Living color palettes made up of crystals: Photonic structures

What would you do if you were asked to paint a picture that would never fade without using any painting materials? When you need to form an amazing color scheme, it is clear that it would be impossible to do this without chemical paints. However, in nature, there are beings that can display astonishing colors without using any color pigments since the first day they were created.

Did you know that these beings, which we know very well, are furnished with amazingly beautiful evidences of creation?

When we try to imagine a world without color, we understand more clearly how important colors are for us. There is no doubt that the world we live in, and the universe itself has been furnished with vibrant colors and this is a great blessing created by Allah for us. Every detail, from the green of trees, the blue of the sky, colorful flowers, to the beautiful colors of animals, forms an incomparable harmony in nature. Moreover, in nature there exist  such hues and shades  that it is not possible to compare these to any other color. These colors that never fade are like a display of light for those who look at their strikingly shiny tones and shimmering reflections. Now let us examine how these striking colors form in some creatures.

How Are Colors Formed?

We rarely stop to think of the profusion of colors that surround us, and make the world so beautiful for us to live in; very likely, we give even less thought to how these colors are formed. In order for colors to be formed, first,  light is required. When sunlight falls on an object, the object only reflects the light at a certain wavelength. This light comes to our eyes and turns into electrical signals, and as a result of a series of complex processes it is transmitted to the brain via sight nerves. We perceive colors once these signals are interpreted in the brain.

How Do We See Objects’ Colors?

Chemical substances called “pigments” (used in painting materials) determine colors. Pigments emit certain wavelengths of light and reflect the rest, and we sense the emitted light in that wavelength as color; for example a red flower emits all colors and we perceive it as red thanks to its pigments that only reflect red color. However, research carried out recently has shown that colors can also form in some beings without the use of pigments. So how do these beings display amazing colors without the use of pigments?

Light itself is composed of particles called photons. Photonic structures are created with an order that responds to the movements of photons and ensure that these are directed with specific purposes.

Photonic Structures Instead of Colors in Some Living Beings

At the Museum of Australia where various butterflies are displayed, it was found that some butterflies become discolored, with the pigments losing their effect, while some species maintain their vibrant color even after a long time. As a result, scientists have understood that the source of some colors cannot be pigments alone and they have uncovered that the reason that the colors of these butterflies remains vivid is the “photonic structures” they possess.

One of these butterflies is the species called Morpho rhetenor.
 

•    Striking blue colors that can be distinguished even from very long distances have directed scientists to make research about these living beings.

•    When scientists examined this butterfly in detail, they came across micro crystals, which are a wonder of creation.

•    The multi-layered plates and spaces in the wings of these butterflies have formed a photonic crystal structure by being arranged in a very delicate order. This photonic crystal structure passed through all the other wavelengths of the light and causes the wings of butterflies to appear as blue by reflecting the blue color.
 

Examples of Photonic Structures in Nature

In nature, living beings that form colors as a result of the photonic structures in their bodies, instead of color pigments, use the structural changes that occur as a result of complex reflections of light, refraction and spreading, and thus reflect their colors. The source of the amazing shimmering colors in the wings of butterflies, hummingbirds, parrots and some sea creatures like sea stars are these photonic structures.

Some birds have highly detailed colored feathers. For example, the peacock is a flawless proof of creation with its perfect shimmering colors. When the eyes in the tails of the peacock change position, it seems as though the color has changed. The basic reason for  these shimmering colors is the photonic crystals in these birds’ feathers that has existed since the first day they were created.

A Visual Feast in Nature: Shimmering Colors

Versicolor means an object changing its color when the observer changes his or her position. As an example of this effect, the colors of oil that spread on the surface of water change when observed from different angles. These shimmering colors, which cannot be obtained even with the brightest and purest pigment colors, are very impressive. The magnificent change that occurs in colors, via even the smallest change in the angle of the light, or the position of the observer, gives these colors an amazing beauty.

The photonic structures  not only bring a shiny and striking appearance to butterfly wings, but also form versicolors that change, depending on small changes in angle. This light game is truly a visual feast. The foundation of this magnificent images that can be seen in butterflies, moths, some species of insects and the tails of peacocks, in the feathers of some birds like parrots, hummingbirds and ducks, and which are all manifestations of Almighty Allah’s name “Al-Sani” (Artist), are  based on photonic crystal structures.

Photonic Structures in Water-Dwelling Creatures

Recent research done about water-dwelling creatures have revealed the surprising complexity they possess. For example, a light-sensitive species of sea star called Ophiocoma wendtii uses photonic elements made up of calcite in order to collect light.

The same extraordinary structure is also seen in the nano-structures of the hair-like thorns of some worm species called polychaete. The two-dimensional hexagonal spaces, that look like window screens, are in every thorn  in these beings, and form a natural photonic crystal. This order generates a partial photonic effect that distributes color in various directions. As a result of this, striking colors are produced in this sea creature.

The “nano” concept defines one in one billion of physical size. For example, a nanometer is one in one billionth of a meter, and a nanometer is a measurement that is smaller than anything human senses can perceive, and is obtained by two or three atoms arranged next to one another. The perfect arrangement of photonic crystals in nature signifies an extraordinary order in the size of nanometers.

The Discovery of Photonic Structures by Science

As scientists have observed, it is possible to produce photonic crystals using semi-conductors with the help a method called “nanolithography”. It has been pointed out that light can be captured within a small space by using the irregularities formed in these structures as thin as one in tenth of the wavelength of light (30-50 nanometers). These photonic crystals, discovered towards the end of the 1980's, are structures that are shaped with an arrangement consistent with that of molecules in metallic or non-conducting substances. However, in nature these photonic structures have existed since the Cambrian period, meaning 500 million year ago. Scientists began to use photonic structures in technology in 20th Century. However, when they looked at nature, they saw that birds, insects, butterflies, sea stars have been using photonic structures, which they have begun to use just recently, for millions of years. Scientists have offered an explanation about the photonic structures being used by these beings in nature for millions of years as follows:

“Millions of years before we began to use light waves via synthetic structures, biological systems were using architectures in the size of nanometers in order to produce striking optical effects.” (Dr. Peter Vukusic and Prof. J. Roy Sambles, Thin Layer Photonics, School of Physics, University of Exeter, England)

The Colors in Nature Are the Works of Our Almighty Lord

Almighty Allah created a perfect order with photonic crystals in an area as small as one in one billionth of a meter. The striking color and patterns in living beings that use photonic structures are only one example of Almighty Allah’s infinite knowledge and art. These beings have had these colors since the first day they were created.

From the galaxies to the stars, from the infinite darkness of space to the creatures of this Earth, from the order in natural events, to the order of the human body and the wing of a butterfly, every detail in the universe clearly shows us the explicit existence of Allah, the Lord of the worlds, Who flawlessly creates the skies, the Earth and everything in between, through His infinite knowledge, artistry and intelligence. In one verse, our Lord reveals about His artistry and knowledge of creation as such:
 

“He is Allah – the Creator, the Maker, the Giver of Form. To Him belong the Most Beautiful Names.Everything in the heavens and earth glorifies Him.He is the Almighty, the All-Wise.” (Surat al-Hashr, 24)
 

Sources:

http://www.sciencedaily.com/releases/ 2006/03/060302174524.htm
http://www.sciam.com
R. C. McPhedran ve N. A. Nicorovici, Australian Optical Society News, (2001) volume 15, p. 7-9.
http://news.nationalgeographic.com