Neutron waveguides: A new neutron optical device for the production of submicrometer neutron beams

Planar neutron waveguide structures can be used as resonant beam coupling devices to produce a coherent and divergent neutron line source with cross-sections in the sub-micrometer range. This article reviews our recent work on the theoretical model, the fabrication and the characterization of these devices, demonstrating clearly the good agreement between the theoretical model and the feasability of using neutron waveguides for various applications. As one major result, the farfield-pattern of the first three modes of a neutron waveguide was measured, yielding a 17 times enhanced flux throughput compared to a pair of slits corresponding to the thickness of the guiding layer. Additionally we have generalized the principle of neutron resonant beam coupling to waveguides containing multiple guiding layers, where several beams with a width of the order of 10 to 100 nm can be extracted at the end leading to an typical farfield interference pattern.