Optical Lattices on Wings of Apatura Butterflies

Abstract

Optical microscopy of scales from the wings of the male butterfly Apatura ilia reveals parallel fibers with a spacing of about 710 nm. These fibers, together with tiny transverse grooves, cause violet blue or blue iridescence due to interference of light on the wings, which normally have brown pigmentation.

Here we establish the dependence of the sudden color changes on variable illumination and observation angle.

Keywords

• photonic nanostructures
• iridescence
• optical lattices
• light diffraction
• Bragg's law