Enhancement of the optical absorption in cholesteric liquid crystals due to photonic effects: an experimental study
| Autor: | Jesús Etxebarria, Josu Ortega, César L. Folcia |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Cholesteric liquid crystal business.industry Physics::Optics 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Molecular physics Photonic metamaterial Wavelength Liquid crystal 0103 physical sciences Optoelectronics General Materials Science Photonics 010306 general physics 0210 nano-technology business Absorption (electromagnetic radiation) Luminescence Photonic crystal |
| Zdroj: | Liquid Crystals. 45:122-128 |
| ISSN: | 1366-5855 0267-8292 |
| DOI: | 10.1080/02678292.2017.1302010 |
| Popis: | An anomalous strong optical absorption was measured in a cholesteric liquid crystal (CLC) at both edges of its photonic band gap. The experiment was carried out by studying the luminescence generated by the CLC sample doped with a small amount of fluorescent dye. The material was excited with monochromatic light at different angles of incidence and polarisations. Clear peaks were found in the luminescence response at angles for which the pumping wavelength coincides with the positions of the gap edges. The effect is especially noticeable for excitation under circularly polarised light of the same handedness as that of the CLC helix, and it is the highest at the long-wavelength edge. The modification of the absorption is originated by the helicoidal (photonic) structure of the material, which drastically influences the propagation of electromagnetic waves at certain frequencies and polarisations. The results were analysed numerically using an extension of the Berreman method that incorporates absor... |
| Databáze: | OpenAIRE |
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