Streetlights on the Seine

This should have been Friday's post, but I was too sleepy to write yesterday.  Work went quite well - a new sample of cavities has been finished, and I got to test some of the Fabry-Perot cavities.  Each microcavity is a layer of polymer doped with lasing dye molecules, on a substrate of polished silicon.  There are maybe twenty cavities per sample, at least among the samples I've seen, and the cavities can range from several sizes of Fabry-Perot, to square or stadium-shaped cavities.

I'm still just poking around looking at the variance in individual line widths in Fabry-Perot spectra, but at least the new sample seems to have much more consistent widths.  I'm hoping that maybe some of the other properties that weren't displaying a trend with the old samples will prove less mystifying now.  Additionally, I'm trying to look at line widths for squares and stadiums, but I'm having trouble getting them to lase nicely and I'm not sure why.

This new sample is pretty nice.  It's got Fabry-Perot cavities of equal width but varying lengths, so we can check what that does to line width.  (My prediction: nothing.  Some of last week's data suggests that too.)  I think it's also supposed to have F-P's with nonparallel sides.  I got to go with Melanie to look at the sample in the clean room under the microscope, which was interesting.

In the evening, Kierstin, Mir, Margaret, and I found a park in the north-east of Paris called Buttes Chaumont.  The pictures of it on the internet looked very pretty and dramatic, featuring a lake with a tall, rocky island in the middle.  As it turned out, the park was very nice...even if all the rocks were made of concrete.  I'm not sure why that was the case; at times I felt a bit as though I were inside a zoo exhibit.  But the rocky island afforded some nice views of the surrounding area.

When we were finished with the park, Mir and Kierstin headed back to the dorms, but Margaret and I left the RER at the Chatelet station and just walked around for a while.  The rain and the streetlights made for an enjoyably different atmosphere.  The lights on the Seine, the reflections from rainy cobbled streets, the relative lack of crowds - it was a quiet personal sort of Paris experience.  And I bought and ate a delicious sugared crepe, after watching the vendor make it on a huge circular griddle in front of me.

We ended up at Notre Dame.  Wherever I start in this city, I seem to end at Notre Dame.