BINARY WAVEFRONT OPTIMIZATION FOR FOCUSING LIGHT THROUGH SCATTERING MEDIA by

SCATTERING MEDIA by XIAOLONG ZHANG (Under the Direction of Peter Kner) ABSTRACT Random light scattering in inhomogeneous media causes strong wavefront aberrations and makes it impossible to focus light. Many wavefront correction techniques have been recently demonstrated to control light propagation in these media. Phase modulation with a spatial light modulator (SLM) and digital light modulator (DMD) have been used to correct the aberrations. And real-time wavefront optimization algorithms have also been developed based on different techniques. In this study, we demonstrate two new techniques, using binary wavefront optimization to focus light through scattering media. We have developed a genetic algorithm and a transmission matrix algorithm for focusing light with binary wavefront optimization. We apply these methods to binary amplitude modulation with both a spatial light modulator and a digital light modulator. With the genetic algorithm, we achieve a focal spot 105 times stronger than the initial average intensity dividing the wavefront into 1024 segments, 64.5% of the theoretical maximum. With the transmission matrix algorithm, we used 6144 segments to achieve a focal spot enhancement of 532, 54.4% of the theoretical maximum.