The performance of any adaptive optics system is largely determined by the strength and number of actuators of the corrective element. Deformable phase plate (DPP) technology, recently developed by our group, allows for high order aberration correction in transmission, as it features a large number of transparent electrostatic actuators across the optical aperture. However, DPPs require high operating voltages to provide competitive stroke, which is currently provided by costly analog amplifiers. Pulse width modulation (PWM) offers a viable alternative to obtain analog operation at higher voltages without the need for analog amplifiers. It also potentially expands the library of optical liquids that can be used, as it is compatible with polar liquids acting as the dielectric. In this study we discuss the design, implementation and testing of an 8-channel PWM driver, which has 50 kHz maximum modulation frequency and 600V maximum drive voltage. A DPP variant designed to correct radial symmetric aberration is used to evaluate the performance of the manufactured PWM driver in terms of maximum deflection, stability, precision and crosstalk between actuators. Furthermore, we also demonstrate that PWM driving allows the use of polar liquids for the DPP technology, widening the library of possible optical liquids for this technology.
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