Prof. Martin Aeschlimann of Kaiserslautern presented the remarkable work by his group using time-resolved 2-photon photoemission microscopy (PEEM) to drive and monitor plasmons on the nanoscale and femtosecond timescale. The technique is a mouthful. It's like electron microscopy, only instead of shooting an electron beam at the sample and looking at the secondary electrons that come out, you illuminate the sample with ultrafast, intense pulses of 800 nm light. If these excite a plasmon mode, then the very intense local electromagnetic field leads to nonlinear two-photon processes that cause photoemission of electrons from the sample, and those photoelectrons are collected by a high resolution electrostatic column similar to that in an electron microscope. The result is, you can "see" plasmons with ~ 10 nm or better spatial resolution, and by varying the time delay between pump and probe optical pulses, you can watch plasmons decay, or transport energy coherently, or interfere with each other. Amazing stuff.
After watching some talks about spin Hall physics (hugely growing activity there, and definitely worth multiple blog posts down the line), I watched a fascinating talk by Scott Kemp of MIT about the Iran nuclear deal - he was one of the US negotiators. It was great to get a sense of the scientific and political reasoning behind the negotiations and their outcome, and there was information in the talk that I hadn't seen anywhere else.
Final thoughts on the meeting:
- The variety of topics and the level of activity in condensed matter physics these days is great to see. It's an active, thriving field, with deep ideas, open questions, and some topics that could well have major technological impact. More than ever, I feel like there is an untapped potential here for informing the public about this stuff.
- The meeting is almost too big at this point. It's unwieldy, and often there are multiple great talks on similar topics scheduled simultaneously. I'm curious to learn what the long-term plans are in terms of meeting (re)organization and abstract sorting. It feels like there has to be a better way to do some of these things, but if there were easy answers they would have been implemented already.
- Finally there was coffee and tea available without making everyone pay through the nose. Whoo-hoo!