The first neutron interferometer built of holographic gratings

Abstract

Holographic gratings in thick slabs of photosensitised poly(methyl methacrylate) are produced by illumination with UV interference fringes. The resulting modulation of neutron scattering length density makes the gratings act as neutron beam splitters, a diffraction efficiency eta > 70% of the incident neutrons was achieved. An LLL-interferometer was built of three such highly efficient gratings, which had been adjusted during their recording once for ever. The successful test with cold neutrons (lambda = 1.5 nm) revealed a degree of coherence of gamma approximate to 0.7.