Energy dependence of emission intensity and temperature in a LIBS plasma using femtosecond excitation

In this paper, we investigate the effect of laser energy on laser-induced b reakdown emission intensity and average temperature in a short-pulse plasma generated by using 140 fs laser excitation. Both line emission and continu um background intensity and plasma temperature decrease very rapidly after excitation compared to the more conventional nanosecond pulse excitation. B oth emission intensity and plasma temperature increase with increasing lase r energy. However, the intensity increase appears to he mostly related to t he amount of material ablated. Also, nongated laser-induced breakdown spect roscopy (LIBS) is demonstrated using a high-pulse (1 kHz) pulse repetition rate.