Λ -Enhanced Gray-Molasses Loading and EIT Cooling of Neutral Atoms in Nanophotonic Traps
Year: 2026
Type: article
Abstract: Nanophotonic traps for cold atoms typically have trap volumes that are orders of magnitude smaller than, e.g., free-space optical tweezers. This makes efficient loading of these traps challenging, thereby limiting the total number of atoms coupled to the nanophotonic waveguide. Here, we demonstrate that Λ -enhanced gray-molasses ( Λ GM ) can substantially increase the number of trapped atoms in a nanofiber-based cold-atom setup. Specifically, we observe a sixfold increase in the number of loaded atoms compared to conventional red-detuned polarization-gradient cooling. Despite the unusually small depth of our optical trap of only 24 μ K , we load about 4000 individual cesium atoms, achieving optical depths exceeding 140 and reaching the collisional blockade regime over a length of approximately 1 mm. After loading, we perform efficient electromagnetically induced transparency (EIT)-assisted cooling that is found to increase the trap storage time to 400(9) ms. This is a fivefold improvement over the passive storage time. Remarkably, we observe that EIT-cooling also works with two co-propagating nanofiber-guided light fields and requires only a few hundred picowatts of optical power. Our results provide an efficient method to boost both the number of loaded atoms and the storage time of nanophotonic atom traps.
Source: PRX Quantum
DOI: 10.1103/5l6x-4377
Institution: Humboldt-Universität zu Berlin
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,450
OpenAlex ID: W7211948073