Abstract
We studied the spectrum of electromagnetic induced transparency (EIT) driven to Rydberg states using room-temperature 87Rb atoms. We can divide this article into theory and experiment two parts. In the first part, we introduce the analytical transmission maximum theory of cascade EIT (chapter 1) and some experimentally parameters such as transition frequency to Rydberg state, coupling Rabi frequency etc…(chapter 2) In the future, we can calculate these parameters to predict the experiment result. In the second part, chapter three is the experimentally details of our EIT system, which is a probe field drove the transition from a 5S1/2 ground state to a 5P3/2 excited state, and a coupling field drove the transition from the 5P3/2 state to a Rydberg state of 55D5/2 or 57S1/2. The two fields form the cascade EIT scheme. We measured the EIT peak height in transmission as a function of the probe Rabi frequency at different polarization configurations, orbital, principle number and coupling power. The data showed that the EIT peak height reaches a maximum at an optimum probe Rabi frequency instead of monotonically decreasing with the probe Rabi frequency. We also thought whether a saturated absorption system has the same phenomenon. Because the system is also formed by a strong saturation beam and a weak probe beam counter propagating through the cell (chapter 4). Finally, in order to simulate frequency locked of blue laser, we studied the differential spectrum of 795 nm laser with EOM. We can modulate the Rydberg EIT signal with EOM to lock the blue laser’s frequency in the future.