Cavity linewidth narrowing by optical pumping-assisted electromagnetically induced transparency in V-type rubidium at room temperature

A detailed experimental investigation is made in the intracavity V-type electromagnetically induced transparency (EIT) of the Rb atomic medium at room temperature. The optical pumping effect will increase the transparency for the V-type EIT at room temperature and therefore the cavity linewidth can be narrowed apparently. For the seven EITs observed in our previous study, cavity linewidth narrowing is observed in all of them. More importantly, we find that the cavity linewidth can keep at 1.2 MHz over a wide frequency range of 100 MHz by utilizing the central double-peak-structure EIT. This property provides a novel way for constructing a high resolution tunable frequency reference via the intracavity EIT.