12 research outputs found
Three-photon electromagnetically induced transparency using Rydberg states
We demonstrate electromagnetically induced transparency in a four-level cascade system where the upper level is a Rydberg state. The observed spectral features are sub-Doppler and can be enhanced due to the compensation of Doppler shifts with AC Stark shifts. A theoretical description of the system is developed that agrees well with the experimental results, and an expression for the optimum parameters is derived
Subnatural linewidths in two-photon excited-state spectroscopy
We investigate, theoretically and experimentally, absorption on an
excited-state atomic transition in a thermal vapor where the lower state is
coherently pumped. We find that the transition linewidth can be sub-natural,
i.e. less than the combined linewidth of the lower and upper state. For the
specific case of the 6P_{3/2} -> 7S_{1/2} transition in room temperature cesium
vapor, we measure a minimum linewidth of 6.6 MHz compared with the natural
width of 8.5 MHz. Using perturbation techniques, an expression for the complex
susceptibility is obtained which provides excellent agreement with the measured
spectra.Comment: 9 pages, 5 figure
Microwave dressing of Rydberg dark states
We study electromagnetically induced transparency (EIT) in the
5s5p46s ladder system of a cold Rb gas. We
show that the resonant microwave coupling between the 46s and 45p states leads
to an Autler-Townes splitting of the EIT resonance. This splitting can be
employed to vary the group index by allowing independent control of
the propagation of dark state polaritons. We also demonstrate that microwave
dressing leads to enhanced interaction effects. In particular, we present
evidence for a energy shift between Rydberg states resonantly coupled
by the microwave field and the ensuing breakdown of the pair-wise interaction
approximation.Comment: 12 pages, 5 figures and 1 tabl
Enhanced electric field sensitivity of rf-dressed Rydberg dark states
Optical detection of Rydberg states using electromagnetically induced transparency (EIT) enables continuous measurement of electric fields in a confined geometry. In this paper, we demonstrate the formation of radio frequency (rf)-dressed EIT resonances in a thermal Rb vapour and show that such states exhibit enhanced sensitivity to dc electric fields compared to their bare counterparts. Fitting the corresponding EIT profile enables precise measurements of the dc field independent of laser frequency fluctuations. Our results suggest that space charges within the enclosed cell reduce electric field inhomogeneities within the interaction region