Imaging the speed of light
Nothing is faster than light, yet we managed to see light travel millimeter by millimeter with a one-trillion-frames-per-second ultra high speed video camera build from a femto second laser and a streak camera. The imaging technique, devised by MIT researcher Raskar, can have impact in applications such as diffuse optical imaging or 3D surface imaging.
Below the camera films with a picosecond time resolution how a femto second laser pulse passes through a strongly scattering polyoxymethylene sample as function of time. It shows the principle of the time-of-flight imaging approach: light that arrives first has travelled straight through the phantom, while light that arrives later has scattered and therefore exits delayed and at different positions. The movie clearly shows that the position and size of the SS cylinders are seen much more clear in the first 10 or 100 ps compared to longer time slots or continuous wave illumination.
Picosecond time-of-flight camera: 3D surface imaging
Nothing is faster than light, yet we managed to see light travel millimeter by millimeter with a one-trillion-frames-per-second ultra high speed video camera build from a femto second laser and a streak camera. The imaging technique, devised by MIT researcher Raskar, can be applied as a time-of-flight camera to do 3D surface imaging. Below the camera films with a picosecond time resolution how a femto second laser pulse (in the form of a expanding spherical shell) passes over a my face. A z-coordinate can be added to the xy-data by making use of the time resolved data.
