Multiphoton Ionization Enhancement Using Two Phase-Coherent Laser Pulses

Abstract

Modulations in the multiphoton ionization yield in Na are observed as a function of the relative delay between two identical 150 fsec laser pulses. The first pulse populates a coherent superposition state composed of ground and excited levels. The ionization yield during the second pulse depends on its phase relative to that of the nonstationary superposition state. Ionization enhancements of more than an order of magnitude can be achieved by exploiting coherences in the atom-laser system.