Band gap renormalization of the InSe by laser radiation

Abstract

Nonlinear absorption of light and its time evolution in InSe under the influence of picosecond laser excitation have been investigated experimentally. It was shown that the decrease in exciton absorption in InSe at high levels of optical excitation is due to the exciton–exciton interaction and screening of the Coulomb potential by free carriers, generated by laser light. Observations of induced absorption in the energy region between the exciton level and the edge of the conduction band are associated with the appearance of a continuum of states due to a shift in the edge of the energy band.