Elucidating the fine details of cholesteric liquid crystal shell reflection patterns

Abstract

Clusters of planar-aligned short-pitch cholesteric liquid crystal spheres generate dynamic colourful patterns due to multiple selective reflections from the radially oriented cholesteric helices in neighbour shells at varying distances. These photonic communication patterns were widely investigated for the cases of both droplets and shells, demonstrating not only intriguing optical phenomena but also potential for applications as new optical elements for photonics, sensing or security pattern generation. However, the optics of these clusters is truly complex and until now only the strongest and most fundamental reflections have been analysed and explained. In this report, we elucidate the origin of a number of more subtle reflections and we explain the extension in space of various spots as well as their internal colour variations. ARTICLE HISTORY

Dynamic tuning of the director field in liquid crystal shells using block copolymers

“…Double emulsions of water in liquid crystal (LC) in water, also known as LC shells, have over the last decade acquired a status as a prolific experimental platform for studying confinement effects in soft matter physics [1][2][3], in particular concerning topological defects and their interactions on curved spaces. While the initial work, experimental and theoretical, was restricted to nematic shells (orientational order only; molecules aligning along the director n) [4][5][6][7][8][9][10][11], later efforts have focused also on smectic shells of SmA- [12][13][14][15][16][17][18][19] and SmC-type [17] as well as cholesteric [20][21][22][23][24][25][26] shells. Thanks to advances in providing long-term stability through polymerization/polymer stabilization of LC shells [26][27][28][29], they are also emerging as a realistic basis for innovative applications, for instance in photonics and photonics-derived use cases [20,26,27,[30][31][32][33][34][35], sensing [28,36,37] or uncon...…”

Stimuli‐Driven Control of the Helical Axis of Self‐Organized Soft Helical Superstructures

“…Amplification of photon upconversion has been achieved in CLC microshells where the core was a fluid upconversion system . The fabrication, characterization, and investigation of different aspects of CLC microdroplets and microshells with defined helical axis orientation are being pursued actively …”

The 2017 Luckhurst-Samulski Prize

“…This is indicative of the high viscosity of the phase and accounts for the lack of response to external electric fields. Clearly this paper merits careful attention The final paper of this shortlist is by Jan Lagerwall and his colleagues; its title is Elucidating the fine details of cholesteric liquid crystal reflection patterns [16]. It describes an ingenious study, both experimental and theoretical, describing the creation of shells in which a cholesteric phase is surrounded by two inaccessible isotropic phases.…”