Coherent excitation of Rydberg atoms in micrometre-sized atomic vapour cells

Abstract

The coherent control of mesoscopic ensembles of atoms and Rydberg atom blockade are the basis for proposed quantum devices such as integrable gates and single photon sources. So far, experimental progress has been limited to complex experimental setups that use ultracold atoms. Here, we show that coherence times of ∼ 100 ns are achievable with coherent Rydberg atom spectroscopy in µm sized thermal vapor cells. We investigated states with principle quantum numbers between 30 and 50. Our results demonstrate that microcells with a size on the order of the blockade radius, ∼ 2 µm, at temperatures of 100 − 300 • C are robust, promising candidates to investigate low dimensional strongly interacting Rydberg gases, construct quantum gates and build single photon sources.Recently, the mutual interaction between highly excited Rydberg atoms in dense frozen samples has lead to the observation of Rydberg atom excitation blockade [1,2,3]. In Rydberg atom blockade, the excitation of more than one Rydberg atom within a blockade volume is suppressed as the mutual interaction between Rydberg atoms at internuclear separations on the order of micrometers shifts the atomic state out of resonance with a narrow band excitation laser. The corresponding blockade radius, a block , is on the order of several µm for Rydberg states in the range of n= 30 − 50. For example, the 32S state of Rb excited by a 1 MHz bandwidth laser has a block = 2 µm for an ensemble of atoms that do not move on the timescale of excitation [4]. As the huge interaction between individual Rydberg atoms can lead to controlled entanglement of atomic ensembles, Rydberg atom blockade is the basis for several proposals to realize photonic quantum devices, like single photon sources and quantum gates [5,6]. The first promising experimental steps toward this goal using individual well localized pairs of ultracold atoms have been reported [7,8]. Experiments on collective entanglement of ensembles of ultracold atoms have also been performed [1].A technologically interesting alternative approach to ultracold atoms would be to realize Rydberg atom quantum photonic devices in thermal Rb vapor microcells. For this idea, we envision arrays of small blockade sized vapor cells (cavities) etched in glass that can be connected by optical wave guides in a monolithic structure. In such a device, Rydberg atom quantum gates may be realized with mesoscopic ensembles of thermal atoms. Some of the advantages of this approach are the ability to exploit advances in microstructuring technology [9,10,11], the relative simplicity of maintaining and regenerating the sample, the collective enhancement of the laser matter dynamics, and the scalability. We also point out here that a block has a strong scaling with the atomic separation R, proportional to R 6 in the case of Van der Waals interactions. This means that its value for atoms frozen in place only decreases by approximately 2.7 for a thermal distribution of atoms at T = 300 • C, since a block ∝ 6 √ Doppler width.An important point for usin...

Fano resonances and all-optical switching in a resonantly coupled plasmonic–atomic system

“…In addition to the fundamental aspects related to the phenomena of Fano resonance, the interaction of a plasmonic system with atomic vapour such as Rb is very appealing due to the myriad applications that have been demonstrated using alkali vapours in the past decades [42][43][44][45] . Indeed, the community has vast experience in manipulating and controlling such vapours close to room temperature, using both linear and nonlinear interrogation techniques.…”

“…For example, easier probing of surface effects is expected by operating at higher optical frequencies, in the vicinity of the blue portion of the spectrum (for example, at the 5 2 S 1/2 to 6 2 P 3/2 secondary transition at 420 nm). Such operation is anticipated to be of high importance in the investigation of Rydberg 42 states, in the vicinity of metals. Furthermore, understanding the nature of light-matter interactions along metal surfaces may assist the realization of cold atoms chips 21,38,46 in which better understanding of surface interactions is crucial.…”

Phase diagram of Rydberg atoms in a nonequilibrium optical lattice

“…This is a demonstration of the Rydberg blockade phenomenon under strong Rydberg interaction [24]. From experimental view, R ≪ 1.0µm can be realized in solid systems, but it is hard for atoms trapped within a conventional optical lattice [25]. However, subwavelength optical lattices can be facilitated with a recent progress in subwavelength focusing, and have been realized recently for matter wave Bloch oscillation [26].…”

Spatially resolved excitation of Rydberg atoms and surface effects on an atom chip

“…The position and width of the narrow transmission resonance reflect the energy and lifetime of the Rydberg state and provide a sensitive probe of the atom-surface interaction. This is related to a recent experiment investigating Rydberg excitation in a * Atreju.Tauschinsky@uva.nl room-temperature glass vapor cell at very small distances to the walls [28]. Here we investigate the effects of a metallic atom-chip surface with ultracold Rydberg atoms.…”