[ATM] Wavelengths of light

[Dale Eason]

To add a little more info to what Jim Burrows has
already said.  Most test methods like Foucault, Star,
and Ronchi use a broad spectrum and are more geometric
based than wave based tests.  Thus the wavelength used
does not alter the test results. 
 Only Foucault of those tests can give us quantitative
numbers about the surface error and those are in
inches or mm and must be converted into waves of green
if desired.

When testing with an interferometer then one needs to
know the wavelength of the source.  That is then used
to convert the surface error to what ever is of
interest.  The error is usually reported as waves of
green but can also be stated in inches or millimeters.

The reason it is usually converted into waves of green
is that is where our eye is most sensitive and one of
the favorite quality criteria is stated as a fraction
of wavelength.

Dale Eason
--- "Francis J. O'Reilly" <foreilly at verizon.net>
wrote:

> I notice that green, the chosen color for testing
> optics on this list is about in the middle of the
> visible spectrum of light as far as wavelengths go.
> I understand that when we refer to correctiion in
> terms of wavelengths of light we are referring
> generally to wavelengths of green light. Is that
> standard promulgated anywhere? Has anyone here tried
> otehr colors such as purple, a much shorter
> wavelength? Or red a much longer wavelength?
> 
> Just the curious wonderings of a non optical
> professional.
> 
> Francis J. O'Reilly
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 



       
____________________________________________________________________________________
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. 
http://mobile.yahoo.com/go?refer=1GNXIC