High resolution spectroscopy of Rb in magnetic field by far-detuning electromagnetically induced transparency

Abstract

We have presented a high resolution spectroscopy of Rb in magnetic field by far-detuning electromagnetically induced transparency (EIT). The EIT spectrum in the $\Xi$-type configuration is usually companied by a double resonance optical pumping (DROP) due to the strong optical coupling between the two upper states, leading to the spectral lines seriously deformed and widely broadened for complex relaxation processes in DROP. Here we demonstrate a high resolution spectroscopy by far-detuning EIT for $^{87}\rm{Rb}$ $\rm{5S_{1/2}\rightarrow5P_{3/2}\rightarrow5D_{5/2}}$ in magnetic fields. The method of far-detuning eliminates the relaxation in DROP to the most extent and decreases the spectral linewidth from more than 20 MHz down to its natural linewidth limit (6 MHz). The deformation of the spectral lines also disappears and the observed spectra are well in accordance with the theoretical calculation. Our work shows that far-detuning EIT is a reliable high resolution spectroscopic method when the relaxation in DROP can't be neglected, especially for the case of transition to low excited states.

Electric field intensity measurement by using doublet electromagnetically induced transparency of cold Rb Rydberg atoms

“…[16] An all-optical sensing method based on Rydberg electromagnetically induced transparency (EIT) is usually used to measure the electric field intensity because of the nondestructive detection mechanism. In general, the Rydberg EIT spectrum is observed by scanning the frequency of a probe (coupling) laser with an acousto-optic modulator (AOM), where the frequencies of both probe laser and coupling laser need to be locked by various techniques, [17,18] such as saturated absorption spectroscopy (SAS), EIT spectroscopy or Pound-Drever-Hall spectroscopy, etc. However, these frequency locking techniques need to be implemented in an elaborate experimental setup that may require expensive equipment and potentially timing sequence control.…”