Self-assembling ‘perfect mirrors’ could pave the way for optical computers

Developed by chemical engineers at Purdue University in the U.S., the technique works by attracting tiny, floating particles into forming the desired structure in a silicon template. The technique is expected to be faster and less expensive than current processes that are commonly used in the semiconductor industry.

Already, the self-assembly technique has been used to create a precisely ordered two-dimensional layer of particles, which is called a colloidal crystal. These single-layer structures may be used to form “micro lenses” that researchers expect to improve the performance of optical equipment in cameras and other consumer products.

The next step is to grow three-dimensional crystals for the development of “omni-directional photonic band gap materials”, which are mirrored materials capable of reflecting certain wavelengths of light coming from all directions. Such materials currently are prohibitively expensive to manufacture, although they would vastly improve the capabilities of optical fibres.

"We envision that this self-assembly method will open a new possibility for mass fabricating complicated 3-D colloid crystal structures for various applications," said You-Yeon Won, an assistant professor of chemical engineering who is researching the technique at Purdue.

"Making the first layer is very difficult, so we have taken an important step in the right direction. Creating three-dimensional structures poses a big challenge, but I think it's feasible."

In a similar vein to Leonardo Da Vinci’s fabled dream of scientifically turning carbon into gold, the Purdue researchers expect the self-assembly technique to one day produce diamonds.

"There is no conventional technology that allows you to easily fabricate the diamond-crystal structure, so our method could open the door to doing so," Won said.

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