Thesis Title: The Use of Laser Guide Stars in Astronomy
Chris Neyman's Ph.D. research included both experimental and theoretical investigations of laser guide stars.
On the experimental side, Chris Neyman used a 50 Watt Excimer laser at the 1-m telescope at Mt. Laguna Observatory to project and to detect two Rayleigh laser guide stars that were created and placed side-by-side on the sky. This is a rather difficult experiment to do as Ph.D. thesis student. He did the optical design lay-out, assembled the optics, and spent many nights at the Mt. Laguna 1-m telescope. His aim was to measure the differential motion of the two artificial stars as a feasibility test for the creation of multiple laser guide star systems. On the theoretical side, Chris Neyman built a computer model to simulate the propagation of electromagnetic waves through a turbulent atmosphere -- complete with randomized phase screens -- primarily to simulate the outcome of his experimental work. However, once the computer model was operating, he also ran simulations of the UnISIS laser guided adaptive optics system at Mt. Wilson to determine the extent of focal anisoplanatism (the cone effect) given the finite altitude (18 km) of the UnISIS laser guide star. In a very imaginative aside, Mr. Neyman also derived and published as a separate paper a fundamental limitation as to the accuracy of using artificial laser signals to determine the absolute position of astronomical sources when viewed through the turbulent atmosphere of the Earth.
Even before completing his Ph.D., Dr. Neyman was hired by the Air Force Maui Observing Station (AMOS) where he was eventually appointed as Group Leader of the 3.5-m AEOS Telescope's adaptive optics system. Subsequently, he moved to Keck Observatory where he now works in the interferometry and adaptive optics group.