Paper Details

A density matrix based analytical model is developed to study the coherent probe field propagation through afour-level ‘V’ type system in presence of a coherent control field. The four-level system comprises of two ground levelsand two upper levels. The model allows coupling of the probe field from the upper ground level to both of the excitedlevels whereas the control field is kept locked from the upper ground level to one of the excited levels. The addition of anextra ground level to a conventional three-level ‘V’ type system creates extra decay paths to the ground levels from theupper levels. A set of sixteen density matrix based equations are formed and then solved analytically under rotating waveapproximation to study the probe response under steady state condition. Under Doppler free condition the simulatedprobe absorption shows EIT but under thermal averaging the EIT window displays signature of absorption at its middle.The absorption dip exhibits shift as well as broadening with variation in the control Rabi frequency. This is termed asfield induced absorption.

Khairul Islam, Arindam Ghosh, Suman Mondal, Dipankar Bhattacharyya, Amitava Bandyopadhyay, “Formation of field induced absorption in the probe response signal of a four-level ‘V’ type atomic system: a theoretical study”, International Journal of Advance Engineering and Research Development (IJAERD), Vol. 3, Issue 6, pp. 138-146, June 2016.