Wow! Today was absolutely packed and quite exciting. First off I just invented my "Most Amusing Talk" award so I could give it to John Dudley, whose talk (slides available here) was very entertaining. He started off with a case of how he was wrong, then moved into a recount of how he was observing super continuum generation (where you get white light from almost single color laser light using special optical fibers) as a solution to the nonlinear wave equation and couldn't get it published anywhere (Science, Nature, and on down the food chain), but eventually got it into Applied Optics. Now these types of results make the cover of Nature Photonics! He suggested they start the journal "Nature Reinterpretations" which got a good chuckle from the audience.
This was mixed with a recount of how the first nuclear weapon design (gun type) was not actually tested, but the engineers who were building it had a good idea it would work, so while the physicists were busy testing their bomb (implosion type), the engineers just dropped theirs! I really have no idea how this fit in, but interesting trivia anyway. Another good quote; "Fluid dynamicists were divided into engineers who observed things that could not be explained and mathematicians who explained things that could not be observed …" (Sir James Lighthill). I can think of some other fields, where this is true.
Finally, he ended by showing just why science is exciting - the solutions they were seeing in their nonlinear optics experiments should have been possible in water (where the equations the optics people used were first developed). Despite searching, no-one had been able to produce the effect in water until the optics folks showed the way. And now we have rogue wave type solitons in water;
The best part of the day, however, was going by the '"Mission: Optical" Student Chapter Competition'. The goal was to build a project for under $25 (US) that demonstrated an optics principle. So many good and fun ideas - I'll definitely be stealing many of these! My favorites were a balloon stretched across the end of a tin can, the other end was cut off so you could speak into it. A laser pointer was then attached pointing at a mirror (or CD) that was glued to the balloon. When you spoke into it, the balloon drum would vibrate, and the reflected spot would trace out a pattern on the wall. A great way of 'visualizing sound', and much easier, more direct and more robust than having motors drive mirrors to deflect the laser beam. Another group used legos, LED's, CD's and some ingenuity to build a 3D stroboscopic viewer. It almost worked. But it was enough of an ingenious idea, that I'd really like to give them credit for it.
Other groups used just a bucket of water, sugar and milk to demonstrate as many different optical principles as they could: Reflection and refraction, the later of which changes with the addition of sugar to the water, total internal reflection in the bucket and the addition of milk for scattering. And another had a great setup that really made it easy for students to get into the scientific principle (just don't tell the kids that). They had kids split into groups and try different ways to heat water. Yet another demonstration of just why I think these conferences are awesome - I never would have thought of some of these ideas on my own, but now I can use them to teach others about optics.
