American scientists have learned to create three-dimensional colored holograms, similar to sculpture. To do this, they quickly moved the opaque particle with the optical trap and covered it with lasers of different colors. Created image reach the size of several centimeters and can be replaced with a frequency of up to thirteen frames per second. Article published in Nature.
For the first time, holograms — three-dimensional images of objects — learned how to get in 1947, Hungarian physicist Denes Gabor. In the proposed scheme has been used coherent light beams, which allowed to record not only the amplitude but also the phase of the waves. In the future the schema of a Gabor improved, but the principle of creating holograms in General remained the same. Such holograms are now widely used — for example, you can find them on excise stamps. However, they have a serious drawback: the holographic image can be observed only in a limited range of angles, it cannot rotate and examine from all sides. These holograms are nothing like those three-dimensional images from science fiction.
On the other hand, in recent years scientists have proposed several methods of manufacturing three-dimensional display (volumetric display) devices, which allow to obtain truly three-dimensional holograms, similar to sculpture. In such devices, the light scatters not on wax, but directly on the dots forming the image (roughly speaking, floating in the air dust). At the moment, scientists have developed several types of such displays, including induced plasma displays (plasma displays induced), modified air displays (modified air displays) and displays that use acoustic levitation (acoustic levitation displays). Unfortunately, these technologies are also far from perfect — plasma displays are not able to create color images, and the last two types may not provide the accuracy comparable to conventional holography.