The real part of the refractive index is very nearly 1.0 for every material at that energy. Eberhard realized that the imaginary part (i.e. the loss) varied much more and could also be used to make thin film mirrors.
IIRC he used a lot of thin layers of metal, alternating with much thinner layers of carbon.
Cheers
Phil Hobbs
So I've been thinking about opamp current noise. And looking at the noise plot for the opa134 pg 4 here.
The current knee is not near the 12kHz number I calculated above. but ~2.5-3kHz. ~4 times worse, a capacitance of 20 pF!
So if picking a new photodiode opamp I should pay attention to the current noise plot too?
You know I think I measured this 20pF number. (Zero current noise in a PD TIA.)
George H.
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