Abstract
In this paper, we investigate the emission spectrum of a two-level atomic system interacting with an optical radiation field based on photon-added coherent states of a pseudo-harmonic oscillator (PACSPHO). Also, the purity of the optical field initially prepared in the PACS-PHO is studied through the evolution of the field entropy. We examine the influence of the intensity-dependent field and the photon-transition number on the dynamic behavior of the emission spectrum and field purity. We explore the link between the field purity and the emission spectrum during the time evolution. Finally, we show how the emission spectrum is affected and changed according to the main physical parameters. We find that there is some kind of correlation between the emission spectrum and the field purity, which will be useful in different applications of quantum physics and spectroscopy.