List of Figures

1. Schematic diagram showing wavefronts passing through the atmosphere
2. Algorithm used to estimate air density as a function of altitude for simulations of atmospheric seeing effects
3. Algorithm used to estimate refractivity as a function of altitude and wavelength for simulations of atmospheric seeing effects
4. Simulated short exposure through a $4r_{0}$ diameter aperture
5. Simulated short exposure incorporating atmospheric dispersion
6. Phase in a short exposure from a large telescope
7. Atmospherically induced optical delay at one timepoint as a function of position in one AT aperture plane at $1.97\mbox{ $\mu$m}$ wavelength.
8. Optical delay at $2.43\mbox{ $\mu$m}$ wavelength at the same timepoint.
9. Optical amplitude and phase in the AT aperture plane at $1.97\mbox{ $\mu$m}$ wavelength.
10. Optical amplitude and phase in the AT aperture plane at $2.43\mbox{ $\mu$m}$ wavelength.
11. Intensity in the image plane at $1.97\mbox{ $\mu$m}$ wavelength
12. Intensity in the image plane at $2.43\mbox{ $\mu$m}$ wavelength
13. The delay in the wavefront in the AT aperture at four timesteps after the tip and tilt Zernike modes have been corrected.
14. The corresponding optical amplitude in the AT aperture plane.
15. Optical amplitude (upper panel) and phase at $1.97\mbox{ $\mu$m}$ wavelength in the aperture plane before the StS.
16. Optical amplitude (upper panel) and phase at $1.97\mbox{ $\mu$m}$ in the aperture plane after an image-plane knife-edge.
17. Optical amplitude and phase with the opposite knife-edge (corresponding to the other beam from the StS).
18. Optical amplitude (upper panel) and phase at $2.43\mbox{ $\mu$m}$ wavelength in the aperture plane before the StS.
19. Optical amplitude (upper panel) and phase at $2.43\mbox{ $\mu$m}$ in the aperture plane after an image-plane knife-edge.
20. Optical amplitude and phase with the opposite knife-edge (corresponding to the other beam from the StS).
21. The measured optical phase compared with the piston mode in simulations
22. The measured optical phase with two group delay measurement algorithms
23. Temporal power spectra of fringe motion
24. The amount of phase jitter introduced by wavefront corrugations
25. S/N ratio for fringe tracking with large apertures