Experimental evaluation of a positive-voltage-driven unimorph deformable mirror for astronomical applications

摘要

A modified low-cost unimorph deformable mirror (DM) driven only by positive voltages for atmospheric turbulence compensation is presented. The 214 patterned inner actuators generate convex deformations for aberration correction, while one outer ring actuator generates an overall concave bias. To evaluate the aberration correction capability of the proposed DM, the iterative reconstruction of Zernike aberrations and correction were performed in an adaptive optics test system. The experimental results indicate that the fabricated DM has an excellent aberration correction capability, particularly matching the first 20 term Zernike aberrations with the normalized residual root-mean-square (RMS) error <5%. Furthermore, the random atmospheric turbulence aberrations were simulated based on Karhunen-Loève coefficients and reconstructed using the fabricated DM. The simulative and experimental results show that the atmospheric turbulence aberrations can be steadily compensated with 2/40 (λ = 2.2 μm) RMS residual error, indicating the prospect for atmospheric applications.