Scientists at Australian National University have created a lens that measures one two-thousandth the thickness of human hair. The technology will support the development of flexible computer displays and miniature cameras.
"We will also be able to use arrays of micro lenses to mimic the compound eyes of insects," said lead researcher Dr Yuerui (Larry) Lu from ANU Research School of Engineering.
The 6.3-nanometer lens uses molybedenum disulphide, a semiconducting crystal that survives at high temperatures. Previous ultra-thin flat lenses used 50-nanometer-thick gold nano-bar arrays.
Dr Lu's team used a focused ion beam to shave off layers of the crystal atom by atom, until they had the desired dome shape of the lens.
The team discovered that single layers of molybdenum disulphide, 0.7 nanometers thick, had remarkable optical properties, appearing to a light beam to be 50 times thicker, at 38 nanometers. The property, known as optical path length, determines the phase of the light and governs interference and diffraction of light as it propagates.
Collaborator Assistant Professor Zongfu Yu at the University of Wisconsin, Madison, developed a simulation and showed that light bounced back and forth many times inside the high refractive index crystal layers before passing through.
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