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

Abstract

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 1S_h3/2–1S_e 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 2S_h3/2–1S_e exciton transition bleaching and induced absorption of mixed 1P_h3/2–1P_e and 2S_h1/2–1S_e exciton transitions were found.