Australian scientists have developed a flat lens that's 300 times
thinner than a sheet of paper, and it has the ability to provide 3D
focus on tiny details that we currently struggle to image. This is known
as subwavelength focussing, because of its involvement in viewing objects that
are smaller than the wavelength of an individual particle of light.
This new lens could be used to build devices capable of viewing,
manipulating, monitoring, and trapping the tiniest particles in real
time. In other words, it has the potential to revolutionise the
technology used in medical diagnosis and treatment, imaging, sensing,
and even computing.
Optical lenses work by focussing light on a specific point so our
eyes can perceive it, but right now there's a limit to the size of
objects this light can be focussed on. For years scientists have been
trying to shrink down flat lenses to overcome that hurdle, but
successful concepts have all been extremely complex and hard to produce
for real-world applications.
Now a team from Swinburne University of Technology has developed a lens that's only 200 nm thick, using sprayable graphene oxide.
"Our lens concept has a 3D subwavelength capability that is 30 times more efficient, able to tightly focus broadband light from the visible to the near infrared, and offers a simple and low-cost manufacturing method," lead researcher Baohua Jia, from Swinburne’s Centre for Micro-Photonics, said in a press release.
The unique refractive index of the
material allows the lens to focus on small objects in 3D in a way that
previous lenses haven't been able to. And best of all, the process used
to make the ultra-thin lens is cheap and quick, and easily scalable.
The researchers were able to produce such a thin structure by converting
graphene oxide film into reduced graphene oxide through a
photoreduction process. And they believe that they could easily be used
in real-world devices.
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