Scientists Build Fastest Photodetector Ever, Sensing Light in 125 Picoseconds

Researchers at Duke University have built the fastest pyroelectric photodetector ever created, a device so quick it can sense light across the entire electromagnetic spectrum and generate a signal in just 125 picoseconds.

To put that speed in perspective, 125 picoseconds is 125 trillionths of a second, roughly the time it takes light to travel about an inch and a half. The achievement represents a significant leap forward in detector technology with potential applications spanning communications, medical imaging, and scientific instrumentation.

The device is built from an ultrathin material that responds to incoming light by generating heat, which in turn produces an electrical signal. What makes this detector remarkable is not just its speed but its breadth. Unlike most fast detectors that work only within narrow wavelength ranges, this one responds to light from across the electromagnetic spectrum, from ultraviolet through visible light to infrared.

That versatility matters because different applications require sensitivity to different types of light. Telecommunications systems use infrared, medical scanners might use various wavelengths, and scientific instruments often need to detect across multiple bands simultaneously. A single detector that handles all of these could simplify system designs considerably.

The research team achieved this performance by carefully engineering the thickness and composition of the sensing material. Thinner materials heat up and cool down faster, enabling quicker response times, but they also absorb less light, making the signal weaker. The Duke team found a balance point that maintains usable signal strength while pushing response times into territory previously thought impossible for this type of detector.

Pyroelectric detectors have traditionally been valued for their ability to work without external cooling, unlike many high-speed alternatives that require cryogenic temperatures. This new device maintains that room-temperature advantage while dramatically closing the speed gap with cooled detectors.

The breakthrough could prove particularly valuable in next-generation optical communications systems, where data rates continue to climb and detector speed is increasingly the limiting factor in system performance.