Dear Mr. Cecil Moore,

I think now I understand the notation.
If

| ...
| a1*a2 is phasor multiplication, a1*a2*cos(theta)
| ...

then s11*a1*s12*a2
is s11*a1*s12*a2*cos(phi)

which has the same meaning as the

Re{[s11*a1]*Conjg[s12*a2]}

and the only thing which remains
is the specification of the phi range of values.

I think also,
I grasped your point of view
for the existence of a deeper, common, base between
these different physical phenomena,
with which anyone hardly disagrees.

Finally,
I would ask you to tell me please,
the reference details to
Dr. Best's QEX article and Hecht's _Optics_.

Thanking you in advance,

pez
SV7BAX
TheDAG