High resolution photovoltaic position sensing with Ti/Si superlattices.

A detector to sense the position of a beam of light with a resolution of less than 100Angstroms has been fabricated with a Ti/Si amorphous superlattice on p-type Si. There are two regions of photovoltaic sensitivity, a low sensitivity region having a response of 1.6 mV/mm and a high sensitivity region having 1.5 mV/micron. This novel detector can sense the light spot position over large lateral dimensions, while the high central sensitivity region, would permit servo-driving to a null position with a high degree of precision. These characteristics also suggest the use of this device in a variety of other photonic transducers.