Effect of neighboring transitions on the transformation between electromagnetically induced transparency and two-photon absorption

Abstract

We report the effect of neighboring transitions on the transformation between electromagnetically induced transparency (EIT) and two-photon absorption (TPA) in an open multi-level ladder type system of 87Rb atom, the EIT peak exhibits split and asymmetric line feature owing to a neighboring transition line with a stronger relative hyperfine transition strength factor. By comparing the signals of the 5S1/2−5P3/2−5D3/2,5/2 transitions when increasing the power of the coupling laser, it can be found that avoiding neighboring effects due to Doppler broadening in a real atom, a lower decay rate of the excited state and a higher hyperfine transition strength ratio between the coupling and probe lasers are the crucial factors that enhance the transformation efficiency between TPA and EIT and the resolution of the switched spectra. Detailed theoretical calculations, considering the crucial factors, are consistent with the experimental results.