Technologies > Thin Film Control > Zernike

The ability to actuate a given Zernike mode is important as it is also a strong indicator of the ability to control disturbances with that type of content. Example experimental control results for a range of command Zernike disturbances are shown in below for the first four non-rigid body symmetric Zernikes terms (tip/tilt, astigmatism, trefoil, tetrafoil). All shown results are the outcome of 1 to 2 iterations and are for control over the 80 percent fitting radius. Input boundary strokes were, at a maximum, 2mm. As the experimental results show, a large degree of control authority is provided by boundary control, especially when one takes into account the fact that the shown results are surface measurements. Wavefront measurements would have 2x the surface change. For 500nm wavelength operation, the shown results would thus translate into wavefront authority of 16000 waves (peak-valley).

Experimentally measured boundary actuation authority over common symmetric Zernike terms (Tip/Tilt to Tetrafoil) (Surface contours at 400 um over a 0.5m shell, 2mm input strokes).