Triexcitons and their effect on absorption in the exciton region of the spectrum

Abstract

The effect of the triexciton state on the absorption of exciton-polaritons is studied under conditions when two high-power laser radiation pulses interacting with biexcitons and triexcitons and a probe pulse at the frequency of the exciton transition are incident on the medium. It is shown that even at low triexciton binding energies under the action of two high-power pulses, the exciton state splits into three quasi-levels, and the Autler--Townes effect (optical Stark effect) is observed. It turned out that the position of the quasi-levels depends on the detuning of the resonance of the pump pulses and their intensities, which makes it possible to identify them. These circumstances make it possible to diagnose the triexciton state in semiconductors with a higher degree of probability not by studying the absorption spectral line of the biexciton--triexciton transition, but by the effect of the triexciton state on absorption in the region of the exciton transition. Keywords: excitons, biexcitons, triexcitons, Autler--Townes effect.