>
"Does anyone here have a ref on how to compare
illumination by coherent light against non-coherent light?

I'm thinking that a laser emitter might do better than my =

existing LED
emitters, but I don't know if the illumination is 1-1 or =

something
different.
We have an existing diode at 500-800mW output covering a =B1 =

60 degree
sweep in both directions, but I would actually prefer some =

compression
in the vertical axis.

/>

Did you really mean OUTPUT.
That's a lot of light.
That would probably be a 5 Watt input unit, no?

With an LED that could be well into eye hazard area =

depending on the wavelength. What colour are you using? With =

a LASER it will certainly be hazardous.

Al commented on 'speckle' from a LASER, which can be an =

issue depending on application. Speckle, whose presence is a =

sure sign of the presence of coherent light, is interference =

troughs and crests occurring on a surface due to the surface =

texture causing slightly differing path lengths. If you have =

speckle it's a LASER source, if you don't have then it may =

be. "Proper" LASERS always produce speckle but diode LASERs =

may do it less as coherence is generally lower due to lack =

of a long 'collimating'* region. If you like the nice =

"furry" 'real LASER' effect then it may be a bonus. If you =

just want illumination then an LED will probably do as well.



            Russell McMahon

* 'collimating' is probably the wrong technical term in this =

context but arguably comes close enough. =


-- =

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