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FLEXIBLE computer displays and revolutionary miniature cameras are a possibility, thanks to the world’s thinnest lens.
Created by scientists from the ANU Research School of Engineering, the lens is one two-thousandth the thickness of a human hair, at 6.3nm.
The key to the remarkable thinness of this lens is due to the material it is made of: molybdenum disulphide crystal.
Previous ultra-thin flat lenses were made from 50nm thick gold nano-bar arrays.
Molybdenum disulphide survives at high temperatures, is a lubricant, a good semiconductor and can emit photons too.
It has also a very high refractive index, at 5.5, meaning it has a major effect on light. Comparatively speaking, diamond has a 2.4 refractive index, and water’s is 1.3.
This high refractive index means that to light, molybdenum disulphide crystals appear much thicker.
Single atomic layers of molybdenum disulphide, which measure just 0.7nm thick, appear to a light beam to be 50 times thicker, at 38nm. This property allows a 9 atomic layer thick, 6.3nm piece of crystal, to effectively work as a lens.
The researchers peeled the raw material for the lens off a larger piece of molybdenum disulphide with sticky tape.
They then created a 10-micron radius lens, using a focussed ion beam to shave off the layers atom by atom, until they had the dome shape of the lens.