Twisted 3D holograms for self-referencing interferometers in metrology   and imaging
  The interference between radiation fields superposed appropriately contains all available information about the source. This will be recapitulated for coherent and incoherent fields. We will further analyze a new kind of twisted 3D interferometer which allows us to generate interferograms with high information content. The physical basis for these devices is the geometric parallel transport of electric fields along a 3D path in space. This concept enables us to build very compact 3D interferometers. 
Martin Berz, Cordelia Berz (IFE Institut f\"ur Forschung und   Entwicklung, Munich/Germany)
physics.optics