Simple multi-wavelength imaging of birefringence:case study of silk. Issue 1 (December 2018)

• Record Type: Journal Article
• Authors: Honda, Reo; Ryu, Meguya; Li, Jing-Liang; Mizeikis, Vygantas; Juodkazis, Saulius; Morikawa, Junko
• Is Part Of: Scientific reports. Volume 8:Issue 1(2018)
• Page Start: 1
• Page End: 9
• Publication Date: 2018-12
• Subjects: Natural history -- Research -- Periodicals; Biology -- Research -- Periodicals; Physical sciences -- Research -- Periodicals; Earth sciences -- Research -- Periodicals; Environmental sciences -- Research -- Periodicals; 502.85
• DOI: 10.1038/s41598-018-36114-8
• Languages: English
• ISSNs: 2045-2322

Abstract

Abstract Polarised light imaging microscopy, with the addition of a liquid crystal (LC) phase retarder, was used to determine the birefringence of silk fibres with high (∼1 μ m) spatial resolution. The measurement was carried out with the silk fibres (the optical slow axis) and the slow axis of the LC-retarder set at parallel angles. The direct fit of the transmission data allowed for high fidelity determination of the birefringenceΔn ≈ 1.63 × 10−2 (with ∼2% uncertainty) of the brown silk fibre, (Antheraea pernyi ) averaged over the wavelength rangeλ = (425–625) nm. By measuring retardance at four separate wavelengths, it was possible to determine the true value of the birefringence of a thicker sample when an optical path may include a large number of wavelengths. The numerical procedures and required hardware are described for the do-it-yourself assembly of the imaging polariscope at a fractional budget compared to commercial units.