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Old March 11th 04, 05:47 PM
Cecil Moore
 
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Walter Maxwell wrote:
Cecil, your equations for P1 and P2 yield absurd answers if you plug the numbers
into them. The value for P1 should read "Psource (1 - rho^2) = ..., and the
value for P2 should read "P2 = Pref (rho^2). Beega difference! Then the value
for Ptotal will be correct.


Yep, Walt, I made a typo. It should be (1-rho^2). When I think in words while
typing, "one minus rho squared", is ambiguous. Obviously (rho)^2 + (1-rho^2)
*must* equal unity, i.e. the total.

I'm glad you find that Chapter 23 fits, because I've known all along that it
fits perfectly with Melles-Griot. Steve (Best), on the other hand says Chapter
23 is totally wrong.


I don't know how he can say that. The Melles-Griot data for perfect non-glare
glass depends upon two 'I' irradiance equations.

Irradiance toward the source (reflected irradiance) equals:

Ir1 + Ir2 - 2*(Ir1*Ir2) = 0 = Ir1 + Ir2 - total_destructive_interference

Irradiance toward the load (total forward irradiance) equals:

If1 + If2 + 2*(If1*If2) = If1 + If2 + total_constructive_interference

It may not be apparent but (Ir1*Ir2) *must* equal (If1*If2).

Steve and I had an argument about this stuff years ago before he published his
QEX article. He denied that any interference exists even though his 2*SQRT(P1*P2)
term is know as the "interference term".

Irradiance, 'I', for a laser beam, is equivalent to power. Reflectance, 'R' in optics, is
the power reflection coefficient. Transmittance, 'T' in optics, is the power transmission
coefficient. Thus:

Ir1 = R*Isource Ir2 = T*Iref If1 = T*Isource If2 = R*Iref

You might find Slater (1943) difficult to obtain. I can email you a copy of the
pertinent part if you wish.


Thanks, but my used copy has already shipped through http://www.powellsbooks.com

Walt, as you know, QEX refused to publish my rebuttal of Steve's article. There's
some good stuff and some bad stuff in his article. This is not a black and white
argument. IMO, about a third of Steve's Part 3 article is valid. My objections
are with the other 2/3.
--
73, Cecil http://www.qsl.net/w5dxp



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