Pieter Kok, Hwang Lee, and Jonathan Dowling proposed the first general method based on post-selection via photodetection.
Pryde and White[2] subsequently introduced a simplified method using intensity-symmetric multiport beam splitters, single photon inputs, and either heralded or conditional measurement.
[6][7] Super-resolution has previously been used as indicator of NOON state production, in 2005 Resch et al.[8] showed that it could equally well be prepared by classical interferometry.
They showed that only phase super-sensitivity is an unambiguous indicator of a NOON state; furthermore they introduced criteria for determining if it has been achieved based on the observed visibility and efficiency.
[11] They were independently rediscovered in 2000 by Jonathan P. Dowling's group at JPL, who introduced them as the basis for the concept of quantum lithography.
[12] The term "NOON state" first appeared in print as a footnote in a paper published by Hwang Lee, Pieter Kok, and Jonathan Dowling on quantum metrology,[13] where it was spelled N00N, with zeros instead of Os.