A liquid crystal device for speckle reduction in coherent light

High coherence in laser light causes spatially distributed interference called speckle. In applications such as holographic projection, this undesirable side effect degrades image clarity. The current methods of speckle reduction, such as a rotating ground-glass diffuser, require additional bulky moving parts. In this thesis an alternative technology is presented based upon a compact chiral nematic liquid crystal device. A spatially-random, time-varying phase modulation of the incident light is achieved through the electrohydrodynamic instabilities that are induced by an alternating electric field. In this thesis, through material and device optimisation, a LC diffuser is fabricated that is capable of reducing speckle contrast to C=0.07 with transmission of just over 50%.