Excitation and Stimulated Emission of Mn 2+ (3 d 5 ) in Manganese-Doped ZnCdS Quantum Dots in a Femtosecond Pump–Probe Experiment

model is constructed for the Mn^2 + ( 6 A) excitation in manganese-doped ZnCdS quantum dots (QDs) by a femtosecond laser pulse with the carrier frequency close to the frequency of the radiation transition between the edge of the valence band and the edge of the conduction band. The model is based on the fact that the excited 4 T state of the Mn 2+ ion localized close to the trapped electron with energy in the forbidden zone is mixed by the exchange interaction with the states of electrons in the conduction zone of the QD. The model describes the experimentally observed, at very short delay times between the pump and probe laser pulses, radiation stimulated by the probe pulse growing with an increasing delay time at a frequency corresponding to the transition 4 T → 6 A in Mn^2 + .