Correction of ocular and atmospheric wavefronts: a comparison of the performance of various deformable mirrors

Abstract

The main applications of adaptive optics are the correction of the effects of atmospheric turbulence on ground-based telescopes and the correction of ocular aberrations in retinal imaging and visual simulation. The requirements for the wavefront corrector, usually a deformable mirror, will depend on the statistics of the aberrations to be corrected; here we compare the spatial statistics of wavefront aberrations expected in these two applications. We also use measured influence functions and numerical simulations to compare the performance of eight commercially available deformable mirrors for these tasks. The performance is studied as a function of the size of the optical pupil relative to the actuated area of the mirrors and as a function of the number of modes corrected. In the ocular case it is found that, with the exception of segmented mirrors, the performance is greatly enhanced by having a ring of actuators outside the optical pupil, as this improves the correction of the pupil edge. The effect is much smaller in the case of Kolmogorov wavefronts. It is also found that a high Strehl ratio can be obtained in the ocular case with a relatively low number of actuators if the stroke is sufficient. Increasing the number of actuators has more importance in the Kolmogorov case, even for the relatively weak turbulence considered here.

Characterization and training of a 19-element piezoelectric deformable mirror for lensing

“…The influence functions, from the mathematical point of view, form the natural basis for the manipulation of the wavefront. The corresponding weight of each actuator to the reference mirror surface shape, s can be calculated by [9,10]:…”

“…A second goal was to close the loop and train the PDM to provide focus and defocus for real-time divergence control. In this case, training refers to the process of determining the voltage commands necessary to This type of deformable mirror has been characterized by other groups [8,9] but not for real-time beam control. The requirement for this latter functionality is generated by the need for readily implementable, low cost methods for establishing and sustaining robust free space laser-based communications over long ranges.…”

Wavefront Shaping by a Small-Aperture Deformable Mirror in the Front Stage for High-Power Laser Systems

“…However, the maximum wavefront correction provided by an SLM is limited in 2π, which cannot correct the large wavefront error in complex high-power lasers. Compared with SLMs, commercially available DMs are capable of wavefront correction with an adjustment range of up to several or even tens of micrometers [27,28]. Therefore, DMs are considered to be promising for correcting the low-frequency and large-area spatial wavefront distortion in a complex high-power laser system.…”

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

“…Based on its dynamic deformation, an AO system can compensate for wavefront errors in real time and improve the overall performance in many applications, including vision science and astronomical telescopes. 1 Compared with conventional manually assembled DMs, 2 the micro-electro-mechanical systems (MEMS)-based DM is attracting growing interest because of its low cost, small size, and batch fabrication capability. 3 In general, the MEMS DM can be manufactured by either surface micromachining or bulk micromachining processes.…”