A one-dimensional ultracold medium of extreme optical depth

摘要

We report on the preparation of a one-dimensional ultracold medium in ahollow-core photonic crystal fiber, reaching an effective optical depth of1000(150). We achieved this extreme optical depth by transferring atoms from amagneto-optical trap into a far-detuned optical dipole trap inside thehollow-core fiber, yielding up to 2.5(3)$\times$10$^5$ atoms inside the corewith a loading efficiency of $2.5(6)~\%$. The preparation of an ultracoldmedium of such huge optical depth paves the way towards new applications inquantum optics and nonlinear optics.