We report on the first experimental observation of dual wavelength domain wall type of dark solitons in a fiber laser made of all normal group velocity dispersion fibers. It was shown that this solitary wave is formed due to the cross coupling between two different wavelength laser beams and consists of localized dip structures separating the two different wavelength laser emissions.

A novel method for forming pure helical laser beams of pre-determined helicity is presented. It is mainly based on replacing one of the laser mirrors with a spiral phase element. The basic principles along with experimental results using a CO laser are described. q 2000 Elsevier Science B.V. All rights reserved. 2 PACS: 41.85.Ct; 41.85.Ew; 42.60.Jf; 42.60.Da

A nonlinear model of two-beam free-electron laser (FEL) in the absence of slippage is presented. The two beams are assumed to be cold with different energies and the fundamental resonance of the higher energy beam is at the third harmonic of lower energy beam. By using Maxwell’s equations and full Lorentz force equations of motion for the electron beams, coupled differential equations are deriv...

We have created a Bose-Einstein condensate (BEC) of 87Rb atoms directly in an optical trap. We employ a quasielectrostatic dipole force trap formed by two crossed CO2 laser beams. Loading directly from a sub-Doppler laser-cooled cloud of atoms results in initial phase space densities of approximately 1/200. Evaporatively cooling through the BEC transition is achieved by lowering the power in th...

A new method of Monte Carlo simulation has been developed to simulate the spatial distribution of photon density of converging laser beams propagating in a turbid medium such as the phantom of biological tissue. This method can be used to obtain steady-state light distribution in the tissue phantom for a continuous-wave laser beam. We have calculated the steady-state distribution of the photon ...

The concepts of laser-plasma based accelerator and injector are discussed here. Recent tests done at LOA as well as design studies of high-quality few GeV’s electron beam with low energy spread (1%) are presented. These laser-produced particle beams have a number of interesting properties and could lend themselves to applications in many fields, including medicine (radiotherapy), chemistry (rad...

Laser-driven, quasimonoenergetic electron beams of up to approximately 200 MeV in energy have been observed from steady-state-flow gas cells. These beams emitted within a low-divergence cone of 2.1+/-0.5 mrad FWHM display unprecedented shot-to-shot stability in energy (2.5% rms), pointing (1.4 mrad rms), and charge (16% rms) owing to a highly reproducible gas-density profile within the interact...

We show that focusing a laser light onto the boundary between antiparallel ferroelectric domains leads to the non-collinear generation of two second harmonic (SH) beams. The beams are emitted in a plane normal to the domain boundaries at the angles that satisfy the Cerenkov-type phase matching condition. Moreover, these beam disappear when the laser light is focused on a homogenous part of a si...

The spatial energy distributions of beams of protons accelerated by ultrahigh intensity (>10(19)Wcm2) picosecond laser pulse interactions with thin foil targets are investigated. Using separate, low intensity (<10(13)Wcm2) nanosecond laser pulses, focused onto the front surface of the target foil prior to the arrival of the high intensity pulse, it is demonstrated that the proton beam profile c...

We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a ...