Optimization of Sodium Guide Star Return using Polarization and Modulation Control

Through simultaneous control of the polarization and frequency modulation of an outgoing continuous-wave (CW) sodium guide star laser beam, demonstrate a new concept to maximize the resonant backscattered flux per watt of projected laser power, taking advantage of enhancements from both optical pumping of mesospheric sodium atoms to a trapped transition and alignment of the atoms with the geomagnetic field in the Larmor precession cycle. Demonstrate the beam control concept with a single-frequency sodium laser in the laboratory. Through detailed physics-based modeling, establish the radiometric performance of a laser guide star (LGS) using the new method. Define the cost and scope of the Phase II program to construct a prototype beam control system to be demonstrated in the field.