Laser beam welding is becoming widely used in many industrial applications. This paper reviews recent research conducted on the performance, potential and problems of thick section butt joint laser welding. Common defects that occur in laser beam welding with high power laser welding are discussed and possible solutions proposed. Methods of welding process efficiency improvement are analyzed.

Fraunhofer Institute for Laser Technology had developed the SHADOW welding technique, in which high speed joining with minimal distortion is possible using a pulsed Nd:YAG laser. The possibility of high speed, high quality welding had been also reported by use of a single-mode fiber laser. The combination of micro-beam and high speed laser scanning offers potential advantages for thin metal she...

Laser-based missile-defence systems are being increasingly employed on aircraft to provide protection when attacked by optically-guided weapons. In some engagements the laser beam must pass through the exhaust gases of the aircraft. To predict the increase in laser beam divergence and jitter of the laser beam direction, an understanding of the exhaust gas structure and its influence is required...

A new mechanism is reported that increases electron energy gain from a laser beam of ultrarelativistic intensity in underdense plasma. The increase occurs when the laser produces an ion channel that confines accelerated electrons. The frequency of electron oscillations across the channel is strongly modulated by the laser beam, which causes parametric amplification of the oscillations and enhan...

Experimental laser beam profiles often deviate somewhat from the ideal Gaussian shape of the TEM(00) laser mode. In order to take these deviations into account when calculating light scattering, we propose a method for approximating the beam shape coefficients in the partial wave expansion of an experimental laser beam. We then compute scattering by a single dielectric spherical particle placed...

It is well known that atmospheric turbulence can severely degrade performance of various optical systems including the laser beam projection systems discussed here. These systems are designed to create and maintain a laser spot of the smallest possible size on a remotely located object in the atmosphere. Compensation (mitigation) of turbulence effects in the laser beam projection systems is typ...

We observed 8 10 7 . 1 × X-ray photons/pulse generated through relativistic Thomson scattering between the 14GW CO2 laser and 60MeV electron beam at Brookhaven National Laboratory. Non-linear Thomson scattering can be observed by upgrading peak power density of the CO2 laser. Introduction Development of high-intensity, short-pulse, and compact X-ray sources is demanded for various fields of sci...

PURPOSE Customized laser surgery attempts to correct higher order aberrations, as well as defocus and astigmatism. The success of such a procedure depends on using a laser beam that is small enough to produce fine ablation profiles needed to correct higher order aberrations. METHODS Wave aberrations were obtained from a population of 109 normal eyes and 4 keratoconic eyes using a Shack-Hartma...

introduction: to improve laser hair removal (lhr) for dark skin, the fluence rate reaching the hair follicle in lhr is important. this paper presents the results of a comparative study examining the function of wavelength on dark skin types using 755 nm alexandrite and 810 nm diode lasers. methods: the structure of the skin was created using a realistic skin model by the advanced systems analys...

Miniature laser sources with on-demand beam features are desirable devices for a broad range of photonic applications. Lasing based on direct-pump of miniaturized waveguiding active structures offers a low-cost but intriguing solution for compact light-emitting devices. In this work, we demonstrate a novel family of three dimensional (3D) photonic microstructures monolithically integrated in a ...