By cascaded excitation using an 852-nm continuous-wave laser and a 509-nm nanosecond pulsed laser, the electromagnetically-induced transparency (EIT) spectroscopic signals of ladder type three-level cesium atoms with Rydberg state have been achieved using a room-temperature cesium vapor cell. The 509-nm pulsed laser beam’s power is ~176 W, while the pulse repetition frequency ranges from 300 kHz to 100 MHz and can be continuously adjusted. The laser pulse duration ranges from 1 to 100 ns and can be continuously adjusted. The relationship between Rydberg EIT spectroscopic signals and 509-nm nanosecond pulsed laser parameters have been experimentally investigated. By changing the pulse repetition frequency and the pulse duration of the 509-nm nanosecond pulsed laser, the comb-like Rydberg atomic spectroscopy has been achieved using a room-temperature cesium vapor cell. Under certain repetition frequency and pulse duration ranges, the envelope of the spectral lines shows a regular pattern, the spacing between the transmission peaks is consistent with the pulse repetition frequency, and atomic with the specific velocity group can be excited to Rydberg state by changing the values of the 509-nm laser pulse repetition frequency and pulse duration. Theoretically, the center peak frequency can be tuned to within ±100 MHz of the velocity group atoms' excitation in Rydberg state for the pulsed laser parameters.
Compared with finite velocity group pumping of cesium atoms by a continuous-wave laser, decreasing the repetition frequency of the 509-nm pulsed coupling laser can further increase the number of atoms in Rydberg state. When the repetition frequency of the 509-nm pulsed laser approaches the EIT linewidth, the number of cesium Rydberg atoms can be increased by up to 10 times. During the parameter optimization process, the dynamic characteristics of pulsed excitation in multi-level atoms, as well as the interaction characteristics between arbitrarily shaped laser pulses and multi-level atomic systems, should be considered. Pulsed laser pumping enables the interaction between the laser field, and a specific velocity group of atoms and the atomic frequency comb spectroscopy developed from it can be used for electric and magnetic field measurements. The multi-peak structure of the spectrum can be used to more accurately determine the intensity, frequency, and phase of the microwave electric field by measuring spectral variations. This high-sensitivity and high-resolution measurement capability is crucial for the precise measurement of microwave electric fields. The pulse coupling laser can excite atoms in a specific velocity group to the Rydberg state. High-density Rydberg atoms can improve the signal-to-noise ratio of the measured spectrum, which has potential application in quantum sensing and quantum measurement based on Rydberg atoms.