H2020Индивидуална стипендия2015–2017

NanoBragg · Nanofiber-based atomic Bragg structures

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2015-09-01 → 2017-08-31
Финансиране от ЕС: 178 157 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Оптични нановолокна с уловени в тях лазерно охладени атоми се използват за създаване на атомни огледала, които отразяват светлината. Тези структури помагат за подобряване на квантовите памети и обработката на информация.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Nanofiber-based atomic Bragg structures

In recent years, first devices that harness the effects of quantum physics for improved metrology and information processing have been succesfully commercialized, and multinational corporations have committed significant resources to quantum research. The technologies and methods employed are as diverse as potential applications. For optical quantum information processing, technologies based on optical fibers are particularly attractive, because they promise simple interconnection. At the TU Wien, we investigate quantum interfaces based on arrays of laser-cooled atoms coupled to the evanescent field of light that is efficiently guided in the waist of a tapered optical fiber. The waist diameter is only few hundred nanometers. These nanofiber-trapped atoms are extremely promising for quantum information processing and communication. The aim of this project was to begin the development of specialized nanofiber protocols that take advantage of the unique properties of this system by tuning the periodicity of the atomic array into Bragg resonance. The scattering of light by the atoms is then enhanced by coherent collective effects leading, for example, to atomic Bragg mirrors where an ensemble of only few thousand atoms reflects close to 100% of fiber-guided light. Before the start of the project we conjectured that specialized nanofiber protocols would enable radically new approaches for optical quantum information processing, and Bragg structures would be a first step in this direction. An extraordinary example that this conjecture was correct was given by theoretical work unrelated to this project by A. Asenjo-Garcia et al. (Phys. Rev. X 7, 031024, August 2017), who showed that exponential improvements for optical quantum memories can be achieved. The objectives of the project were the experimental realization and investigation of an atomic Bragg structure in the vicinity of an optical nanofiber. While this objective could not be achieved during the funding period due to unforeseen experimental difficulties, an experimental apparatus with a record-high number of nanofiber-trapped atoms was realized, and results for collective scattering into a free-space Bragg resonance are imminent. In addition, symmetry-breaking lateral forces on the atoms arising during spontaneous emission were studied theoretically, and novel means to probe and manipulate the motional state of the atoms with the help of the particular polarization properties of nanofiber-guided light were realized.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

In this proposal, we want to create an atomic Bragg structure by carefully adjusting the inter-atomic spacing between nanofiber-trapped atoms to approach a Bragg resonance. The structure allows to engineer the atom-nanofiber coupling for quantum-information applications. We hence build on the recent rapid progress of a novel light-matter interface based on an atomic ensemble trapped in an optical lattice created by the evanescent field of nanofiber-guided light. The small effective area of the evanescently guided light field results in a large optical depth per atom on the few-percent level. The number of atoms can easily reach several thousands for nanofibers with a length of few millimeres. In combination with the proven coherence properties, it is an ideal candidate for the implementation of fundamental building blocks for quantum information processing (QIP), such as efficient fiber-integrated quantum memories for light and optical nonlinearities on the few-photon level. However, in view of recent discoveries related to the coupling between polarization and propagation direction of the nanofiber modes, we believe that the true potential of the nanofiber system can only be unleashed by developing specialized protocols. Those protocols need to take the extraordinary polarization properties of the nanofiber-guided modes and the multilevel structure of the atoms into account. Specialized protocols will benefit from the enhanced coupling of the atoms to the nanofiber provided by the Bragg structure. We will characterize the transmission and reflection properties of the nanofiber-coupled atomic Bragg structure, with special attention to polarization effects. Subsequently we will demonstrate how the Bragg resonance can be used to enhance the spontaneous emission of the atomic array into nanofiber-guides modes with a desired propagation direction and how this significantly improves the success rate of the DLCZ quantum memory protocol.

Оригинален текст от CORDIS (на английски).

Участници

TECHNISCHE UNIVERSITAET WIEN · WienКоординаторАвстрия