Resonant and Nonresonant Nonlinear Absorption in Colloidal Core/Shell Semiconductor Nanoplatelets

Nonlinear absorption of colloidal solution of core/shell CdSe/CdS nanoplatelets (NPLs) in the case of resonant and nonresonant stationary excitation of the electron/light-hole and electron/heavy-hole exciton transitions was investigated. We have revealed the induced bleaching simultaneously of both exciton transitions. The peculiarities of the nonlinear change in absorption were associated with saturation of exciton transitions absorption due to phase space filling, energy up- and down-conversion mechanisms.