The atomic decoherence effect (DCE) on electromagnetically induced transparency (EIT) is studied in the phase-sensitive \(\Delta\) system. The DCE forces the susceptibility of the medium into negative or positive depending upon the resultant phase and the microwave field (MWF) strength. In general, the phase-sensitive amplification (PSA) on the probe resonance laser field is induced by the MWF. The DCE plays a major role in tuning the PSA in the \(\Delta\) system. In this system, controlling the ground state decoherence leads to an amplification in the output of the probe field. The DCE is of great interest in the field of quantum information science, and quantum optics. The EIT and Autler-Townes splitting (ATS) have been discussed in a phase-sensitive \(\Delta\) system and it is found that the decoherence does not contribute in switching from EIT to ATS.
