Saturated and near-diffraction-limited operation of an XUV laser at 23.6 nm by Carillon, A, Chen, H, Dhez, P, Dwivedi, L, Jacoby, J, Jaegle, P, Jamelot, G, Zhang, J, Key, M, Kidd, A, Klisnick, A, Kodama, R, Krishnan, J, Lewis, C, Neely, D, Norreys, P, O'Neill, D, Pert, G, Ramsden, SA, Raucourt, J, Tallents, G, Uhomoibhi, J