Density matrix reconstruction of three-level atoms via Rydberg electromagnetically induced transparency

Abstract

We present combined measurements of the spatially-resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, whilst the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full onebody density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and light degrees of freedom and will facilitate new studies of many-body effects in optically driven Rydberg gases.The experimental and theoretical investigation of ensembles of Rydberg atoms driven by laser fields is currently attracting a great deal of interest [1,2,3]. For instance, the exceptional properties of Rydberg atoms, such as their tunable longrange interactions and the Rydberg blockade effect, provide new avenues to investigate strongly correlated many-body physics [4,5,6,7,8,9,10,11,12], to implement quantum

Sub-Poissonian atom-number distributions by means of Rydberg dressing and electromagnetically induced transparency

“…There is an approximate way to estimate the decay rate Γ N by using the optical Bloch equations of a threelevel atom in an EIT configuration. The population in the intermediate state |e of the stationary solution is given by [61]…”

Interaction Enhanced Imaging of Rydberg P states

“…(24). Only the measurement of the coupling Rabi frequency Ω r = Ω c is independently realized using a method based on a local fitting of the electromagnetically-induced transparency profile [75]. By performing three-photon spectroscopy at different Ω e ( fig.…”

“…Because of the small size of the sample compared to the extension of the coupling beam, we assume Ω c to be constant, equal to 26.2 ± 2.3 MHz according to independent measurements [75]. This choice is relevant since we clearly observe in fig.…”

Paschen-Back effects and Rydberg-state diamagnetism in vapor-cell electromagnetically induced transparency

“…In the Rydberg-EIT cascade scheme [3], the transparency is formed by a coherent superposition of the ground state and the Rydberg state. Rydberg-EIT has been implemented in both cold atomic gases [4,5] and in room-temperature vapor cells [3,6]. It has been widely used as a nondestructive optical detection technique for Rydberg spectroscopy [7,8], quantum information processing [9] and measurements of weak [10,11] and strong [12,13] microwave electric fields.…”