The <i>Troides magellanus</i> butterfly exhibits a specialized iridescence that is visible only when its hind wings are both illuminated and viewed at near-grazing incidence. The effect is due to the presence of a constrained bigrating structure in its wing scales that has been previously observed in only one other species of butterfly (<i>Ancyluris meliboeus</i>). However, whereas the <i>Ancyluris</i> presents wide-angle flickering iridescence, the <i>Troides</i> butterfly uses pigmentary coloration at all but a narrow tailored range of angles, producing a characteristic effect.
© 2002 Optical Society of America
(050.1950) Diffraction and gratings : Diffraction gratings
(050.1960) Diffraction and gratings : Diffraction theory
(050.1970) Diffraction and gratings : Diffractive optics
(170.1420) Medical optics and biotechnology : Biology
Chris Lawrence, Peter Vukusic, and Roy Sambles, "Grazing-Incidence Iridescence from a Butterfly Wing," Appl. Opt. 41, 437-441 (2002)