Dependence of the ⁸⁵Rb coherent population trapping resonance characteristic on the pressure of N₂ buffer gas

In order to exploit its potential applications, we experimentally study the dependence of ⁸⁵Rb-based coherent population trapping (CPT) resonance on N₂ buffer gas with 6 vapor cells filled with natural rubidium and N₂. The experiments are carried out at different pressures and temperatures, and the results reveal that higher cell temperature makes the resonance more sensitive to N₂ pressure. Thus, it is important to choose a proper buffer gas pressure at a given cell temperature. This work provides valuable data for the application of ⁸⁵Rb CPT resonance with a buffer gas of N₂.