A new ultrathin photodetector captures light across the full spectrum in just 125 picoseconds, opening the door to faster, smarter imaging technologies.
Engineers at Duke University have built the fastest pyroelectric photodetector ever demonstrated, a device that senses light by capturing the heat it produces when absorbed.
This ultrathin sensor can detect light across the entire electromagnetic spectrum. It runs at room temperature, requires no external power, and can be integrated directly into on-chip systems. The technology could lead to a new generation of multispectral cameras with applications in skin cancer detection, food safety inspection, and large-scale agriculture.
Limits of Traditional Light Detection
Most modern digital cameras rely on semiconductor photodetectors, which generate an electrical current when struck by visible light. That signal is then processed into an image.
However, semiconductors are limited to a narrow portion of the electromagnetic spectrum, similar to the human eye. To detect wavelengths beyond that range, researchers often use pyroelectric detectors, which produce electrical signals when they heat up after absorbing light.
These thermal detectors have historically been less effective than semiconductor-based systems. Capturing certain wavelengths requires generating enough heat, which typically demands thick materials or very bright light. As a result, these devices tend to be bulky and slow.
“Commercial pyroelectric detectors aren’t very responsive, so they need a very bright light or very thick absorbers to work, which naturally makes them slow because heat doesn’t move that fast,” said Maiken Mikkelsen, professor of electrical and computer engineering at Duke. “Our approach cleverly integrates near-perfect absorbers and super-thin pyroelectrics to achieve a response time of 125 picoseconds, which is a huge improvement for the field.”
