Fluorescence induced by resonant multiphoton ionisation near an autoionising state

Abstract

The authors study doubly resonant multiphoton ionisation induced by two laser fields. The first field produces a near-resonant multiphoton transition between the ground state g and a discrete state 0. The second field is nearly resonant with a one-photon transition between 0 and an autoionising state 1. The spontaneous emission of both excited states is taken into account. The authors discuss and compare the spectral profiles expected for ionisation probability and fluorescence from state 1 when the first step laser is scanned.