Studies of the linewidth of dark resonances

Yandong Peng, Luling Jin, Yueping Niu +1 more

A scheme for obtaining a tunable ultranarrow linewidth of a cavity due to an embedded four-level atomic medium with double-dark resonances is proposed. It is shown that the steep dispersion induced by double-dark resonances in the transparency window leads to the ultranarrow transmission peak. Compared with the case of a single-dark resonance system, the linewidth can be narrowed even by one order under proper conditions. Furthermore, the position of the ultranarrow peak can be engineered by varying the detuning of the control field.

Peter R. Antoniewicz, Th.W. Ruijgrok

Ying Bo Kang, Yueping Niu, Dijun Chen +3 more

Cavity linewidth narrowing via double-dark resonances is experimentally observed using the Rb87 Zeeman splitting sublevels. With the steep dispersion led by the interacting dark resonances in the tripod-type electromagnetically induced transparency system, we narrow the cavity linewidth to 250 kHz at room temperature. Furthermore, the position of this ultranarrow cavity linewidth can be tuned in a 60 MHz coupling field detuning range.

Svenja A. Knappe, M. St�hler, C. Affolderbach +3 more

Sebastián Brandt, A. Nagel, R. Wynands +1 more

When neon is introduced as a buffer gas the interaction time of cesium atoms in a vapor cell with resonant laser beams is drastically increased. Using a pair of phase-locked lasers we have observed linewidths as narrow as $42 $Hz for coherent dark resonances in a cesium vapor cell. We study the influence of power and pressure broadening and systematic shifts of the resonance frequency. Our experiments demonstrate that coherent dark resonances could rival direct radio-frequency precision measurements, which have a wide range of applications in physics.

匡尚奇