1 A.D. Ludlow, X.. Huang, M.. Notcutt, T.. Zanon-Willette, S.M. Foreman, M.M. Boyd, S.. Blatt, and J.. Ye, Optics Letters 32, (2007).
1 X.. Huang, A.B. McCoy, J.. Bowman, L.M. Johnson, C.M. Savage, F.. Dong, and D.J. Nesbitt, Science 311, (2006).