ABSTRACT
We present a closed-loop adaptive optics system based on a holographic sensing method. The system uses a multiplexed holographic recording of the response functions of each actuator in a deformable mirror. By comparing the output intensity measured in a pair of photodiodes, the absolute phase can be measured over each actuator location. From this a feedback correction signal is applied to the input beam without need for a computer. The sensing and correction is applied to each actuator in parallel, so the bandwidth is independent of the number of actuator. We demonstrate a breadboard system using a 32-actuator MEMS deformable mirror capable of operating at over 10 kHz without a computer in the loop.
ABSTRACT
We demonstrate, for the first time to our knowledge, the use of a photorefractive polymeric composite to clean a phase-distorted laser beam and reconstruct a badly distorted image. Advantageous qualities including relatively high figures of merit, ease of processability, and low cost make this class of materials attractive when compared with their inorganic crystalline counterparts. In addition, we used four-wave-mixing and holographic techniques to obtain an internal diffraction efficiency of approximately 31% at 54.5 V/micron and a two-beam-coupling gain coefficient of gamma = 17 cm-1 at 54.5 V/micron under our experimental conditions.
ABSTRACT
We demonstrate, for the first time, the dynamic correction of aberrated images in real-time using a polymeric composite with fast response times. The current novel experimental design is capable of restoring a phase aberrated, image carrying laser beam, to nearly its original quality. The ability to reconstruct images in real-time is demonstrated through the changing of the aberrating medium at various speeds. In addition, this technique allows for the correction of images in motion, demonstrated through the oscillatory movement of the resolution target. We also have demonstrated that important parameters of the materials in the study such as response times, diffraction efficiencies and optical gains all retain high figures of merit values under the current experimental conditions.
