Abstract
The detection sensitivity of methalic atoms by means of the resonant fluorescencemethod and the selective photo-ionization method with tunable dye laser is analyticallyand experimentally studied. The theoretical detection limit of less than 0.1 atom/cm3can be achieved in both methods. Even the real time detection of individualatomscrossing the laser beam is expected, if sophisticated systems are prepared. Since thefluorescence method and the photo-ionization method are in a marked contrast in theircharacteristics, the advantage and disadvantage of these methods are discussed fromvarious view points.