Coherence Effects in Two Photon Absorption in Atomic Cesium Vapor.

Isaac D. Abella

Chang‐Hee Hong

A large increase of atomic absorption via atomic coherence is observed in Cesium atoms in the condition of off resonance in degenerate two-level atomic systems. We show that when on resonance, the reduction of atomic absorption via EIT accured. But when we tune the coupling field on the off resonance, the enhancement of absorption via EIA is obtained for the probe field. The influences of the two-photon detuning and intensity of coupling field on the absorption are also studied experimentally.

M. S. Pindzola

Gang Li

Employing an intense laser field coupling to the degenerate two-level system of cesium 6 2S_ 1/2(F=4)- 6 2P_ 3/2(F′=5) transition in a cesium vapor cell, electromagnetically induced absorption (EIA) has been demonstrated via probe absorption spectra, at the same time, electromagnetically induced transparency (EIT) of V-type three-level scheme has been demonstrated on the F=4-F′=3 and F=4-F′=4 transition frequency. The EIA is affected by the intensity and detuning of the coupling laser. By analyzing the effect of optical pumping between Zeeman sub-levels on the EIA and the coherent interactions between multiple degenerate two-level atoms, it is shown that the optical pumping affects the population of different Zeeman sub-levels and the number of the involved two-level atoms, the coherent time between the sub-levels is then changed and the linewidth and intensity of the EIA are affected accordingly.

Salvatore Carusotto, ERSEO POLACCO, Moreno Vaselli

X. Zhang, J. B. Kim, D. Antypas

We report on observations of coherent, sustained oscillations in the absorption of continuous-wave light at 388 nm that excites the 6 S 1/2 → 8 P 3/2 transition in cesium (Cs) vapor. The oscillation frequency is close to the spacing of hyperfine levels of the 8 P 3/2 level that are excited simultaneously by the 388 nm field. We observe a threshold behavior of the oscillation amplitude with pump power and suggest that the effect is associated with infrared directional emission due to amplified spontaneous emission (ASE) from the 8 P 3/2 → 8 S 1/2 transition that is assisted by retro-reflections from cell windows. The effect may be used to probe a lasing process in an atomic vapor, by checking the temporal properties of the pump field transmitted through the vapor.