Pulse duration

About: Pulse duration is a research topic. Over the lifetime, 19429 publications have been published within this topic receiving 286507 citations.

Laser based synchrotron radiation

Abstract: Beams of x rays in the kiloelectronvolt energy range have been produced from laser-matter interaction. Here, energetic electrons are accelerated by a laser wakefield, and experience betatron oscillations in an ion channel formed in the wake of the intense femtosecond laser pulse. Experiments using a 50 TW laser (30 fs duration) are described, as well as comparisons with numerical simulations. These results pave the way of a new generation of radiation in the x-ray spectral range, with a high collimation and an ultrafast pulse duration, produced by the use of compact laser system.

Precession interpretation of the isolated pulsar psr b1828-11

Abstract: Pulse timing of the isolated pulsar PSR B1828-11 shows strong Fourier power at periods 1000, 500, and 250 days, correlated with changes in the pulse profile (Stairs, Lyne, & Shemar). We study the extent to which these data can be explained by precession of the star's rigid crust coupled to the magnetic dipole torque. We find that the correlated changes in the pulse duration and spin period derivative can be explained as precession at a period of 500 days with a wobble angle of 3° if the star's dipole moment is nearly orthogonal to its symmetry axis. The dipole torque produces a harmonic at ~250 days. Comparison of the predicted spin dynamics with the observed pulse durations requires the radio beam to have a nonstandard "hourglass" shape. We make predictions of variations in beam polarization and pulse profile with which to test this interpretation. The precession interpretation of PSR B1828-11 seriously challenges the current understanding of the liquid interior of the neutron star. In particular, if the internal liquid is in a superfluid state, its rotational vortices cannot be significantly pinned to the crust.

Terahertz generation via optical rectification of x-mode laser in a rippled density magnetized plasma

Abstract: A scheme of resonant terahertz radiation generation by the optical rectification of a picosecond laser pulse in rippled density magnetized plasma is examined. The x-mode laser pulse, propagating perpendicular to dc magnetic field, exerts a quasistatic ponderomotive force on electrons, imparting them a drift with finite transverse component. The drift velocity beats with the density ripple to produce a current, resonantly driving terahertz radiation at frequency comparable to the inverse pulse duration. The terahertz power scales as the square of density ripple amplitude and rises with magnetic field strength. In the case when magnetic field is azimuthal with appropriate r-dependence, the terahertz power has a ring shape intensity distribution. At laser intensity of ∼3×1015 W/cm2, in a 0.01% critical density plasma with 30 kG magnetic field and 30% density ripple, one may have power conversion efficiency of 0.04%.

Femtosecond Yb:CaGdAlO4 thin-disk oscillator.

Abstract: A mode-locked thin-disk laser based on Yb:CALGO is demonstrated for the first time. At an average output power of 28 W we obtained pulses with a duration of 300 fs and a pulse energy of 1.3 μJ. 197 fs pulses with 0.9 μJ of energy were achieved at an average output power of 20 W. The shortest pulse duration measured in our experiments was 135 fs with a spectrum centered at 1043 nm. The experiments also revealed a very broad tunability from 1032 to 1046 nm with sub-200 fs pulses.