Decoherence suppression of excitons in semiconductor using sequential femtosecond pulses

We demonstrate the decoherence control of excitons on a layered compound semiconductor GaSe by using successive femtosecond pulses. The intermediate pulses act as π pulses, which reverse the time evolution of non-Markovian dynamics. By changing the incident timing of the π pulses, we determine the effective pulse interval condition for suppressing the decoherence of excitons by optical pulse irradiation.