17 This technique is known as Off-Axis Digital Holography. See for example: E. Cuche, P. Marquet, and C. Depeursinge, Appl. Optics 38 , 6994 (1999). 18 A. Amo, D. Sanvitto, F.P. Laussy, D. Ballarini, E. del Valle, M. D. Martin, A. Lemaˆıtre, J. Bloch, D. N. Krizhanovskii, M.S. Skolnick, C. Tejedor, and L. Vi˜ na, Nature 457 , 291 (2009). 19 D.N. Krizhanovskii, D.M. Whittaker, R.A. Bradley, K. Guda, D. Sarkar, D. Sanvitto, L. Vina, E. Cerda, P. Santos, K. Biermann, R. Hey, and M. S. Skolnick, Phys. Rev. Lett. 104 , 126402 (2010). 20 D. Bajoni, P. Senellart, E. Wertz, I. Sagnes, A. Miard, A. Lemaˆıtre, and J. Bloch, Phys. Rev. Lett. 100 , 047401 (2008). 8