Abstract

The resolution of large ground based astronomical telescopes is limited by atmospheric turbulence to no better than that of a ordinary telescope half a meter in diameter. An atmospheric compensation system consisting of a guide star, wavefront sensor and deformable mirror can correct for atmospheric turbulence and permit a large telescope to achieve resolution close to that of their diffractive limit. Natural guide stars can be used for some applications but the small probability of finding suitably bright guide stars nearby by objects of interest limits their usefulness. To overcome this limitation, artificial guide stars can be generated using lasers tuned to the 589 nm resonance line of mesospheric sodium which exists in a thin layer at the top of the atmosphere at 100 km.

© 1994 Optical Society of America