Scientist Changes color of Gold,Platinum & Silver

Using the technique of intense laser light, optical scientists at the University of Rochester in US have been able to change the colour of some metals to create variations like gold aluminum, black platinum and blue silver.

What this technique originally does is that it alters the properties of a variety of metals to render them pitch black.

This was observed in late 2006, when researchers created nano structures on metal surfaces that absorbed virtually all light, making something as simple as regular aluminum into one of the darkest materials ever created.

Now, the process has been further pushed to make it possible for metals to be turned into any colour—even multi-coloured iridescence like a butterfly's wings.

As part of the procedure, Guo and his assistant, Anatoliy Vorobeyv, used an incredibly brief but incredibly intense laser burst that changes the surface of a metal, forming nanoscale and microscale structures that selectively reflect a certain colour to give the appearance of a specific color or combinations of colours.

Guo and Vorobyev also achieved the iridescent colouring by creating microscale lines covered with nanostructures. The lines, arranged in regular rows, cause reflected light of different wavelengths to interfere differently in different directions.

The result is a piece of metal that can appear solid purple from one direction, and gray from another, or multiple colours all at once. They changed the color of some metal to gold which made them to develop this process to other metals also.

According to Guo, the new process has worked on every metal that the research team has tried, and the results are so consistent that he believes it will work for every metal known.
His team is currently working to find the right tuning to create the rest of the rainbow for the solid-coloured metal, including red and green.

This technique might further lead to applications ranging from making better solar energy collectors, to more advanced stealth technology.