Abstract

The MIT holographic video system has displayed color holograms of excellent quality but is limited in its present implementation to images of a few tens of millimeters on a side. This limitation is a consequence of using a polygonal mirror as a horizontal scanning element. It can be demonstrated that the diameter of this scanning polygon scales linearly with the display’s horizontal size, leading rapidly to impractical polygon dimensions. Replacing the polygon by a galvanometric scanner introduces a different set of design constraints since the mirror dimensions scale with the image size. Because the scan rate of a galvanometric scanner goes down as the mirror size is increased, we are faced with unpractically low scan rates for images larger than 5 cm. A solution to this problem is to use an array of small galvanometric scanners. Such low inertia scanners offer an acceptable linear response up to a few hundred hertz but can actuate only small mirrors. The mathematical optics of the MIT display, however, allow for the operation of an arbitrary number of scanning elements working in parallel. This makes possible the display of large images without the use of bulky electro-mechanical components. After a brief description of the issues involved we will describe the latest results obtained by using this novel approach and will show how it could lead in theory to even larger displays.

© 1992 Optical Society of America