Abstract:We have experimentally studied the selective reflection spectra of a circularly-polarized laser beam from a sub-micrometric Rb vapor cell with a thickness L around λ/2 (λ = 780 nm being the laser wavelength tuned to the D 2 line) in the presence of a longitudinal magnetic field. Based on the results of these studies, we propose a new method for the tunable locking of the diode laser frequency, which does not require frequency modulation nor complex electronics. The experimental realization of the technique has demonstrated its effectiveness and its competitiveness with the known DAVVL-type methods. Response of the locked system to controlled laser diode temperature changes (upper trace) illustrated by the "anti-correlated" changes of the (feedback-controlled) injection current (lower trace)

We consider adiabatic interaction of five-level atomic systems and their media with four short laser pulses under the condition of all two-photon detunings being zero. We derive analytical expressions for eigenvalues of the system's Hamiltonian and determine conditions of adiabaticity for both the atom and the medium. We analyze, in detail, the system's behavior when the eigenvalue with nonvanishing energy is realized. As distinct from the usual dark state of a five-level system (corresponding to zero eigenvalue), which is a superposition of three states, in our case the superposition of four states does work. We demonstrate that this seemingly unfavorable case nevertheless completely imitates a three-level system not only for a single atom but also in the medium, since the propagation equations are also split into those for three-and two-level media separately. We show that, under certain conditions, all the coherent effects observed in three-level media, such as population transfer, light slowing, light storage, and so on, may efficiently be realized in five-level media. This has an important advantage that the light storage can be performed twice in the same medium; i.e., the second pulse can be stored without retrieving the first one, and then the two pulses can be retrieved in any desired sequence.

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