The effect of the structure on the optical properties of epicular blue spruce wax (Picea pungens)

The study of morphological and optical characteristics of the epicular wax layer of blue spruce (Picea pungens). The method of scanning electron microscopy revealed structural units - tubes with a diameter of 150-200 nm and a length of 3-5 microns. An iridescence effect from the wax layer domains has been detected. In the reflected light, the domains have a blue color, when observed in transmitted light acquire a pinkish tint. These optical characteristics are the main features of the photonic crystal structure. A numerical simulation of the transmission spectrum with the identified structural optical parameters was carried out using the transfer matrix method. The spectrum of the maximum fluorescence coincides with the defect mode of the calculated transmission spectrum.