An epoch in cold neutron interferometry for fundamental physics—development of multilayer interferometer

The development of cold neutron interferometry using multilayer mirrors is reviewed. Our new devices based on etalon plates have made a breakthrough for large-scale multilayer interferometers. In order to obtain much larger area enclosed by the two paths of interferometer, we are developing a Mach–Zehnder type interferometer. To fulfill the severe requirement for aligning the four mirrors, we utilize six solid-etalon-plates coated with multilayer mirrors and a high precision flat base plate.