Metaadaptive optics

The evolution of the adaptive optical systems (AOS) based on the use of spatial light modulators (SLMs) is outlined as well as their possible lines of future development. A conventional scheme of AOS consists of two basic units, the wavefront sensor and the wavefront compensator. Recently there appeared AOS relying on the use of only one SLM, which is then programmed as to combine these both functions. Further development of AOS implemented on SLMs would involve a preceding or real-time adaptation of their characteristics for correct dealing with different kind of wavefronts. One of such solutions is to introduce the varifocal lenslets into the Hartmann-Shack sensor, what allows to measure wavefronts of significantly different curvature. Another option is to apply defocus resistant elements, e.g., axicons. This proposal can be improved by including the cancellation of local astigmatism by applying elliptical axicons or elliptical zone plates of adequate ellipticity. In general the whole aberration can be divided in a constant part for which the system acts in the open loop mode and closed loop mode for the remaining variable part.