Portable COTS RGB Wavefront Sensor

Abstract

Atmospheric effects reduce the ability to detect or identify objects of interest due to spatial and spectral scintillation. Algorithms alone cannot correct for turbulence over long-range horizontal paths. While adaptive optics (AO) work well for astronomical viewing, the same methods do not adapt directly for complex imagery over long-range horizontal paths. In this two-year research project, we combine an off-the-shelf high-frame-rate USB3 color camera with a compact 90 mm Maksutov-Cassegrain telescope to create a portable red/green/blue (RGB) wavefront sensor. The 90 mm aperture is covered with an aluminum plate holding three separate narrowband color filters. These filters, specifically matched to the relative spectral response of the sensor’s Bayer mask, provide nearly complete separation of the three color planes. This device enables portable imaging through atmospheric turbulence and analysis thereof, where relative motion of the three-color Bayer-pixel video provides real-time wavefront information on the second-order statistics of Kolmogorov turbulence. We not only extract dwell-averaged wavefront tip and tilt as a function of time but also, using our spectral filtering algorithm, are able to fit higher-order modes to the imaged wavefront statistics. In our second year, we will combine this sensor with a deformable mirror to complete the AO system for long-range horizontal paths.