Diode lasers in analytical chemistry

In this review article, I report the structure and characteristics of a diode laser and the figure of merits in the application to analytical spectroscopy. This diode laser is currently used an absorption-based and fluorescence-based spectrometries. Due to their ultra-high detectability, single atoms and molecules can be detected in the extreme case. Moreover, selectivity is improved by time-resolved spectrometry and also by a combination with separation techniques such as chromatography. Second harmonic generation is employed to extend the laser wavelength, in order to expand the analytical application. Finally, limitations of the diode laser are pointed out, and the problem, which should be solved in the near future, is also described. (C) 1999 Elsevier Science B.V. All rights reserved.