Coherence holography and singular optical coherence

The principle of unconventional holography, called coherence holography, is reviewed with particular emphasis on the formal analogy between an optical field and its coherence function, which gives a clue for developing a new technique for synthesizing singular optical coherence. We present experimental demonstrations of generic coherence vortices generated by coherence holography, and show an experimental evidence of an angular coherence momentum created by coherence currents circulating around the core of the coherence vortex and a conservation law of coherence currents.