Gaussian field induced spectral hole burning in a Doppler broadened system and spontaneously generated coherence

The hole burning phenomenon is investigated for a four-level N-type atomic system interacting with three electromagnetic fields. The fields have a typical Gaussian transverse profile, in the presence of a Doppler broadening medium and spontaneously generated coherence due to nearby decaying levels. We present numerical results for the probe susceptibility via non-perturbative treatment of the density matrix elements solution. Some interesting features are enhanced for the spectral hole burning behaviors such as gain spectral hole burning and resonant fluorescence line narrowing. Also, the phenomenon of suppression of spectral curve, the propagation of slow and fast light in the system have been focused.