LASER FOR GENERATING A SODIUM-FLUORESCENCE GUIDE STAR

THE IMAGING PERFORMANCE OF GROUND-BASED ASTRONOMICAL TELESCOPES IS COMPROMISED BY ATMOSPHERIC TURBULENCE. THERE IS INCREASED INTEREST IN THE USE OF ADAPTIVE OPTICS TO CORRECT FOR ATMOSPHERIC DISTORTION. ONE GENERAL CONCEPT FOR ATMOSPHERIC COMPENSATION INVOLVES THE USE OF A SO-CALLED ARTIFICIAL GUIDE STAR, CREATED BY ILLUMINATION OF THE MESOSPHERIC SODIUM LAYER, TO GENERATE THE INFORMATION NEEDED FOR CONTROL OF THE ADAPTIVE OPTICS. THE INTENT OF THIS EFFORT IS TO DESIGN AND TEST KEY ELEMENTS OF A PROTOTYPE SOLID STATE LASER FOR USE WITH A SODIUM-GUIDE-STAR SYSTEM. THE LASER EMPLOYS SUM-FREQUENCY GENERATION OF PULSED, 589-NM RADIATION FROM TWO ND:YAG LASERS OPERATING AT 1065 AND 1319 NM.