There are multiple technologies that permeate science fiction, and among them is the hologram. Holograms use interface from reflection off of a source to create what look like 3D images on a flat medium. Many people would like to see this technology used to develop new displays, and researchers at MIT have recently built a chip that should help with that.
The key to holograms is interference, so if you want a hologram to change, you need to be able to change the interference involved in producing it. That is not a very easy task though, due to the wavelengths of visible light, but there have been some clever solutions to this problem. One such solution was to use sound waves to alter the index of fraction of a material, but this required large, expensive crystals that could not support TV resolution. What the MIT researchers have done though is actually turn to a smaller crystal and, most importantly, waveguides. These waveguides are what the red, green, and blue laser light travel though, together, and using acoustics the different frequencies can be filtered, and their interference patterns controlled.
The researchers built the chip with the waveguides in it for just $10, using equipment already at MIT, making it the cheapest component of the prototype display they built. Despite its low cost though, it is capable of producing TV resolution frames and updating them at 30 frames per second; enough for video.