The TMT Laser Guide Star Facility

The Laser Guide Star Facility (LGSF) system of the Thirty Meter Telescope (TMT) will generate the artificial laser guide stars required by the TMT Laser Guide Star AO systems. The LGSF will use multiple sodium lasers to generate and project several asterisms from a laser launch telescope located behind the TMT secondary mirror. In particular, the LGSF will generate a 6-guide-star asterism for the TMT Narrow Field Infrared Adaptive Optics System (NFIRAOS). In this paper, we will present the LGSF requirements, system level tradeoffs, expected performance and the current status of the design, which is based upon solid state continuous wave, 589 nm lasers and conventional beam transport optics