Duration: 6 months
Laser guide star adaptive optics (LGS AO) is the most promising approach for countering atmospheric distortions in uplink FSOC and laser-based space debris tracing and manoeuvring applications. The best AO performance can be expected when an LGS is created in the sodium layer at 90 km altitude. A major shortcoming of the technique is the sodium LGS's tip/tilt indeterminacy, which means that uplink beam wander cannot be fully controlled, particularly at large point-ahead angles. We propose a cost-effective measurement campaign to explore the feasibility of a polychromatic LGS (pLGS), which would allow us to measure tip/tilt based on the differential tilt between two wavelengths emitted by the pLGS. This research would be part of a community-wide effort to address the tip/tilt indeterminacy of sodium LGS, with complementary work currently underway at ESO and Durham University that explores approaches to tip/tilt estimation from a monochromatic LGS.
