Integrated multifunctional reprogrammable MEMS deformable mirror and three-dimensional phase retrieval based adaptive optic system implementations

This research presents a fast three-dimensional phase retrieval approach used to perform optical phase modulation through the use of a segmented Micro-Electro-Mechanical Deformable-Mirror (MEMS-DM).; This research demonstrates novel adaptive optic system laser-beam implementations, for beam splitting, beam steering, beam shaping, beam tracking, and aberration correction, using an inherently multifunctional phased array system. Traditional solutions to beam splitting, beam steering, beam shaping (BS3), and beam tracking and aberration correction 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, polarized, and potentially absorptive devices such as LCDs. In addition, beam tracking and aberration correction techniques require closed loop feedback, which is provided by the closed-loop three-dimensional phase retrieval algorithm implemented in this research.; Using the 3D phase retrieval algorithm with a desired far-field amplitude pattern as a constraint, a segmented wavefront control device is shown to simultaneously perform the aforementioned functions through its inherent reconfigurable operation. The MEMS-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 driving voltages. The MEMS-DM provides the added advantage of “discrete imaging” versus “continuously moving” imaging systems presented by current technology. The MEMS-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 BS3 and beam tracking and aberration correction are presented. Simulations have been developed and presented to represent the optical system and the phase maps, created for the operating MEMS-DM, and the output images. Measured experimental data shows good agreement with model simulations. A comparison between an analog MEMS-DM and a digitally controlled MEMS-DM is presented. Overall, experimental results demonstrate the efficacy of the 3D phase retrieval algorithm and one phase control device in solving multifunctional optics problems normally solved through traditional techniques and multiple systems/devices. This research extends traditional techniques and solves the problem of real-time “continuously moving” imaging and also exploits the capability of MEMS-DMs in the field of Adaptive Optics (AO) through the advancement of classical optical phased array techniques.; Digital designs and controllers are produced for remote serial and parallel port PC control of digital MEMS-DDMs (Digital Deflection Micromirrors) using advanced digital VHSIC Hardware Description Language (VHDL). The digital designs are implemented using Configuration Programmable Logic Devices (CPLDs) and Field Programmable Gate Arrays (FPGAs) and are presented as interim research and design accomplished to support future work towards integrated All-Digital Multi-Chip Modules (MCM) and Application Specific Integrated Circuit (ASIC) AO system designs.