the authors performed an experiment on sodium atoms in a well controlled m/sub l/ state. more precisely the experiment has been done on the sodium atoms of an atomic beam which are submitted to two laser excitations in the presence of a dc electric field. the first laser excitation is provided by a cw single mode dye laser right-hand polarized, tuned and servolocked on the transition 3/sup 2/s/sub 1/2/, f=2=3/sup 2/p/sub 3/2/, f=3: it thus permits exciting the sodium atoms in the pure state' 3 /sup 2/p/sub 3/2/, f=3, m/sub f/=3 which corresponds to the well defined magnetic orbital quantum number m/sub l/=1. the second laser excitation is provided by a nitrogen pumped dye laser continuously tunable over the range 408-413 nm, and polarized in either one of the sigma/sup +/, pi or sigma/sup -/ polarizations so that it permits to study the three different m/sub l/ projections of the photoionization spectrum' m/sub l/ =0, 1, 2 (the experimental configuration is set in such a manner that m/sub l/=0 and m/sub l/=2 photoionization spectra are obtained with the two laser beams counterpropagating collinearly, whereas m/sub l/=1 photoionization spectrum is obtained with the pulsed laser beam propagating perpendicularly to the cw one)