Using hierarchy architecture of Morpho butterfly scales for chemical sensing: Experiment and modeling

In this work, the hierarchical micro/nanostructures of Morpho butterfly scales were employed for chemical sensing purposes. We observed that the color and the brightness of the butterfly wings change obviously when the surrounding medium was altered. With an optical system setup, we quantified the shift of the major reflection peak and the change in peak intensity, which corresponds to the observed change of color and brightness. In order to guiding the engineering design of artificial butterfly scales as a new platform for chemical sensors, we further constructed two-dimensional optical models with three different geometrical designs. Rigorous coupled wave analysis technique was employed to analyze the models. By comparing the modeling results with experiments, we identified the key characteristics of the butterfly scales that were relevant to chemical sensing applications. These characteristics should be implemented and optimized in designing and fabricating the bio-inspired sensors for sensitive and selective detection of closely related chemicals.