Abstract:
Probe field propagation through a four-level Y-type system is studied analytically
under steady state condition by using density matrix formulation. The probe field scans the
intermediate state from the ground state whereas two other coherent radiation fields, namely
the control field and the coupling field, are set to couple two different excited states from the
intermediate energy level. Under Doppler free condition, simulated probe absorption shows
single or twin EIT windows depending on whether the control and the coupling field are onresonant or detuned. Under Doppler broadened condition, the residual Doppler averaging due
to wavelength mismatch between the probe field and the control field as well as that between
the probe field and the coupling field plays significant role in the formation of transparency
window.
