This paper extends and generalizes the principle of Non-Interference of Light (NIL) to diffracted secondary
wavelets. In a previous series of papers we have demonstrated the NIL principle for well defined superposed
light beams, which experience negligible diffracted spreading within the interferometers being used. NIL is consistent
with quantum physics where emitted photons from material dipoles are considered non-interacting Bosons.
Our NIL principle describes the formation of fringes (energy re-distribution) as patterned energy absorptions
or scattering by "local" material dipoles proportional to the square modulus of the sum of all the superposed
stimulating fields experienced by the dipoles.
Any superposition effect as measured (SEM) by us is the summation of simultaneous stimulations
experienced by a detector due to the presence of multiple copies of a detectee each carrying different values
of the same parameter. We discus the cases with light beams carrying same frequency for both diffraction
and multiple beam Fabry-Perot interferometer and also a case where the two superposed light beams carry
different frequencies. Our key argument is that if light really consists of indivisible elementary particle,
photon, then it cannot by itself create superposition effect since the state vector of an elementary particle
cannot carry more than one values of any parameter at the same time. Fortunately, semiclassical model
explains all light induced interactions using quantized atoms and classical EM wave packet. Classical
physics, with its deeper commitment to Reality Ontology, was better prepared to nurture the emergence of
Quantum Mechanics and still can provide guidance to explore nature deeper if we pay careful attention to
successful classical formulations like Huygens-Fresnel diffraction integral.