Keith Dysart wrote:
By "NO interference" did you mean "sufficiently close to zero
that it can be ignored for engineering purposes", or "exactly
zero"?

If *mutually incoherent*, then exactly zero, according to
Born and Wolf. "Mutually incoherent" excludes any possibility
of coherency.

If the former, a bit more precision in your writing would be
valuable. The use of CAPITALs certainly suggests the latter.

Note that I didn't say anything about partially coherent
waves or partially incoherent waves. Whether two waves are
coherent or mutually incoherent is indeed a binary situation.
Any middle ground is thus excluded from my statements.

If the latter, how incoherent do the waves have to be before
the interference suddenly drops to ZERO.

I believe mutually incoherent means the same thing as
perfectly incoherent.
--
73, Cecil http://www.w5dxp.com