A Hologram from a Speckle of Light express
Shine a flashlight through rough glass, and the wall lights up with a speckled pattern of bright and dark dots. Once dismissed as useless noise, this pattern now serves as the key to reconstructing 3D images.
In the new system, light from an object passes through a specially designed plate with known irregularities. The plate mixes the rays, creating a speckle pattern, like the dappled shadow of leaves on the ground. A single snapshot of this pattern replaces multiple cameras: the computer uses it to calculate exactly how the light waves traveled and builds a hologram. The hologram is then displayed on a screen that controls light, and the viewer sees a 3D scene.
The system demonstrated live video at about 28 frames per second. Data transmission required only a standard internet connection. This is a step toward simple, inexpensive devices for 3D video calls — without bulky cameras and mirrors.
The speckle pattern from a laser on a wall is not just pretty: it encodes information about the surface that reflected the light. The new system uses a similar principle, but instead of a wall, it uses a special plate.