Control of photonic bandgaps in chiral liquid crystals for distributed feedback effect

Seiichi Furumi, Shiyoshi Yokoyama, Akira Otomo, Shinro Mashiko

Research output: Contribution to journalConference articlepeer-review

21 Citations (Scopus)


This paper describes two strategies to control the photonic bandgap (PBG) in chiral liquid crystals (CLCs) to generate laser action through the distributed feedback effect. First, we demonstrated the electrical control of supramolecular helical structure and lasing action from the CLCs, which were comprised of an optically active agent and an achiral nematic liquid crystal, doped with a small amount of a fluorescent dye. When the dye-doped CLC cell was optically pumped with linearly polarized laser beam, the laser action took place at the edge(s) of the CLC reflection bands. The threshold pumping energy to induce laser action was dependent on the PBG position of LC hosts. Subsequently, applying voltages to the optically pumped CLC cells over 20 V brought about immediate disappearance of the laser emission due to the supramolecular structural changes of CLCs from planar to focal conic texture. The laser emission could be observed again by reconstruction of the initial planar structure as high voltages over 75 V were switched off. Secondly, the photoinduced tunability of PBG band in CLC and laser oscillation wavelength was explored by using a photoreactive mixture of cholesteryl derivatives. Photoirradiation of the dye-doped CLC cell with 254 nm light brought about continuous changes in the chiral PBG as a result of the predominant photolysis of cholesteryl iodide in the CLC host, leading to the phototunable laser oscillation in a wavelength ranging from 560 to 620 nm. The present report opens promising ways to design novel active mirrorless laser devices by electro- and photo-modulation of the self-organized chiral PBG structures.

Original languageEnglish
Pages (from-to)322-328
Number of pages7
JournalThin Solid Films
Issue number1-2
Publication statusPublished - Mar 21 2006
Externally publishedYes
EventProceedings of the Sixth International Conference on Nano-Molecular Electronics (ICNME 2004) -
Duration: Dec 15 2004Dec 17 2004

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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