Abstract
We observed the transient oscillation in the spectra of electromagnetically induced transparency by rapidly sweeping the probe laser frequency. The spectra were measured with laser-cooled 87 Rb atoms. We show that the amplitude of the transient oscillation decays exponentially at a rate of Ω c 2 /2Γ, where Ω c is the Rabi frequency of the coupling laser and Γ is the spontaneous decay rate of the excited state. Using the transient oscillation, we demonstrate a simple method to determine Ω c . This method is particularly useful with the low-intensity coupling laser. © 2004 Optical Society of America.