Birefringence of nanocrystalline chitin films studied by Mueller-matrix spectroscopic ellipsometry
2016 (English)In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 2, 671-681 p.Article in journal (Refereed) PublishedText
Birefringent chitin films were prepared by a dipping technique from aqueous suspensions of chitin nanocrystals in a nematic liquid crystal phase. In the films, chitin nanocrystals are preferentially oriented along the withdrawal direction. Normal incidence transmission Mueller-matrix (M) spectroscopic ellipsometry measurements as a function of sample rotation were used to investigate the optical birefringence in the spectral range 0.73 to 5 eV. Analysis of eigenvalues and depolarization data reveal that the Mueller matrix corresponds to a pure retarder for photon energies below 4 eV and is depolarizing in the range 4 to 5 eV. By modeling the chitin film as a slab with in-plane anisotropy the birefringence was determined. The determination of birefringence was extended to include the range of 4 to 5 eV by a differential decomposition of M. (C) 2016 Optical Society of America
Place, publisher, year, edition, pages
OPTICAL SOC AMER , 2016. Vol. 6, no 2, 671-681 p.
IdentifiersURN: urn:nbn:se:liu:diva-127060DOI: 10.1364/OME.6.000671ISI: 000372039500041OAI: oai:DiVA.org:liu-127060DiVA: diva2:919379
Funding Agencies|Concayt-Mexico; Knut and Alice Wallenberg foundation; Swedish Research Council; Carl Tryggers foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]2016-04-132016-04-132016-05-17