Concept design and performance estimation of a sodium laser guide star adaptive optics system for field demonstration

摘要

To facilitate our adaptive optical telescopes' high-resolution detection ability for dim celestial objects in the future, a laser guide star (LGS) adaptive optics (AO) imaging system for field experiment and demonstration is designed and analyzed. A macro-micro mode-locked pulsed laser of about 25 watts will be employed to excite the sodium atoms in the mesosphere. In order not to modify the structure of the 2-meter telescope, an independent off-axis launch telescope will be used to project the laser into the sky. A small-scale AO imaging system test bench under LGS operation mode is designed to integrate with the telescope in the Coude room. Based on the system conditions and the observatory's presumptive turbulence parameters, the system performance is preliminarily estimated. The result shows that a ~1 arcsecond laser spot as well as a 4.1-times diffracted limited resolution will be obtained by this experimental system.