A well-lit bridge can be a beautiful thing, and if Princeton researchers have their way, it could also be life-saving.
To be fair, the kind of lighting they're talking about won't affect a cityscape too much. Until it stops a bridge from collapsing, that is.
Electrical engineering professor, Sigurd Wagner, and researcher, Patrick Görrn, are heading up a team working with polydimethylsiloxane (PDMS) - a silicone that molds to any surface imperfections. That, in itself, may not seem so interesting, but the ingenuity is in the tweaks: the team are using specially prepared sheets of it that have a wavy surface covered with organic molecules, which are zapped with an ultraviolet laser.
This is where it gets fun. You see, the laser causes the molecules to emit photons (the basic units of light), and the surface causes the light to diffract, and thus amplify. And then, when something in the bridge cracks or moves, the sheet is distorted, and the color changes! Voila! Time to fix the bridge, building, or other structure it's attached to.
Because nobody wants to see this happen again: