Laser-guide-star systems for astronomical applications

With computational techniques developed in the investigation of high-energy laser-beam-control systems, a set of concise analytic models describing the essential properties of a laser-guide-star phase-conjugation system has been assembled. With the aid of these models an optimization strategy for mating adaptive optics to a 4-m-class optical telescope is evolved, and it is shown that such a system might be expected to improve the effective atmospheric seeing conditions by nearly a factor of 10 within the isoplanatic patch of the turbulence probe. For operation at visible wavelengths, a compensation system having ~300 actuators and a closed-loop bandwidth of 20 Hz is recommended. All the key hardware components have already been built and tested, with the exception of a suitable laser source for high-repetition-rate illumination of the Earth’s sodium layer.