Coherence effects in the bichromatic excitation of Rb

Daba A. Radnatarov, Sergey Khripunov, Sergey M Kobtsev +6 more

This work reports on possibilities of contrast enhancement of dynamically excited coherent population trapping (CPT) resonance in 87Rb vapour arising from application of feedback methods. Controlling the bichromatic pump radiation power through a feedback loop that stabilises Rb atom luminescence when scanning the frequency difference of the bichromatic pump radiation resulted in a more than an order-or-magnitude improvement in the amplitude of the CPT resonance at scanning frequencies over 100 Hz. It is established that the excursion of the pump radiation power controlled by the feedback loop under dynamic excitation is by an order of magnitude smaller than that under quasistationary excitation at scan frequencies < 1 Hz.

Zhuo Song, Yujun Zheng

Marc C. de Lignie, D.A. van der Sijs, E. R. Eliel

M. R. Williams, F. Chi, M. Cashen +1 more

The limit of $\ensuremath{\Elzxh}k\ensuremath{\gamma}/2$ imposed on the magnitude of radiative forces by the spontaneous decay rate $\ensuremath{\gamma}$ of the excited state can be overcome by coherent control of the momentum exchange between atoms and the light field. This can be implemented with two light beams, each containing two frequencies whose phases, amplitudes, and frequency difference are carefully chosen. We have made precise measurements of the extremely large magnitude and velocity range of this bichromatic force, and have shown that its velocity dependence near the edge of its range is suitable for atomic beam slowing and laser cooling. Our measurements have corroborated various models and calculations of this bichromatic force.

Jarett L. Bartholomew

A. V. Taichenachev, Valeriy I. Yudin, Vladimir L Velichansky +1 more

We propose and study, theoretically and experimentally, a new scheme of excitation of a coherent population trapping resonance for the D1 line of alkali atoms with nuclear spin I = 3/2 by bichromatic linearly polarized light (lin‖lin field) under the conditions of spectral resolution of the excited state. The unique properties of this scheme result in a high contrast of dark resonance for the D1 line of 87 Rb.