Re: Fresnel Lens

[brian whatcott <inet@INTELLISYS.NET>]

At 00:15 4/15/00 -0700, Leigh wrote:
> ....[?] Fresnel lenses are figured to within a
> wavelength of light or fraction thereof. That is not the case.
> M. Fresnel invented these devices to collimate lighthouse beacons,
> not to make high resolution optical images, and they don't.
> Leigh

There is one Fresnel-like lens that has not yet caught the
imagination of engineers who specify such things.
   This application *does* require precision at the wavelength
level.

 It's the hologram lens. In general it's fit for monochromatic
applications.
It could replace expensive glass lenses and with its light weight
 and general portability, it would be so much more testable than
glass as to obviate embarrassments of the Galilean kind.



brian whatcott <inet@intellisys.net>
Altus OK