Re: [ATM]: What do they offer:

[Stan Truitt <s.truitt@verizon.net>]

Aloha Mark,


>a laser diode
>with the current backed off to just below the lasing threshold makes a
>very bright and compact source.  Maybe bright enough for two bounces off
>of uncoated glass?

Maybe.  The next time a lamp replacement is needed, such a diode 
setup would be fun to test!  Do you have any specific devices and 
current ranges to try?


>I know making coherence requires quantum mechanical magic.

No, the means and techniques for the establishment of stable TEM 
zero-zero oscillation modes have been demonstrated, optically, since 
the early 1960s.  Wasn't it Arthur C. Clarke that said:
[Any sufficiently advanced technology is indistinguishable from magic.]
Perhaps, in this specific regard, haven't we already arrived? 
Redefined this "magic"?


>I wouldn't
>think destroying it should be so hard.  How about a bit of microscope
>slide finely ground on both sides followed by a condenser lens?

Clearly, the destruction of coherence is not "so" difficult!  What is 
problematic, is the suffering of enormous brightness loss from 
scattering that energy into 4pi steradians, (TWICE!), and efficiently 
re-imaging it into the tiny numerical aperture represented by our 
typical (or even advanced) amateur test layouts.  Further 
complications would arise from solid angular variations in intensity 
within the condenser's output cone, and as much of our 
non-interferometric testing is intensity based, this could easily 
complicate or corrupt the test data.

Like I said:
>  Tungsten ribbon lamps are a practical necessity <
Emphasis on "practical"!


Thanks for your input,

Stan Truitt
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