Abstract

We investigated a three level A-system falling in a homogeneous gravitational field. It is exposed to two counterpropagating laser fields with wave vector $\pm \overrightarrow{k}$, which Induce Raman transitions, and to a magnetic hyperfine field tuned to be in resonance with the transition between the two ground states |+〉 and |−〉 (comp. Fig. 1). For sufficiently large detuning the excited state can be eliminated adiabatically. It remains a.) Rabi flopping between the states |+〉 and |−〉 caused by the magnetic field (no accompanying change of momentum), and b.) transitions between these states with momentum transfer $\pm 2\hslash \overrightarrow{k}$ happening for certain values of the center-of-mass momentum. These gravito-optical transitions go back to the combined influence of the gravitational field and the laser field. They turn out to be of the Landau-Zener type.

© 1996 IEEE