Holography with a neutron interferometer

We demonstrate the first neutron hologram of a macroscopic object.\footnote{D. Sarenac, {\em et al.}, Optics Express {\bf 24}, 22528 (2016).} Using a Mach-Zehnder neutron interferometer in a configuration similar to the optical setup of Bazhenov {\em et al.},\footnote{V. Y. Bazhenov, M. V. Vasnetsov, and M. S. Soskin, Pis’ma Zh. Eks. Teor. Fiz. {\bf 52}, 1037 (1990).} our reference beam passes through a fused silica prism that provides a linear phase gradient, and our object beam beam passes through an aluminum spiral phase plate with a topological charge of $\ell = 2$, which was recently used in studies of neutron orbital angular momentum.\footnote{C. W. Clark, {\em et al.}, Nature {\bf 525}, 504 (2015).} Interference of reference and object beams in a two-dimensional imaging detector produces the hologram, which is a fork dislocation structure similar to those used to generate atomic\footnote{ H. He, {\em et al.}, J. Mod. Opt. {\bf 42}, 217 (1995).}$^,$\footnote{M. F. Andersen, {\em et al.}, Phys. Rev. Lett. {\bf 97}, 170406 (2006).} and electronic\footnote{B. J. McMorran, {\em et al.}, Science {\bf 331}, 192 (2011).} vortex beams. Our neutron hologram is made in an interferometer in which at most one neutron is present at any given time.