Transmission of a dark hollow beam by hollow-core anti-resonant fiber

Transmission of dark hollow beams is crucial for blue-detuned guiding of cold atoms, which is fundamental for cold-atom interferometers. We propose an anti-resonant hollow-core fiber and successfully demonstrate ∼13-cm guiding of a dark hollow beam. The intensity profile of the dark hollow beam can be well maintained during transmission through the hollow-core fiber, which is necessary and important for the high-quality guiding of cold atoms. A large fiber core of ∼40-μm diameter facilitate high coupling efficiencies of cold atoms. Moreover, the hollow-core fiber has such a simple structure that fabrication becomes very easy.