Polarization-independent adaptive lens with two different blue-phase liquid-crystal layers

Fast refocusing lens based on ferroelectric liquid crystals

Optical devices like virtual reality (VR) headsets present challenges in terms of vergence-accommodation conflict that leads to visual fatigue for the user over time. Lenses available to meet these challenges include liquid crystal (LC) lenses, which possess a response time in the millisecond range. This response time is slow, while accessing multiple focal lengths. A ferroelectric liquid crystal (FLC) has a response time in the microsecond range. In this article, we disclose a switchable lens device having a combination of the fast FLC-based polarization rotation unit and a passive polarization-dependent LC lens. A cascaded combination of three such lens units allows access to eight different focal points quite rapidly and can be a convenient device for VR applications.

Templated blue phases

Cholesteric blue phases of a chiral liquid crystal are interesting examples of self-organised three-dimensional nanostructures formed by soft matter. Recently it was demonstrated that a polymer matrix introduced by photopolymerization inside a bulk blue phase not only stabilises the host blue phase significantly, but also serves as a template for blue phase ordering. We show with numerical modelling that the transfer of the orientational order of the blue phase to the surfaces of the polymer matrix, together with the resulting surface anchoring, can account for the templating behaviour of the polymer matrix inducing the blue phase ordering of an achiral nematic liquid crystal. Furthermore, tailoring the anchoring conditions of the polymer matrix surfaces can bring about orientational ordering different from those of bulk blue phases, including an intertwined complex of the polymer matrix and topological line defects of orientational order. Optical Kerr response of templated blue phases is explored, finding large Kerr constants in the range of K = 2-10 × 10(-9) m V(-2) and notable dependence on the surface anchoring strength. More generally, the presented numerical approach is aimed to clarify the role and actions of templating polymer matrices in complex chiral nematic fluids, and further to help design novel template-based materials from chiral liquid crystals.