Holodust is essentially a swept-volume volumetric display, where the volume is a stochastic distribution of dust-like particles.
The device works by rapidly sweeping an infrared laser throughout the display space. When the laser encounters a particle, some light is scattered and is picked up by high-speed position-sensing photodetectors. If that particle's position is deemed to be lit according to the model in voxel memory, a second laser, a visible one coaxial to the invisible one, is flashed on.
When repeated rapidly with an appropriate distribution of particles, a coherent 3D image is formed.
