A.V. Durrant

Electromagnetically induced transparency of laser-cooled rubidium atoms in three-level Λ-type systems

Abstract We have observed electromagnetically induced transparency (EIT) in laser-cooled rubidium in a magneto-optical trap (MOT). Λ-type configurations of hyperfine levels of the D2 line were studied, as well as a system utilising degenerate Zeeman sublevels of the ground state. V-type signals were also seen. The perturbing effects of the MOT were found to be small and the results agree well with standard EIT theory for homogeneously-broadened samples.

Resonant and off-resonant transients in electromagnetically induced transparency: Turn-on and turn-off dynamics

This paper presents a wide-ranging theoretical and experimental study of nonadiabatic transient phenomena in a L electromagnetically induced transparency system when a strong coupling field is rapidly switched on or off. The theoretical treatment uses a Laplace transform approach to solve the time-dependent density matrix equation. The experiments are carried out in a 87 Rb magneto-optical trap. The results show transient probe gain in parameter regions not previously studied, and provide insight into the transition dynamics between bare and dressed states.

Observations of a doubly driven V system probed to a fourth level in laser-cooled rubidium

Observations of a doubly driven V system probed to a fourth level in an N configuration are reported. A dressed-state analysis is also presented. The expected three-peak spectrum is explored in a cold rubidium sample in a magneto-optic trap. Good agreement is found between the dressed-state theory and the experimental spectra once light shifts and uncoupled absorptions in the rubidium system are taken into account.

Prospects for photon blockade in four-level systems in the N configuration with more than one atom

We show that for appropriate choices of parameters it is possible to achieve photon blockade in idealized one-, two- and three-atom systems. We also include realistic parameter ranges for rubidium as the atomic species. Our results circumvent the doubts cast by recent discussion in the literature (Grangier et al 1998 Phys. Rev. Lett. 81 2833, Imamoglu et al 1998 Phys. Rev. Lett. 81 2836) on the possibility of photon blockade in multi-atom systems.

Observation of transient gain without population inversion in a laser-cooled rubidium Lambda system

We have observed clear Rabi oscillations of a weak probe in a strongly driven three-level

Zeeman-coherence-induced transparency and gain without inversion in laser-cooled rubidium

\ensuremath{\Lambda}

Stochastic wavefunction diagrams for electromagnetically induced transparency, inversionless gain and shelving

system in laser-cooled rubidium. When the coupling field is nonadiabatically switched on using a Pockels cell, transient probe gain without population inversion is obtained in the presence of uncoupled absorptions. Our results are supported by three-state computations.

Photon echo relaxation in caesium perturbed by noble gases

Abstract We report experiments demonstrating the effects of optical pumping, coherent population trapping and light polarisation on electromagnetically induced transparency in simple Λ-type configurations of rubidium 87 where the relevant coherences are within the three Zeeman substates of the F=1 component of the 5S1/2 ground level. Inversionless gain is also demonstrated. The sample is cooled to below 1 mK in a magneto-optic trap operating without repumping light to give a working population of F=1 ground state atoms. The experimental results are compared with master equation computations of a closed seven-substate-model representing the ground level (F=1) and the excited levels F′=0 and F′=1.

Relaxation of Photon Echoes by Phase-interrupting Collisions during the Second Optical Pulse

Abstract A rigorous diagrammatic description of stochastic wavefunction evolution for electromagnetically induced transparency (EIT) and inversionless gain in coherently driven three-level systems is developed and applied to transient and steady-state conditions. Wavefunction trajectories are illustrated for cases that include A and V-type EIT, shelving and dressed-state resonances.

Elastic collision studies in caesium/noble gas systems using two-pulse echoes

Abstract The collisional relaxation of photon echoes generated on the 6S built1 2 - 7P built3 2 (455 nm) transition in caesium has been observed and measured as a function of perturber pressure. Values for the collision cross-sections have been obtained using helium, neon, argon and krypton as perturbers. There is good agreement between these results and those obtained from high resolution measurements of pressure-broadened line profiles. The echoes were observed using the polarization rotation technique and all the measurements were made at perturber pressures below 0.5 torr.