"We have unlocked one of nature's secrets and combined this knowledge with state-of-the-art nanofabrication to mimic the intricate optical designs found in nature,' said Mathias Kolle of Cambridge University.

"Although nature is better at self-assembly than we are, we have the advantage that we can use a wider variety of artificial, custom-made materials to optimise our optical structures."

Kolle collaborated with Professors Ullrich Steiner and Jeremy Baumberg on a study of the Indonesian Peacock or Swallowtail butterfly (Papilio blumei).

The butterfly's wing scales are composed of intricate, microscopic structures that resemble the inside of an egg carton.

Their shape and the fact that they are made up of alternate layers of cuticle and air results in intense colours.

Using several nanofabrication procedures, Kolle and his colleagues made structurally identical copies of the butterfly scales.

These copies produced the same vivid colours as the butterfly's wings.

Being able to mimic these colours has promising applications in security printing.

"These artificial structures could be used to encrypt information in optical signatures on banknotes or other valuable items to protect them against forgery," said Kolle.

"We still need to refine our system but in future we could see structures based on butterflies wings shining from a £10 note or even our passports."

In fact, the butterfly may itself be using its colours as a security measure -- appearing one colour to potential mates but another colour to predators.

"The shiny green patches on this tropical butterfly's wing scales are a stunning example of nature's ingenuity in optical design," Kolle said.

"Seen with the right optical equipment these patches appear bright blue, but with the naked eye they appear green."

"This could explain why the butterfly has evolved this way of producing colour."

"If its eyes see fellow butterflies as bright blue, while predators only see green patches in a green tropical environment, then it can hide from predators at the same time as remaining visible to members of its own species."