Risley prisms: 125 years of new applications



Nearly everyone today is familiar with at least one use for optical scanners, the laser bar code scanners found at the checkout counters in virtually every retail store.

What many people may not know is that optical scanners are essential components of many modern scientific instruments. In astronomy, for example, scanning spectrometers have been widely used for many years, and more recently optical scanning technology has been used to build motion compensators for large aperture astronomical telescopes (See for example, http://www.noao.edu/noao/noaonews/dec92/art29.html).