| 研究実績の概要 |
We created a hybrid quantum system consisting of cold Rydberg atoms and an optical nanofiber interface. Using a two-photon ladder-type excitation in
Rb-87, we demonstrated both coherent and incoherent Rydberg excitation at submicron distances from the nanofiber surface. The 780-nm photon, near resonant to the 5S → 5P transition, was mediated by the cooling laser, while the 482-nm light, near resonant to the 5P → 29D transition, was mediated by the guided mode of the nanofiber. The population loss rate of the cold atom ensemble was used to measure the Rydberg population rate. A theoretical model was developed to interpret the results and link the population loss rate to the experimentally measured, effective Rabi frequency of the process.
We also continued our theory collaborative work in relation to spontaneous emission of a Rydberg atom close to an optical nanofibre. Here, the collaborators have developed a tool-box that we can use to determine the rate of spontaneous emission as a function of distance from the nanofibre, the fibre's radius and the symmetry of the Rydberg state. This work is crucial for facilitating the experimental work that we are doing and assists us in experimental parameter selection.
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| 今後の研究の推進方策 |
During the next phase, we have implemented atom trapping next to the optical nanofibre and will do the Rydberg excitation on the trapped atoms in order to determine a more precise estimate of the atom-fibre surface. If this excitation scheme seems inefficient, we will instigate an optical tweezers style trap next to the nanofibre and use the nanofibre itself for the excitation (as with our ealier published work). This will allow us to control position of the atoms relative to each other and a study on the Rydberg blockade effect next to the optical nanofibre.
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