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 <sup>87</sup>Rb atoms. We show that the amplitude of the transient oscillation decays exponentially at a rate of Ω<sub>c</sub><sup>2</sup>/2Γ, where Ω<sub>c</sub> 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<sub>c</sub>. This method is particularly useful with the low-intensity coupling laser.
© 2004 Optical Society of America
Yong-Fan Chen, Guan-Chi Pan, and Ite A. Yu, "Frequency-modulation-induced transient oscillation in the spectra of electromagnetically induced transparency," J. Opt. Soc. Am. B 21, 1647-1650 (2004)