Figure 4

Measured EIT signals versus coupling laser detuning. When there is no RF field, we obtain a reference EIT with a peak at 0 MHz coupling detuning. Once the atoms are exposed to the RF field at 638 MHz, the EIT spectrum shifts to the right according to the ac Stark effect. In the absence of the resonator, the output power of the SG is 17 dBm with a Stark shift of 13.9 MHz, while in the presence of the resonator, the output power drops to −17 dBm resulting in the same Stark shift of the EIT spectrum