Abstract: An assembly for processing a work piece using a laser beam, in particular for processing a highly reflective work piece, includes a fiber laser as a laser beam source for producing a pulsed primary laser beam having a bandwidth that is less than 1 nm.

Abstract: A laser machining method includes A) generating, by a laser source, a laser beam having an initial wavelength between 700 and 1200 nanometers of laser pulses; B) doubling frequency of one part of the laser beam by a non-linear crystal; C) varying power throughout each emitted laser pulse so that the power profile has a maximum peak power or part of the pulse with a maximum power in an initial sub-period, and throughout an intermediate sub-period of longer duration than the initial sub-period, a lower power than the maximum power. The maximum power value is at least two times higher than the mean power throughout the laser pulse and an increase time to maximum power from a start of each laser pulse is less than 0.3 milliseconds. The machining method can concern welding highly reflective metals, copper, gold, silver, or an alloy including one of these metals.