Adaptive Dynamic Range Wavefront Sensor

For a number of years the Air Force Research Laboratory (AFRL) has investigated the fabrication of large optics to support space based sensing and weapons applications. One promising technology is the construction of large membrane mirrors. This class of mirror has significant advantages including the potential of very area-to-weight ratios, low f-numbers, and the ability to launch within tight packaging constraints and then deploy and align in space. The metrology requirements for membrane mirrors are unique. The initial mirror figure and radius of curvature have large departures from the final required shape and for multi-meter size the errors may consist of thousands of waves of higher order spherical aberration. These large errors must be measured so that an actuation system can be used to reduce the error to within at least tens of waves of the desired surface. This proposal presents a novel approach to provide an adaptive technique to adjest the dynamic range of the wavefront sensor while maintaining the spatial resolution and accuracy required.