Manufacturing Photonic Materials: The Biological Option

As yet, technology has not caught up with our desire to create fully three dimensional, micron scale, periodic structures. Drawing patterns on a surface presents few problems to the integrated circuit industry, but that third dimension defeats us for the time being; though not, we suspect, for long.

On the other hand nearly all of biology is `engineered' on the micron scale and with the help of DNA very complex structures are manufactured. Not surprisingly the optical properties are frequently exploited, nowhere with more spectacular effect than in the butterfly. Many species show irridescent green or blue patches and these owe their colouring to diffraction from periodic material in the scales of the wing. On the left is an electron micrograph of a broken scale taken from mitoura grynea revealing a periodic array of holes responsible for the colour.

Below we see a specimen of the Adonis Blue butterfly. Note the blue patches to the rear of the wing.