Differential Absorption Features of CdSe QDs in the Case of Resonant and Nonresonant Excitons Excitation

Nanosecond differential absorption measurements of spherical CdSe QDs at the quasi-stationary resonant and nonresonant excitation of basic exciton transitions are reported. The significant decrease in absorption and saturation of the basic exciton transition 1Sh3/2–1Se are explained by the state filling effect. The observed blue shift of differential absorption minima with increasing pump intensities was explained by strong exciton–phonon interaction. In addition, the 2Sh3/2–1Se exciton transition bleaching and induced absorption of mixed 1Ph3/2–1Pe and 2Sh1/2–1Se exciton transitions were found.