SPATIALLY AND TEMPORALLY RESOLVED TEMPERATURE-MEASUREMENTS OF PLASMA GENERATED IN PERCUSSION DRILLING WITH A DIODE-PUMPED ND-YAG LASER

Results of spectroscopic temperature measurements of the laser-induced plasma generated during percussion drilling with a high power diode-p umped, pulsed Nd: YAG laser are presented. SAE 52100 steel was drilled with varying average powers. Helium and oxygen were each used as the shield gas. Emission spectra were collected with a monochrometer and a n intensified charge coupled detector connected to the optical multich annel analyzer. The plasma electron temperatures were calculated from the relative intensities of the spectral lines. The spatial and tempor al temperature distributions are presented. Both drilling times and sp atial distributions indicate energy absorption by the plasma. (C) 1998 American Institute of Physics. [S0021-8979(98)02220-8].