PUEO NUI: High contrast imaging and visible AO an upgrade of the CFHT Adaptive Optics Bonnette

The proposal for the upgrade to 104 electrode as submitted to SAC is available here. You can also download the SPIE 2002 paper describing the upgrade, or click here for the PowerPoint presentation.

After the upgrade plan to 36 electrodes was deemed not ambitious enough, some simulations were performed to study the potential and limits of curvature sensing with high numbers of degrees of freedom. The results of this study were presented at the "Beyond conventional adaptive optics" conference, in Venice in 2001. The paper is available here. The advantages are numerous, but most noteworthy are:

• Better image quality at short wavelengths (diffraction limit to H alpha).
• Strehl ratios up to 95% in K band, and improved image stability for cornography, phase coronography and multi-wavelength imaging techniques.
• No degradation of image quality on faint objects, maximum perfomand magnitude estimated at 7.

• Demonstration of Fly-Eyes (replacing the APDs with a CCID-35 detector for the wavefront sensing) with the current 19 electrode system. Even though the new detector will have a 2e- read noise, the overall performance should be improved due to the QE (increased from 40% tp 85%).
• Identifying mirror vendor, lenslet array and real time computer solutions, to build a lab demonstrator/test bench.
• Installing the new components into AOB, and integration off the telescope with an estimated down time of hopefully 6 months to a year.
• Integration on telescope.
• Start thinking about LGS! (See SPIE paper...)