@phdthesis{oai:oist.repo.nii.ac.jp:00001047,
 author = {Nieddu, Thomas},
 month = {2020-07-31},
 note = {Optical nanofibers (ONFs) interfaced with atoms have found numerous applications for the development of quantum technologies. They feature a strong evanescent held at their waist, thereby providing an intense and tightly focused beam over long distances. This
can be used to achieve strong interactions between light and matter, enabling trapping, probing, and control of atoms along the waist. However, little experimental work has been done with the higher-order fiber guided modes (HOM). These feature inhomogeneous polarization distributions around the waist and some carry more than h of angular momentum (AM). Owing to the intense held gradient in their evanescent held, ONFs make excellent platforms to excite quadrupole-allowed transitions which could be used to store high-density information encoded on the AM of guided light. We predicted a transition probability up to 6 times stronger than for free-space beams using the fundamental mode and up to 4 times stronger using linearly polarized HOMs. We also studied a singlecolor, two-photon transition at 993 nm between the 5SI/2 and 6S1/2 atomic levels in a hot rubidium vapor and showed its suitability as a frequency reference. We experimentally verihed the particular selection rules for this transition and showed that they may be used to characterize the polarization at the waist of an ONF embedded in a cloud of atoms formed by a magneto-optical trap. Finally, we developed a method to generate HOM-like
beams in free-space, inject them into an ONF, and decompose the modal excitation at the output via transfer matrix calculation. This approach combined with absorption of guided-light by cold atoms may be used to infer the mode excitation at the waist and allow us to selectively excite HOMs.},
 school = {Okinawa Institute of Science and Technology Graduate University},
 title = {多光子過程とルビジウムとの選択モード相互作用の為の光ナノファイバー},
 year = {}
}