S. A. Zibrov

Coherent-Population-Trapping Resonances with Linearly Polarized Light for All-Optical Miniature Atomic Clocks

We present a joint theoretical and experimental characterization of the coherent population trapping (CPT) resonance excited on the D1 line of 87 Rb atoms by bichromatic linearly polarized laser light. We observe high-contrasttransmissionresonances(upto ≈25%),whichmakesthisexcitationschemepromisingforminiature all-optical atomic clock applications. We also demonstrate cancellation of the first-order light shift by proper choice of the frequencies and relative intensities of the two laser-field components. Our theoretical predictions are in good agreement with the experimental results.

Pure superposition states of atoms generated by a bichromatic elliptically polarized field

We identify the specific polarizations for the two components of a bichromatic field, which produce pure superposition states of atoms with a specific magnetic quantum number m via coherent population trapping. The superposition states are composed of two Zeeman substates magnetic quantum number m of the two ground-state hyperfine levels with arbitrary angular momenta F{sub 1} and F{sub 2}. It is established that in the general case of m{ne}0, optical fields with elliptical polarizations are needed for the preparation of such a pure state. It is shown analitically that a unique advantage of the D1 line (over the D2 line) of alkali-metal atoms is the possibility that pure m-m states may be generated even if the excited-state hyperfine levels are not spectrally resolved.

Feedback spectroscopy of atomic resonances

We propose a non-standard spectroscopic technique that uses a feedback control of the input probe field parameters to significantly increase the contrast and quality factor of the atomic resonances. In particular, to apply this technique for the dark resonances we sustain the fluorescence intensity at a fixed constant level while taking the spectra process. Our method, unlike the conventional spectroscopy, does not require an optically dense medium. Theoretical analysis has been experimentally confirmed in spectroscopy of atomic rubidium vapor in which a considerable increase (one-two order) of the resonance amplitude and a 3-fold decrease of the width have been observed in optically thin medium. As a result, the quality factor of the dark resonance is increased by two orders of magnitude and its contrast reaches a record level of 260%. Different schemes, including magneto-optical Hanle spectroscopy and Doppler-free spectroscopy have also showed a performance enhancement by using the proposed technique.

New Doppler-free resonance in counterpropagating light waves

The resonance of saturated absorption in counterpropagating light fields is experimentally and theoretically studied. We focus on a case of parallel and linearly polarized waves, driving an open dipole transition in rubidium vapor. A new Doppler-free resonance within the saturated-absorption dip is revealed. The phenomenon can be gained only in absorption of strong wave in presence of weak one. The effect can not be explained basing on the previously known reasons. The results obtained can be found useful in metrology for the frequency and time standards.

New features of Doppler-free saturated-absorption resonance in field of counterpropagating waves

The resonance of saturated absorption in counterpropagating light fields is experimentally and theoretically studied. We focus on two cases: parallel and linearly polarized waves, driving an open dipole transition and the general case of elliptically polarized waves, driving closed dipole transition. The former reveals a new Doppler-free resonance as a peak within the saturated-absorption dip. The latter case reveals a new polarization effect, causing a shift and asymmetry of the saturated-absorption resonance. The results obtained can be found useful in metrology.

New Doppler-free resonance in field of counterpropagating waves

The resonance of saturated absorption in counterpropagating light fields is experimentally and theoretically studied. We focus on two cases: parallel and linearly polarized waves, driving an open dipole transition and the general case of elliptically polarized waves, driving closed dipole transition. The former reveals a new Doppler-free resonance as a peak within the saturated-absorption dip. The latter case reveals a new polarization effect, causing a shift and asymmetry of the saturated-absorption resonance. The results obtained can be found useful in metrology.

Magneto-optical resonances in elliptically polarized light field

Electromagnetically induced absorption (EIA) in Hanle configuration versus ellipticity of an optical running wave is investigated. All theoretical results are confirmed experimentally quite well. It is shown that magneto-optical resonance parameters (amplitude, width and amplitude-to-width ratio) depend on the wave polarization substantially. For example, the rsonance amplitude in the case of elliptic polarization of th elight wave can be the order more than for linear polarization.