam to have a non-standard shape: the beam duration is larger for beam sweeps farthest from the dipole axis. In their analysis they assumed that the actual precession period is ≃ 500 d. Recent theoretical studies suggested that the actual prec...

Laser milling provides a new method of producing components for the micro tool manufacturing industry. This paper considers the technical capabilities of laser milling when applied to the machining of components for micro tooling. Characteristics important for laser milling as a micro tooling manufacturing process are reviewed. These characteristics are surface finish, aspect ratio, dimensional...

For focused pulses of light in isotropic nonlinear media, third-harmonic generation can be strongly affected by group-velocity mismatch between the fundamental and third-harmonic. There is a characteristic time determined by the group-velocity mismatch and the Rayleigh range of the focused pulse. The dynamics depend on two dimensionless quantities, namely the ratio of the characteristic time to...

We efficiently extract an ultraviolet femtosecond pulse train of milliwatt average power and 100 MHz repetition rate from a colliding pulse mode-locked dye laser by intracavity frequency doubling in KDP. The ultraviolet and visible outputs, which are comparable in power and pulse duration, are perfect synchronized with each

The challenge in visualizing fast microscale fluid motion phenomena is to record high-quality images free of motion-blur. Here, we present an illumination technique based on laser-induced fluorescence which delivers high-intensity light pulses of 7 ns. The light source consists of a Q-switched Nd:YAG laser and a laser dye solution incorporated into a total internal reflection lens, resulting in...

This paper introduces and discusses the main aspects of multicolored femtosecond pulse generation using cascaded four-wave mixing (CFWM) in transparent bulk materials. Theoretical analysis and semi-quantitative calculations, based on the phase-matching condition of the four-wave mixing process, explain the phenomena well. Experimental studies, based on our experiments, have shown the main chara...