Imagine being able to see an object hidden around a corner or behind a wall, it sounds like science fiction. Yet this is exactly what our group is working on, using the remarkable power of ultrafast light and advanced computing. In our lab, we’ve built a camera system so fast that it can record the exact time each photon of light arrives, not just where it hits. How fast is it? About a trillion frames per second… fast enough to freeze a beam of light in motion. By capturing this precise timing information, we can reconstruct images in ways conventional cameras cannot, essentially looking beyond the line of sight.
How Does It Work?
The technique works a bit like an optical form of sonar. We start by firing ultrafast laser pulses at a wall or other surface. The light scatters and bounces around a corner, illuminating the hidden scene. A special single-photon detector then catches the faint returning photons that scatter back from the hidden object. Because our system notes when each photon arrives down to the picosecond, we feed this data into algorithms that reconstruct an image of the object that our camera cannot directly see. In essence, the camera “sees” the unseen by timing the echoes of light – much like a bat uses sound echoes to navigate in the dark. Just a few years ago, the idea of looking around corners with a camera seemed “bonkers”, but now we have a lab system that delivers full-colour 3D images of objects hidden from view.
Why Does it Matter?
Such non-line-of-sight imaging has huge potential benefits. Here are just a few exciting applications:
- Safer Transportation: Driver-assist and autonomous vehicles could detect pedestrians or hazards around a blind corner or through fog, giving advanced warning of unseen dangers.
- Search & Rescue: First responders might locate people behind walls or inside collapsed buildings without entering dangerous areas, using lasers to scout for survivors remotely.
- Medical Imaging: The human body is opaque to normal light, but with ultrafast light-in-flight techniques we could see inside the body non-invasively. For example, our group envisions wearable devices to monitor brain activity by imaging blood flow deep in the brain, much like a lightweight optical MRI.
By mastering extreme light, we’re turning science fiction into reality. Every day, our researchers are finding new ways to harness light’s speed and quantum quirks to reveal hidden worlds. From capturing photons in flight to peering behind walls, the group is opening up new forms of imaging that were once unimaginable. It’s a thrilling time for optical science, and we’re just getting started on this journey to see the unseen!