Simple inexpensive adaptive optical system for large ground-based telescopes at infrared wavelengths

Simple adaptive optical systems are studied that can provide real-time atmospheric turbulence compensation at infrared wavelengths for large ground-based astronomical telescopes. A tip-tilt mirror and a 7-element segmented mirror, along with an iterative adaptive control method, called Far-Field Optimization, provide the turbulence correction. The primary advantage of far-held optimization is that no near-field phase measurements are required, thus eliminating the need for a wavefront sensor that is necessary in conventional adaptive optical systems. Far-field optimization may also somewhat relax the requirements for an artificial guide star. Computer simulations are used to investigate the application of far-field optimization in the presence of drifting atmospheric turbulence and as a function of the spatial granularity and the temporal bandwidth of the adaptive mirror.