We propose the method of rapid adiabatic passage to prepare a single molecu
le in its fluorescing excited state. Spontaneous emission from this state g
ives rise to a single photon. Since the adiabatic passage can be performed
on command, the molecule can be used as a triggered single photon source. P
reliminary experiments and quantum Monte-Carlo simulations demonstrate the
feasibility of this scheme. (C) Academie des Sciences/Elsevier, Paris.