Speckle noise reduction by focal plane wave-front sensing in high contrast imaging optics

For the direct detection of extrasolar planets, a high contrast imaging optics system is required. One of the problems in it is speckle noise due to the wave-front error in the coronagraph optics. We proposed the focal plane wave-front sensing method to reduce the speckle noise and successfully reduced the speckle noise level by 2 order of magnitude.