All-optical production and trapping of metastable noble-gas atoms down to the single-atom regimeM. Kohler, H. Daerr, P. Sahling, C. Sieveke, N. Jerschabek, M. B. Kalinowski, C. Becker and K. SengstockEPL, 108 1 (2014) 13001DOI: https://doi.org/10.1209/0295-5075/108/13001