Fatigue characteristics of deformable mirrors caused by fatigue of lead zirconate titanate.

The correction ability of deformable mirrors (DMs) with different fatigued degrees has been studied by quantitatively analyzing the fitting wavefront, the times-diffraction-limit factor β, and the wavefront power spectral density (PSD). The results indicate that the fatigue of DMs can be ignored when the DM continually works below 105 cycles, while the performance of the DM degrades gradually if the loading cycles of the DMs exceed 105 . Consequently, the peak-valley (PV) value of the fitting wavefront of the DM decreases with the increase of the fatigue degree of the DM, resulting in the increase of the PV value of the corresponding residual wavefront. Meanwhile, the larger PV value of the distorted wavefront or the higher proportion of the high-spatial-frequency components gives rise to the larger residual wavefront after the existence of the fatigue of the PZT actuators, the worse corrected beam quality, and the lower correction ability of the DM. The correction ability of the DM composed of different piezoelectric ceramics has also been evaluated by the β factor of the corrected laser beam, which indicates that for the given loading cycle, the fatigue degree and the correcting ability of the DM composed of different piezoelectric ceramics are different.