Laser-Induced Transparency in CdSe Nanoplatelets under Conditions of the Optical Stark Effect

We report the results of a study of laser-induced transparency under the conditions of the optical Stark effect in CdSe nanoplatelets. The induced absorption spectra are measured by the pump–probe technique. Laser-induced transparency is observed due to the transfer of the population of the electron states of the valence band to the conduction band as a result of two-photon optical transitions under the action of pump radiation. The transparency of the medium is maintained for the lifetime of the first excited exciton level, which corresponds to 180 ps. The presence of a hypsochromic shift of the exciton absorption band by 3.1 meV for a pump power density of 39 GW/cm² with the coincidence of pump and probe pulses due to the optical Stark effect is demonstrated. The results of fundamental studies presented in this paper can find application in the development of new photonic devices for controlling light with light.