The paper is authored by M. R. Sprague, P. S. Michelberger, T. F. M. Champion, D. G. England, J. Nunn, X.-M. Jin, W. S. Kolthammer, A. Abdolvand, P. St. J. Russell & I. A. Walmsley . It has been published on the 26th May 2014 on Nature Photonics 8, 287–291 (2014)