HIGH POWER LASER PROCESSING HEAD AND HIGH POWER LASER PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a high power laser processing head having the function of monitoring the accumulation of spatter ejected from a workpiece via a probe beam which can implement precise and sensitive detection by suppressing effects of variations in probe beam position and reducing effects of low frequency noise.SOLUTION: The high power laser processing head includes a condenser lens 1 for focusing processing laser light 3 modulated in power to a fixed frequency of 100 Hz to 10,000 Hz on a workpiece, a cover glass 5 positioned between the condenser lens 1 and the workpiece 4, a light source 8 for radiating a probe beam 6 to the cover glass 5, a position sensor 7 for detecting the deflection direction of the probe beam 6 transmitted through or reflected by the cover glass 5, and a signal processing circuit for extracting a frequency component centered on the modulation frequency of the processing laser light 3 from the output signal from the position sensor 7. The amplitude of the extracted signal is evaluated as the amount of absorbing impurities attached to the cover glass 5.