New Photodetector Could Improve Medical Imaging, Thermal Sensing
The device is sensitive and speedy, and works with many types of light.
Using graphene, researchers have developed a new type of photodetector that operates across a broader range of light than current technology. The new photodetector also processes images more quickly and is more sensitive to low levels of light than other devices.
Photodetectors are the components of cameras and other imaging devices that sense light. The new photodetector, described in the journal Light: Science and Applications, uses graphene, a material with unique electrical and optical properties that enables simultaneous broadband and ultrafast photodetection with high responsivity.
To create the photodetector, the researchers laid strips of graphene over a silicon dioxide layer atop a silicon base. They added a series of comblike nanoscale patterns made of gold. The graphene catches incoming light particles called photons and converts them into an electrical signal. Then the gold nanoscale patterns transfer that information into a processor, which produces a corresponding high-quality image even under low-light conditions.
With their device, the researchers demonstrated high-responsivity photodetection from the visible to the infrared ends of the light spectrum. The photodetector also had response times that were more than seven orders of magnitude faster and bandwidths that were one order of magnitude broader compared to other graphene photodetectors.
The new photodetector has several potential applications. It could be used to improve thermal imaging in night vision cameras and medical imaging devices or to identify the concentration of pollutants via environmental sensing technologies.