Bioinspired optoelectronic nose with nanostructured wavelength-scalable hollow-core infrared fibers.

IO N The mammalian olfactory system uses about four hundred cross-responsive receptors located at the end of olfactory neurons for exquisite detection and discrimination of tens of thousands of different odorant molecules. Each odorant, with its particular shape, size, functional group, and charge combination, induces a unique combinatorial response, or odorant code, from a library of olfactory receptors; here slight differences between molecules or even a change in the concentration can change the “code” and, therefore, its sensation. [ 1 , 2 ] Built on this biomimetic principle, an artifi cial nose [ 3 , 4 ] is an array-based combinatorial chemical sensor to identify various odorants using different transducing mechanisms, for example, metal oxide semiconductors and FETs; [ 5 – 7 ] chemiresistors; [ 8 , 9 ] poly mercoated microand nano-cantilever arrays; [ 10 , 11 ] and, more recently, fl uorescent-dye-coated fi ber-optic microarrays; [ 12 – 14 ]