Séminaire de Michel Mitov: Design, optics, and structure of complex-twist chiral liquid crystals

Design, optics, and structure of complex-twist chiral liquid crystals

Michel Mitov, CEMES, Toulouse

The twisted structure of chiral liquid crystals known as cholesterics is seen everywhere in biology, including the architecture of key macromolecules and biopolymers such as DNA, collagen, chitin, and cellulose. It is crucial in photonic crystals, optical property research, and current non-display applications. The cholesteric structure is distinguished by the selective reflection of light, which is determined by the helix pitch, as well as the polarization selectivity of the reflected light. The present and future of research in the subject are structures with complex twist, that is, non-uniform: gradual, frustrated, curved, with a dual sense, or with an antagonistic molecular anchoring to the limits. In this context, we will discuss issues and recent findings in femtosecond pulse compression and stretching, biological micromirrors with wavelength-selective focusing, optical tags, the challenges of biomimicry of iridescent and patterned insect cuticles, and futuristic projects in the field of autonomous vehicle guidance.

References:

• Dispersion of 20 fs pulses through band edges of cholesteric liquid crystals
  M. Neradovskiy, A. Scarangella, A. Jullien, and M. Mitov, Optics Express 27, 21794 (2019).
   
• Biomimetic Design of Iridescent Insect Cuticles with Tailored, Self-Organized Cholesteric Patterns
  A. Scarangella, V. Soldan and M. Mitov, Nature Comm. 11, 4108 (2020).
   
• Biomimicry of iridescent, patterned insect cuticles: comparison of biological and synthetic, cholesteric microcells using hyperspectral imaging
  A. Jullien, M. Neradovskiy, A. Scarangella, and M. Mitov, J. Roy. Soc. Interface 17, 20200239 (2020).
   
• Hyperspectral topography of the twisted, cholesteric patterns of an insect cuticle under various conditions of helix obliquity
  A. Jullien, M. Neradovskiy and M. Mitov, APL Photon. 5, 096102 (2020).