Enhancement of the selectivity of laser photoionization analysis in the case of twopulse interaction of an electric field with Rydberg atoms

A new method is proposed for a significant (by 3–4 orders of magnitude) enhancement of the selectivity of laser photoionization detection of atoms in a complex atomic-molecular medium. The method is based on the excitation of such atoms by laser radiation to Rydberg states and their selective detection by ionization with two pulses of an electric field of different polarities and amplitudes. It is reported that boron impurities present in a concentration of 10^-8% in highpurity germanium can be detected by this method; this level of selectivity is much higher than that in the conventional photoionization analysis.