Line broadening of electromagnetically induced transparency at high optical power

Abstract

We observe electromagnetically induced transparency (EIT) in Rb vapor at various optical intensities, starting from below saturation to several times the saturation intensity. Solving the time dependant density matrix equation of motion with a phenomenological decay constant, we find an expression suitable in explaining the EIT signal. In this experimental observation and corresponding theoretical analysis of EIT signal we conclude that Lorentzian width of EIT signal increases with Rabi frequency but the net change of width is lower than the corresponding change in Rabi frequency.