Spectroscopic characterization of dragonfly wings common in Japan

A series of Fourier Transform infrared (FT-IR) absorption, X-ray diffraction (XRD), and Brillouin light scattering (BLS) studies on the wings of six species of dragonfly common in Japan, including the largest Anotogaster sieboldii and much smaller Lestes temporalis, was performed at room temperature. XRD and FT-IR results indicate that dragonfly wing is comprised of a randomly oriented microcrystalline or an amorphous-like α-chitin. We observed a pair of longitudinal acoustic (LA) phonon peaks and a broad quasi-elastic scattering peak in backscattering BLS spectra. LA phonon frequencies and full widths at half maximum were found to be 19.5 ± 0.4 GHz and 1.0 ± 0.2 GHz for the 488 nm excitation and independent of their sizes and species.