Patent ID: 7372878
Filing Date: 2008-05-13
Classification: B23K,H01S

Abstract:
1. A method for decreasing the amount of undesired laser radiation reaching a workpiece from a laser having a laser cavity and a Q-switch, the laser operating at any given time in one of at least two modes, a first mode in which the laser emits pulses at a pulse repetition frequency for selectively irradiating targets on or within a workpiece, the pulses propagating along a propagation path to the workpiece, and a second mode, which is an idle mode in which no laser radiation desirably reaches the workpiece, the method being operable during the second mode, the method comprising: opening the Q-switch more than the Q-switch is open in the first mode, thereby limiting the amount of energy that builds up in the laser cavity and decreasing the peak energy of the laser radiation emitted in the second mode, wherein the opening step comprises repeatedly closing and opening the Q-switch at a rate greater than the PRF, thereby causing the laser to emit more rapid and less energetic pulses than in the first mode; and substantially preventing the more rapid and less energetic pulses from reaching the workpiece.