  We experimentally probe complex bio-photonic architecture of microstructures
on the transparent insect wings by a simple, non-invasive, real time optical
technique. A stable and reproducible far-field diffraction pattern in
transmission was observed using collimated cw and broadband fs pulses. A
quantitative analysis of the observed diffraction pattern unveiled a new form
of long-range semi-periodic order of the microstructures over mm scale. These
observations agree well with Fourier analysis of SEM images of the wing taken
at various length scales. We propose a simple quantitative model based on
optical diffraction by an array of non-overlapping microstructures with minimal
disorder which supports our experimental observations. Two different
applications of our techniques are demonstrated. First, by scanning the laser
beam across the wing sample we observed a rotation of the original diffraction
profile which gives direct signature of organizational symmetry of
microstructures. Second, we report the first optical detection of
reorganization in the photonic architecture on the Drosophila wings by various
genetic mutations. These results have potentials for design and development of
diffractive optical components for applications and identifying routes to
genetic control of biomemetic devices.
