Experimental studies of photon echo in nanoscale films

The main activity is experimental studies on the two-photon excitation of the femtosecond signal of the primary photon echo in a semiconductor zinc oxide film of nanoscale thickness (100, 600 and 800 nm) at a quantum transition corresponding to 400 nm at room temperature. The photon echo was observed on free excitons. The echo signal, partially attenuated due to scattering by optical phonons, was recorded at a wavelength of 800–840 nm. The nanoptical effect of reducing the time of the irreversible transverse relaxation of the T2 medium with a decrease in the film thickness was found. The established fact is associated, firstly, with the structural feature of the films under study and, secondly, with a decrease in the intensity of the longitudinal interactions of the excited particles with decreasing film thickness.