Adaptive Optics

NFIRAOS Wide Field Mode will deliver images to IRMS that will produce almost an order of magnitude gain in encircled energy within 160″ slits over the entire of 2′ diameter field. These IRMS performance estimates were generated by the TMT AO analyst Luc Gilles in 2010. The solid curves are performance predictions for atmospheric turbulence and WFS noise effects only. Please note that enclosed energies are plotted as a function of the full (not half) slit width. The dashed and dotted curves include the additional wavefront errors due to implementation effects based on two models. ♦ Dotted: Errors have a white spatial frequency spectrum, and the impact on the enclosed energies is estimated using Marechel's approximation. ♦ Dashed: Errors have a Kolmogorov spectrum, and the impact on the enclosed energies is estimated by multiplying the OTF by a transfer function in the spatial frequency domain. You'll notice that the dashed curves aren't that much different from the solid curves for a 160 mas slit width, although more work is needed to estimate the actual structure function for these implementation errors. Reference: TMT Instrumentation and Performance Handbook (TMT, 2010) The TMT Instrumentation Program (L.Simard+, SPIE, 2010) The potential of J-band stellar spectroscopy with ELTs (C.Evans+, A&A, 2011)