Researchers are developing a new technique for imaging through a single multimode optical fiber the width of a human hair. The researchers aim to create a new generation of single-fiber imaging devices that can produce 3D images of remote scenes.
Normally, when light shines through a single multimode optical fiber, crosstalk between modes scrambles the light to make the image unrecognizable. To resolve this, the team uses advanced beam shaping techniques to pattern the input laser light to the fiber to create a single spot at the output. That spot of light then scans over the scene and the system measures the intensity of the backscattered light into another fiber—giving the brightness of each pixel in the image.
By using a pulsed laser, they also measure the time of flight of the light and hence the range of every pixel in the image. These 3D images can be recorded at distances from a few tens of millimeters to several meters away from the fiber end with millimetric distance resolution and frame rates high enough to perceive motion at close to video quality.
The technique could transform imaging for a wide range of applications in industrial inspection and environmental monitoring. In the longer term it could be further developed for applications in medical imaging.