Optical probing of long-range spatial correlation and symmetry in complex biophotonic architectures on transparent insect wings

摘要

We experimentally probe complex bio-photonic architecture of microstructureson the transparent insect wings by a simple, non-invasive, real time opticaltechnique. A stable and reproducible far-field diffraction pattern intransmission was observed using collimated cw and broadband fs pulses. Aquantitative analysis of the observed diffraction pattern unveiled a new formof long-range semi-periodic order of the microstructures over mm scale. Theseobservations agree well with Fourier analysis of SEM images of the wing takenat various length scales. We propose a simple quantitative model based onoptical diffraction by an array of non-overlapping microstructures with minimaldisorder which supports our experimental observations. Two differentapplications of our techniques are demonstrated. First, by scanning the laserbeam across the wing sample we observed a rotation of the original diffractionprofile which gives direct signature of organizational symmetry ofmicrostructures. Second, we report the first optical detection ofreorganization in the photonic architecture on the Drosophila wings by variousgenetic mutations. These results have potentials for design and development ofdiffractive optical components for applications and identifying routes togenetic control of biomemetic devices.