This article was published on January 7, 2015, but we think it still rocks.
While we're used to seeing laser pathways in fog-filled rooms filled with pounding beats and sweaty dancers, the average Joe normally can't see beyond the red dot at the beam's end—until now. Researchers led by Genevieve Gariepy at Heriot-Watt University have developed a sensor that can detect light at 20 billion frames per second, allowing it to track the path of individual photons as they pass by. The process wasn't easy: they had to fire two million green laser pulses into a group of mirrors, gather each photon's individual data points, and then subtract the background noise using a process similar to the camera that can take pictures around corners. While the resulting footage is actually a visualization of the data, it's the closest anybody has ever gotten to seeing an actual laser flight path.
Visit Genevieve Gariepy's website for more of her work.