High-power guidestar lasers are ready for next-generation AO astronomy

With its virtual elimination of the effects of atmospheric turbulence, adaptive optics (AO) has allotted leading ground-based astronomical telescopes to resolve almost as well as if they were operating in space, Some optical telescopes now being planned will be far too large to loft into space; AO will be essential to the function of these mammoth ground-based instruments. When combined with Toptica's free-space coherent beam combination (CBC) and the latest compact SHG resonator design, an output of more than 20 W at 589 nm was demonstrated (see Fig. 2).1,2 To develop a deployable laser guidestar, we were faced with new chai lenges such as advancing the RFA technology to use polarization-maintaining fibers, developing a high-power polarization-maintaining fiber laser to pump the RFA, implementing an all-in-fiber CBC scheme, and designing a compact and reliable laser system for remote operation at high altitudes.