Editor's Notes

I think it is safe to say that ten years ago few prognosticators would have picked laser plasma spectroscopy as the next hot topic in the area of elemental analysis. It didn’t take much insight to see a long list of reasons why laser-generated plasmas would not make it as analytical tools. Lasers were expensive and Ž nicky. Laser sampling was irreproducible and depended strongly on the form and composition of the sample. The interaction of a laser beam with a solid surface was strongly affected by the atmosphere in which the experiment was performed. Emission spectra from laser-induced plasmas were messy, with broad lines and intense continuum backgrounds. It was easy to be a naysayer. Of course the history of laser ablation as a tool for elemental analysis goes back much further than ten years. Ben Smith at the University of Florida has graciously supplied me with some of the important historical milestones in the development of laser plasma spectroscopy as an analytical tool. In June of 1962, Fred Brech from Jarrell Ash presented a paper entitled ‘‘Optical Micromission Stimulated by a Ruby Maser’’ at the tenth CSI meeting. An abstract of the paper was published in this journal.1 Jarrell Ash announced the development of a commercial laser microprobe in 1963, and full-page ads for the instrument appeared in Analytical Chemistry in 1964. Despite its initial promise, the technique languished with little attention for nearly thirty years. One is left wondering what caused the current burst of activity with respect to an old idea after it had lain dormant for so long. I don’t have a carefully researched, deŽ nitive answer to the question, but it is fun to engage in some speculation. One obvious answer is that the technology for successful use of laser plasmas lagged behind the development of the idea. The photographic Ž lm used in the early instruments was inconvenient and could not be gated. The low repetition rate of ruby lasers precluded the effective use of gated, single-channel detectors. However, a lack of suitable technology alone cannot explain the slow development of laser plasma spectroscopy as an analytical technique. There was not a sudden burst of activity in the Ž eld of laser plasma spectroscopy coincident with the commercial introduction of gated array detectors. I suspect that a number of other factors contributed to the slow emergence of laser plasma spectroscopy as an analytical tool. One is that during the decades in which laser plasma spectroscopy was being ignored, most atomic spectroscopists were preoccupied with the emerging techniques of ICP-AES and ICP-MS. These techniques presented enough fertile ground for research activity to ensure that their limited ability to deal with solid samples could be pushed to the background. A second possible factor is that there is something more intellectually appealing about using a laser as a spectroscopic scalpel than using it as an optical sledgehammer. The laser jocks focused their attention Ž rst on absorption,  uorescence, and ionization spectroscopies and turned their attention on laser plasmas only after the spectroscopic uses of lasers for elemental analysis were forced into ever shrinking niches by the spectacular success of ICP-MS. We are fortunate, I think, that a few scientists had the insight to recognize that the liabilities of laser plasma spectroscopy could be offset by some very important advantages, and then had the tenacity to prove that the technique could work. Among those advantages are noncontact sampling of virtually any material, high spatial resolution, and adaptability to remote sensing. Research reports exploiting these characteristics are appearing in the literature with increasing frequency, particularly in this journal. In the current volume of Applied Spectroscopy, half of the atomic spectroscopy papers deal with laser plasmas in some form. Applied Spectroscopy is emerging as a prime outlet for analytical laser plasma research. As one who doubted ten years ago that laser plasma spectroscopy would have a signiŽ cant long-term impact, I am reluctant to predict its future. It is a safe bet, however, that laser plasma spectroscopy is here to stay. The future of the technique looks bright. The use of versatile solid-state lasers with ultrashort pulses coupled with improved detector and spectrometer technology can only build on the solid foundation that has already been laid. Keep the papers coming!