Date: Mon, 14 Feb 2011 11:14:56

Author: Rueckner, Wolf

Subject: Re: Jello Gradient Index lens modeling the SOFAR sound channel

Post:

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Paul Titcomb and I made a gelatin version of our GRIN demo back in 1981 and=
it worked remarkably well. BTW, you don't need to add a light scattering =
agent to the water. Even clear gelatin scattered quite well. If you smear=
a thin layer of silicone vacuum grease on the walls of your mold, the gela=
tin releases readily (vacuum grease withstands high temperatures). Making =
a SOFAR channel model will be totally cool. My thinking is that, if you ma=
ke a rectangular plastic container w/o a bottom, you could stretch Saran Wr=
ap across it (secured with rubber bands) and have that be the bottom. When=
the gelatin has set, just peal off the Wrap and put the two containers tog=
ether. Then you wouldn't even have to remove the gelatin from the containe=
rs. -- Wolfgang



On Feb 13, 2011, at 8:37 PM, Paul Doherty wrote:

Hi Tap ers

The Exploratorium Explainers are working with NOAA and want to build an opt=
ical model of the undersea sound channel.

I want to build a jello based gradient index (GRIN) optical pathway that wi=
ll trap a laser beam.

I showed them the one where I layer water (doped with milk) over corn syrup=
(doped with milk) and leave it for a day to allow a gradient to form. But =
they want the gradient at both sides of a channel not just at the top.

like this

http://www.fas.harvard.edu/~scidemos/LightOptics/BouncingLightBeam/Bouncing=
LightBeam.html

I found this site on line but the gradient looks a bit too gentle.

http://www.maximizingprogress.org/2010/11/fiber-optic-jello-cooking-up-grin=
-lens.html

Anyone have ideas about or experience making a stronger gradient?

Or do I just make a very long tube of GRIN jello.

Paul D


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http://www.fas.harvard.edu/~scidemos/LightOptics/BouncingLightBeam/Boun=
cingLightBeam.htmlI found this site on line but the gradient lo=
oks a bit too gentle.http://www.maximizingpr=
ogress.org/2010/11/fiber-optic-jello-cooking-up-grin-lens.htmlA=
nyone have ideas about or experience making a stronger gradient?Or =
do I just make a very long tube of GRIN jello.Paul D=

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From tap-l-owner@lists.ncsu.edu Mon Feb 14 11:24:22 2011