Characterization of a bimorph deformable mirror using stroboscopic phase-shifting interferometry

Abstract

The static and dynamic characteristics of a bimorph deformable mirror (DM) for use in an adaptive optics system are described. The DM is a 35-actuator device composed of two disks of lead magnesium niobate (PMN), an electrostrictive ceramic that produces a mechanical strain in response to an imposed electric field. A custom stroboscopic phase-shifting interferometer was developed to measure the deformation of the mirror in response to applied voltage. The ability of the mirror to replicate optical aberrations described by the Zernike polynomials was tested as a measure of the mirror's static performance. The natural frequencies of the DM were measured up to 20 kHz using both stroboscopic interferometry as well as a commercial laser Doppler vibrometer (LDV). Interferometric measurements of the DM surface profile were analyzed by fitting the surface with mode-shapes predicted using classical plate theory for an elastically supported disk. The measured natural frequencies were found to be in good agreement with the predictions of the theoretical model.

Numerical simulation of a bilayer PMN ceramic bimorph deformable mirror

“…Similarly, the maximum concave deformation, as shown 26.45 m in Fig.5(b), is produced when the front face electrode and middle common electrode are grounded while all back face electrodes are driven to 300 V. Simulation results show that the stroke of the bilayer PMN DM prototype is over 24 m. The stroke of our bilayer PMN bimorph DM is larger than that of most commercial DMs. As the diameter of our bimorph DM is larger than that of AOptix's bimorph DM, the stroke is a little larger even when the biased voltage is smaller [8] .…”

“…Most bimorph DMs are made by PZT, as PZT is relatively mature and has been applied in actuator design. AOptix firstly made a bilayer PMN bimorph DM [8] which has larger curvature deformation, greater linearity and lower hysteresis at room temperature compared with PZT bimorph DMs. In this paper, a bilayer PMN bimorph DM prototype is presented, which is designed with the optimal electrode pattern [9] and has a larger stroke than AOptix's product even with a lower actuated voltage.…”

Performance of a MEMS-based AO-OCT system

“…Spherical mirrors (indicated by S1-S10 in the diagram) re-image the pupil. The system uses an bimorph deformable mirror (DM) made by AOptix Technologies, Inc. for low-order, high-stroke correction 7 and a 140-actuator mirco-electrical-mechanical-system (MEMS) DM made by Boston Micromachines Corporation for high-order correction. 8 These are indicated by DM1 and DM2 in the layout.…”

Performance of 97-elements ALPAO membrane magnetic deformable mirror in Adaptive Optics - Optical Coherence Tomography system for in vivo imaging of human retina

“…The latter modality allows realtime observation of microscopic retinal structures in human eyes, including the photoreceptor cone mosaic, nerve fiber layer and microscopic blood flow in capillaries. Due to the limited axial resolution of these systems, however, they cannot be used to image other retinal layers or to create detailed 3D reconstructions of retinal volumes, a key advantage associated with OCT imaging [6]- [8].As previously reported, the initial configuration of the UC Davis AO sub-system used a 35-actuator AOptix bimorph deformable mirror (DM) for low-order, high-* E-mail: rjzawadzki@ucdavis.edu stroke correction [9] and a 140-actuator Boston Micromachines MEMS DM for high-order correction. The performance of the AO-subsystem of this instrument was previously evaluated and the results were presented by Evans et al [10].…”

“…As previously reported, the initial configuration of the UC Davis AO sub-system used a 35-actuator AOptix bimorph deformable mirror (DM) for low-order, high-* E-mail: rjzawadzki@ucdavis.edu stroke correction [9] and a 140-actuator Boston Micromachines MEMS DM for high-order correction. The performance of the AO-subsystem of this instrument was previously evaluated and the results were presented by Evans et al [10].…”