Deformable mirror (DM) used for intracavity compensation in high-power lasers should be able to withstand very high laser intensity. This paper proposes a water-cooled unimorph DM which can withstand the laser power up to 10 kW in thermal simulation. The proposed DM consists of an annular PZT layer and a circular Si layer which are glued together with edge clamped. All the 32 piezoelectric actuators are distributed around the correction area and on the front side of the DM. The cooling water flows through the back side of the DM and cools the mirror directly. This design realizes the physical separation of the actuators and the coolant. The experimental results of a fabricated DM prototype show that the DM can reproduce typical low-order aberrations accurately with relatively large amplitude. The wavefront PV amplitudes of the reproduced tip/tilt, astigmatism, defocus, trefoil and coma shapes for 15 mm aperture are about 40 μm, 24 μm, 18.7 μm, 10 μm and 6 μm, respectively.
Self-accelerating Airy beams have emerged to hold great promise in wide applications due to their non-diffraction and self-healing characteristics. The generation of Airy beams with high quality and high efficiency still remains challenging for conventional diffractive or refractive optical elements. In this Letter, tunable Airy beams with high quality are realized using a reflective adaptive deformable mirror (DM). Both the controllable cubic phase and the compensatory phase for aberrations of the optical system are generated simultaneously to ensure high quality of the resultant Airy beam. Continuous cubic phases with different amplitudes and rotation angles can be readily generated, demonstrating exceptional tunability of the generated Airy beams using a DM device. The intensity profiles and propagation trajectories of the experimentally generated Airy beams are in good agreement with the theoretical results. Benefiting from the intrinsic superiority of a DM with high reflectivity and a high damage threshold, our proposed method for dynamic generation of Airy beams opens up an avenue to plenty of applications such as ultrahigh-power laser shaping, laser fabrication, and optical manipulation.
In order to reduce the cost of the piezo actuator array deformable mirror (DM), a piezoelectric DM driven by unimorph actuator arrays on multi-spatial layers is proposed. The actuator density can be multiplied by increasing the spatial layers of the actuator arrays. A low-cost DM prototype with 19 unimorph actuators located on three spatial layers is developed. The unimorph actuator can generate a wavefront deformation up to 11 µm at an operating voltage of 50 V. The DM can reconstruct typical low-order Zernike polynomial shapes accurately. The mirror can be flattened to 0.058 µm in RMS. Furthermore, a focal spot close to Airy spot is obtained in the far field after the aberrations of the adaptive optics testing system being corrected.