Lighting Up Your Quantum Class

I forgot to tell you about this last week, so here goes. The colloquium last week was given by John O’Brien. One of the perks of the job of having to organize the department’s colloquium series is that you can use it (on rare occassions) as a blunt tool to find things out. I’ve always been curious about connecting the name I saw on one of the labs downstairs to a face. John’s lab, primarily part of the Engineering department, uses a little of the space in our building, you see, but I’ve never really made the connection between the face and the name. It certainly seemed that the USC Center for Photonics, of which he is part, was certainly up to some interesting and fun stuff, and so, egged on by another curious colleague, I sent him an invitation to give us a colloquium. He generously accepted, and here he is:

The talk -see the abstract here– was excellent. As you can see from the website listing the faculty in the centre, they are concerned with all sorts of fun things to do with very small scale devices which do rather clever things with light, such as nanoscale semiconductor lasers. The reason that the talk was excellent, in my opinion, was because it was not a standard device+engineering talk that you can often get from very good engineers who nevertheless don’t neccessarily appreciate what aspects the physicists care about. Those talks can often be pretty pictures and so forth of… well… lots of cool toys, without a sense of the physics that is going on. John took a different tack and grabbed our attention by starting out with the phsysics problems right at the outset…. reminding us of those condensed matter physics courses we all took as students, and then pushing us along to appreciate what he was doing with that physics, building up the complexity of the devices as he went. This is the way to do it.

Another reason I liked it was one of nostalgia. I think I might have been one of the last generations of undergraduates where, in your quantum mechanics class, the whole business of infinite square well one-dimensional potentials and other such simple model systems was really just the stuff of textbooks and “of course that does not really happen in the real world”. Just about the time I was learning about those systems in the middle to late 80s was about when the fabrication technology was getting to the point when they were beginning to actually make those cutely simple systems in the lab. Those back of the envelope computations (as they because once you got good at them) really became the stuff of the real world, and not just toy models. By now, almost a couple of decades later, it’s pretty routine, and you can fabricate these devices in any modern kitchen. (Ok, that last piece of the sentence after the second comma is an overstatement made by the G+T that sits at my side, but you get the idea.)

Our shockingly excellent librarian, Sara Tompson, who actually attends many of our physics colloquiua (the stuff of dreams, eh?) has constructed a webpage with more information about the talk’s contents in the form of a bibliography. She’ll be doing that for many more of the colloquium talks, and so I’ll often point to this excellent resource in posts like this. John says he may send me a pdf of his slides, which I’ll link to in an update if he does.

-cvj