Source for Sodium Laser Guide Stars

Ground-based optical astronomy has been revolutionized by a technology called adaptive optics, which enables very high-resolution images near the theoretical limit of large telescopes by significantly reducing the distortions produced by atmospheric turbulence. Adaptive optics relies on a high altitude “guide star” as a reference beacon when observing very faint objects. Unique laser technologies were invented to generate a high power, very accurate, single frequency source to excite sodium atoms in the mesosphere, 90 km above the surface of the Earth, producing a beacon for the adaptive optics. This technology involves combining two infrared lasers in a non-linear material to produce yellow light. Two devices were built for the Starfire Optical Range for imaging satellites. All previous attempts to build laser devices for this purpose in the past 20 years have not met the expectations of the astronomy community for required performance and reliability on the telescope. This technology is now highly sought-after by the worldwide astronomy community. The desire for the technology has come about primarily due to the performance of the system as built by the US Air Force Research Laboratory for its 3.5-meter adaptive optical telescope at the Starfire Optical Range at Kirtland AFB, NM.