Optical tricks to image habitable planets around nearby stars

Direct imaging of exoplanets is essential to characterize their surfaces and atmospheres, and identify biological activity. Direct observation of exoplanets is however extremely challenging, due to the large ratio between starlight and planet light, combined with the small angular separation between the two objects. Conventional telescopes cannot perform such observations, and newly developed optical techniques, specifically designed for high contrast imaging, must be employed. High contrast imaging systems include two essential subsystems: (1) a coronagraph must optically block bright starlight while preserving the faint light from the planet(s) nearby and (2) an adaptive optics system must maintain the exquisite wavefront quality necessary for the coronagraph to operate at high contrast.