Time-resolved laser induced breakdown spectroscopic study of copper plasma

The line broadening mechanism of emission lines for the copper plasma is investigated by studying three atomic emission lines observed at 510.55 nm, 515.32 nm and 521.82 nm with the the time-resolved laser induced breakdown spectroscopy (Libs). The line observed at 510.55 nm showed no obvious change in linewidth as the delay time of the gate from the laser pulse is increased, while lines at 515.32 nm and 521.82 nm are identified to have a great change in line shape along the expansion. The broad linewidth for 515.32 nm and 521.82 nm lines observed at short time delay cases are attributed to the Rydberg like atomic behavior of the starting level of the emission process. This is because the starting level for 510.55 nm emission line is a bound state while the other two emission lines originated from the Rydberg states. The effect of laser power on the line broadening for those three lines is identified as minimal. In addition the laser induced copper plasma are analysed to behave similar to the supersonic jet expansion due to the very intense laser light.