Characterization of planar periodic structure using inverse laser scanning confocal microscopy moiŕ method and its application in the structure of butterfly wing

An effective measuring method for characterizing the planar periodic structure on specimen surface, i.e., inverse laser scanning confocal microscopy moiŕ method, is presented and verified by experiments in this paper. The planar character of the periodic surface structure in a large region of several hundreds of millimeters, as well as the dimension at micro- and nanoscales, can be obtained through seeking the specimen grating equation as well as the virtual strain distribution. Verification experiment is carried out using a 1200 linesmm holography grating as the specimen. The calculated results are in good coincidence with the actual character, demonstrating the validity, feasibility, and high accuracy of this method. Applying this method into identifying the structure of butterfly wing, gratings composed of a cluster of curves with pitches of a little less than 438 nm are found on multiscales of butterfly wing, which provides the possibility for further explaining its attractive iridescence. Furthermore, this method is greatly promising for providing simple, reliable support for bionics, grating fabrication, and maybe the sliding mechanism of crystal lattice.