I propose we run science porn.
Thus spake a site admin, and so I shall. Of course, because of my particular fetish, there’s no porn like AMO porn:
Lab Porn: Plasma! and Lab Porn: Doomsday!
Shoot, a feller could have a pretty good time in Vegas with all that stuff!
AMO Physics meet chips.
I recently had the pleasure of attending a small workshop on the topic of doing atomic physics on chip-scale apparatus. The presentations and discussions were very interesting, but unfortunately do not lend themselves to a blog report for a couple of reasons. This kind of get-together discusses ongoing projects, some or all of which are not-ready-for-primetime, i.e. things haven’t been written up and published, so I wouldn’t be at liberty to discuss details, and a lot of the really cool stuff was shown in the pictures, some of which also haven’t been published. So while I can’t go into certain details, I can give an overview, and provide some links to representative work that has been published or is otherwise available to the public.
There’s quite a bit of physics that is described as being “tabletop” physics — in part to distinguish it from the physics that requires large collaborations and trips to an accelerator lab, or access to a big telescope or a satellite, etc. However, “tabletop” in atomic physics usually refers to an optical table, which can be a behemoth — an 8′ x 4′ table can weigh 1000 lbs or more. Add to that the requisite optics, optomechanics, vacuum systems and the support electronics, and you still have quite a lot of equipment, and it’s not going to be very portable.
As I had mentioned before, research layouts tend to be bigger than they strictly need to be, in order to provide some flexibility, and you can transition to more compact layouts if you have just one application in mind. If you take the concept a little further, and start thinking of the possibility that you might want an AMO experiment (e.g. a MOT or BEC, or trapped ions) to be applied to some specific problem, and require portability, you have to shrink not only the laser system, but the trap, and everything mentioned above — the vacuum pumps, power supplies and control electronics. Fortunately, a lot of this is coupled: if the trapping volume is decreased you don’t need as much pumping capacity or laser power, so your power demand is also smaller. If you can survive the decrease in signal, you can still go pretty good measurements, though new challenges tend to crop up working close to surfaces rather than far away. Instead of using general-purpose power supplies and electronics, you use devices specifically built for the application. You mount components together, rather than spaced apart, and use fibers rather than mirrors to transport light.
The Backyard Arthropod Project
“A Field Guide to the North Side of Old Mill Hill, Atlantic Mine, MI”
Bugs, not in close proximity to me, so I don’t mind so much. Apparently many of them are attracted to or otherwise like to hang out on graph paper. I had no idea…
Much like Google Maps in that there are areas that are not mapped in great detail, and others where you can zoom all the way in (it shouldn’t be all that hard to guess that this correlates with interesting features in the night sky). No “street view” feature, yet.
Chad’s been busy blogging about his recent lab visits to NIST and U. Maryland, and the writeups are, as usual, top-notch. Cavity QED (a subfield I find fascinating and something I might have pursued had the right opportunities arisen when I was looking for a postdoc), Cold Plasmas, Biophysics (you might have a “what the?” reaction, but it uses optical tweezers, which is why this doesn’t really fall under “one of these things is not like the other,” Four-Wave Mixing (another field I find interesting, and the summary is definitely worth a read if you’ve ever wondered if things you learned in QM were ever actually applied to anything. You’ve got electrons moving between states without ever exciting the atom, and squeezed states, which is an exploitation of the Heisenberg Uncertainty Principle)
Last but not least one on this list (so far, anyway) is about trapping Francium. As I mentioned in the U.P. comments, I was a postdoc in the group that tried to trap Francium at TRIUMF several years back, and when we started discussing plans to do it, we were hoping to trap before the Stony Brook lab did so. Well, they succeeded while we … met some obstacles. As I recall, we weren’t the first in line to use the target; there was another experiment that went first, and so we only had a short time to try. And trying to trap something that has no stable isotopes is a special challenge. You have to reference your laser to something, so that you know he frequency of the light you are generating. With an existing stable isotope that’s straightforward, since you can use an absorption line, and the frequency of the radioactive isotope would be close by. Otherwise you do something like locking to an iodine transition, or some other reference cell used in spectroscopy. And you have to know the frequency you want to generate — with no stable or at least naturally-occurring isotopes the spectroscopy information would be very sparse in comparison to other alkalis, so your calculation of where you expect the transition to be has some uncertainties, meaning you have to search frequency-space until you find something. And we ran out of beam time before we saw anything.
And, as I had mentioned, we (well, someone at TRIUMF) got a call from a watchdog station that tries to detect nuclear fallout, wanting to double-check on things. They knew the signature they were reading wasn’t from a bomb, but they knew something was up and guessed our target material: Thorium. When you blast that with energetic protons, you get lots of heavy isotopes.
For a peek at a few more illusions, of the “interchanging 2-D and 3-D” variety, as well as some history & physics behind it all, head on over to Skulls in the Stars.
Of Two Minds discussing Could Superman’s X-Ray Vision Really Exist?
Over at Skulls in the Stars, a good summary of anomalous dispersion (aka pulse reshaping). When a news article reports a laser experiment that supposedly shows superluminal behavior, the odds are pretty good that this is what’s going on.