<s>
In	O
optics	B-Algorithm
,	O
the	O
Ewald	B-Algorithm
–	I-Algorithm
Oseen	I-Algorithm
extinction	I-Algorithm
theorem	I-Algorithm
,	O
sometimes	O
referred	O
to	O
as	O
just	O
the	O
extinction	B-Algorithm
theorem	I-Algorithm
,	O
is	O
a	O
theorem	O
that	O
underlies	O
the	O
common	O
understanding	O
of	O
scattering	O
(	O
as	O
well	O
as	O
refraction	O
,	O
reflection	O
,	O
and	O
diffraction	O
)	O
.	O
</s>
<s>
An	O
important	O
part	O
of	O
optical	O
physics	O
theory	O
is	O
starting	O
with	O
microscopic	O
physics	O
—	O
the	O
behavior	O
of	O
atoms	O
and	O
electrons	O
—	O
and	O
using	O
it	O
to	O
derive	O
the	O
familiar	O
,	O
macroscopic	O
,	O
laws	O
of	O
optics	B-Algorithm
.	O
</s>
<s>
The	O
Ewald	B-Algorithm
–	I-Algorithm
Oseen	I-Algorithm
extinction	I-Algorithm
theorem	I-Algorithm
is	O
one	O
part	O
of	O
that	O
derivation	O
(	O
as	O
is	O
the	O
Lorentz	O
–	O
Lorenz	O
equation	O
etc	O
.	O
</s>
<s>
The	O
Ewald	B-Algorithm
–	I-Algorithm
Oseen	I-Algorithm
extinction	I-Algorithm
theorem	I-Algorithm
says	O
that	O
the	O
light	O
emitted	O
by	O
the	O
atoms	O
has	O
a	O
component	O
traveling	O
at	O
the	O
speed	O
of	O
light	O
in	O
vacuum	O
,	O
which	O
exactly	O
cancels	O
out	O
(	O
"	O
extinguishes	O
"	O
)	O
the	O
original	O
light	O
wave	O
.	O
</s>
<s>
Altogether	O
,	O
the	O
only	O
wave	O
in	O
the	O
glass	O
is	O
the	O
slow	O
wave	O
,	O
consistent	O
with	O
what	O
we	O
expect	O
from	O
basic	O
optics	B-Algorithm
.	O
</s>
<s>
A	O
more	O
complete	O
description	O
can	O
be	O
found	O
in	O
Classical	O
Optics	B-Algorithm
and	O
its	O
Applications	O
,	O
by	O
Masud	O
Mansuripur	O
.	O
</s>
<s>
A	O
proof	O
of	O
the	O
classical	O
theorem	O
can	O
be	O
found	O
in	O
Principles	O
of	O
Optics	B-Algorithm
,	O
by	O
Born	O
and	O
Wolf.	O
,	O
and	O
that	O
of	O
its	O
extension	O
has	O
been	O
presented	O
by	O
Akhlesh	O
Lakhtakia	O
.	O
</s>
<s>
The	O
Ewald	B-Algorithm
–	I-Algorithm
Oseen	I-Algorithm
extinction	I-Algorithm
theorem	I-Algorithm
seek	O
to	O
address	O
the	O
disconnect	O
by	O
demonstrating	O
how	O
the	O
superposition	O
of	O
these	O
two	O
waves	O
reproduces	O
the	O
familiar	O
result	O
of	O
a	O
wave	O
that	O
moves	O
at	O
a	O
speed	O
of	O
c/n	O
.	O
</s>
