Three-port beam splitter for slow neutrons using holographic   nanoparticle-polymer composite diffraction gratings
  Diffraction of slow neutrons by nanoparticle-polymer composite gratings has been observed. By carefully choosing grating parameters such as grating thickness and spacing, a three-port beam splitter operation for cold neutrons - splitting the incident neutron intensity equally into the plus-minus first and zeroth diffraction orders - was realized. As a possible application, a Zernike three-path interferometer is briefly discussed. 
J. Klepp, Y. Tomita, C. Pruner, J. Kohlbrecher, M. Fally
quant-ph cond-mat.mtrl-sci