Pulsed laser for machining aluminium or similar material - is modulated at natural frequency of oscillation, either in cavity or by modulation of pump source

摘要

The laser action is excited in a conventional arrangement of a medium (4) between two mirrors (5, 6) arranged parallel to reduce losses in the cavity. Emission (7) is extracted with the aid of an exit mirror. The beam is modulated weakly either by loss modulation in the medium (4), or by modulation (8') of the optical pumping, at the natural frequency of the laser. Pulses of width 1 to 10 microseconds can be produced with e.g. a piezoelectric acousto-optical modulator. ADVANTAGE - Higher quality of machined surfaces is achieved with little or no redn. in mean power.