Abstract: This paper presents a fast 2D phase retrieval approach used to perform optical phase modulation of a Microelectromechanical Deformable-Mirror (MEM-DM). Traditional solutions to beam splitting, beam steering, and beam shaping (BS$+3$/) involve multiple and sometimes costly optical components. For example, beam splitting is normally accomplished with beam splitters, beam steering is normally achieved with gimbaled mechanical devices, and beam shaping is normally done with addressable absorptive devices such as LCDs. Using the phase retrieval algorithm with a desired far-field amplitude pattern as a constraint, a segmented wavefront control device is shown to simultaneously perform the functions of BS$+3$/. The MEM-DM used is a foundry micro-fabricated device that is attractive for optical phase modulation applications primarily because of its inherent low cost and low drive voltages. The MEM-DM shapes the beam based on the results of a modified Fienup and Roggemann/Lee phase retrieval algorithm implemented within the system. The optical bench setup and the experimental results for BS$+3$/ are presented. Measured experimental data shows good agreement with model simulations. A comparison between analog MEM-DMs and a digitally controlled MEM-DMs will be addressed in this presentation. Overall, experimental results demonstrate the efficacy of the phase retrieval algorithm and one phase control device in solving optics problems normally solved through traditional techniques and multiple devices.!20
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