  We study spontaneous emission from an atom under the action of laser fields.
We consider two different energy level diagrams. The first one consists of two
levels resonantly driven by laser radiation where either of levels may decay to
a separate level. For such a system we show that the presence of the second
decay channel may deteriorate the destructive interference occurring in case of
one decay channel because of Autler-Townes effect. The second diagram
represents two two-level resonantly driven systems with the upper levels
decaying to a common level. For this diagram we show that there is no
interference between the two decay channels when the laser fields are described
in the Fock representation, while in case of definite-phase classical fields
such interference takes place and is partially or completely destructive or
constructive depending on the initial conditions and on the mutual orientation
of the spontaneous emission dipole moments.
