A modified laser probe for spectrochemical analysis is described. A high energy laser beam is focused onto a specimen to vaporize a sample from a small area, and the vapor thus formed is further excited by a spark discharge. The characteristics of emission spectra with and without auxiliary spark excitation are compared. Spectrograph illuminating systems for qualitative and quantitative analysis were investigated. Some difficulties were encountered with the laser probe, and modifications were made to the instrument to alleviate some of these problems. Some typical analytical applications are discussed.
Stanley D. Rasberry, Bourdon F. Scribner, and Marvin Margoshes, "Laser Probe Excitation in Spectrochemical Analysis.I: Characteristics of the Source," Appl. Opt. 6, 81-86 (1967)