Determination of sign during phase correction of sign-variable modulation spectra of intersubband light absorption in GaAs/AlGaAs quantum wells

Abstract

Modulation of intersubband light absorption in GaAs/AlGaAs quantum wells under external impact may contain different sign peaks. In this work, we show that fast Fourier transform may give mistakes in negative modulation intensity during the phase correction of obtained interferogram of absorption modulation. We have demonstrated that information about the spectrum sign could be extracted from the phase spectrum. Sign mistake could be eliminated using the phase correction with modified phase spectra during the fast Fourier transform.