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

TL;DR

This study uses optical diffraction to analyze the long-range order and symmetry of microstructures on insect wings, revealing new insights into their organization and genetic influences for potential biomimetic applications.

Contribution

It introduces a simple optical diffraction method to probe the spatial correlation and symmetry in complex biophotonic structures on insect wings, including genetic reorganization detection.

Findings

Reproducible far-field diffraction patterns observed in transmission.

Long-range semi-periodic order of microstructures over millimeter scale.

Optical detection of genetic reorganization in Drosophila wings.

Abstract

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.