Interferometric wavefront sensors for extreme adaptive optics on the Thirty Meter Telescope

Direct observation of extrasolar Jovian planets will enable detailed investigation and understanding of the formation of these planet populations and also of their relative abundance. Future large telescopes, such as the Thirty Meter Telescope(TMT), will enable the study of such planet populations at relatively small working distances from the parent star. W e present an analysis of an extreme adaptive optics system utilizing a self-referencing phase-shifting interferometer as the primary wave-front sensor. A module of the adaptive optics system consists of a conventional Shack-Hartmann wave-front sensor to provide the initial start-up of the adaptive optics system, thereby placing a significant amount of energy into the core of the point spread function which will act as the reference for the primary interferometric wave-front sensor. The interferometric-based wave-front sensor is shown to provide a significant improvement in the achievable contrast ratio compared with conventional adaptive optics systems containing Shack-Hartmann wave-front sensors.