He-4 2 S-3(1)-->2(3)P transitions at 1083 nm were laser probed in the
presence of radiation that coupled the 2(3)P level with the 3(3)S(1) l
evel in a ladder scheme. The metastable helium that was used was produ
ced in a rf discharge. Significant atomic birefringence was detected,
in addition to complete electromagnetically induced transparency. A si
mple theoretical model explains the experimental results. (C) 1997 Opt
ical Society of America.