In optical signal processing, the implementation of quantum holography has advance considerably since the last few years. Specifically micro-optical devices such as 2D planar arrays of diffractive microlenses have recently received considerably attention in the optics R & D community. In this paper it is established that the symmetries as expressed by the non- split central group extensions... of quantum holography represent the unified mathematical approach to confocal scanning microscopy by planar point arrays, micro-optics layers of diffractive circular-grating laser structures, resonant components, nuclear magnetic resonance imaging including echo-planar imaging and functional magnetic resonance imaging and nuclear magnetic resonance microscopy.
"Quantum holography and magnetic resonance imaging", Proc. SPIE 2398, Circular-Grating Light-Emitting Sources, (10 April 1995); doi: 10.1117/12.206345; https://doi.org/10.1117/12.206345