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| Phil Hobbs... |
 Posted: Wed Oct 07, 2009 2:47 pm |
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AES wrote:
[quote:87b5701dda]Packed MgO powder is significantly better than Spectralon, and quite a bit
cheaper. Of course it doesn't work as well on the top of the integrating
sphere....
You're bringing back half-century-old memories of packing MgO into the
annular space between two concentric lengths of glass tubing, then
standing that structure on end and pounding the lower end on a stone
optical table, or leaving it for while on a vertical shake table, to
densify the powder, leading eventually to a diffuse pump cavity for a
spiral flashlamp pumped ruby laser.
(My intuition was all against this approach -- I was sure that no matter
how tightly the powder was packed, light would scatter down into the
interstices in the power, and ultimately get absorbed before it ever got
scattered back to the surface. Fortunately others knew better.)
[/quote:87b5701dda]
Cool.
White surfaces are actually a 3-D version of the Gambler's Ruin problem
of probability--it becomes exponentially unlikely to avoid hitting the
boundary (or hitting zero $) as the number of trials goes up.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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