Nanostructured glass optics will reduce the cost of medical imaging
16 August 2011
University of Southampton researchers have developed new
nano-structured optical elements from glass that will significantly
reduce the cost of medical imaging.
A team led by Professor Peter Kazansky at the University's
Optoelectronics Research Centre, have used nano-structures to
develop new monolithic glass space-variant polarization converters.
These millimetre-sized devices generate ‘whirlpools’ of light
enabling: precise laser material processing, optical manipulation of
atom-sized objects, ultra-high resolution imaging and potentially,
table-top particle accelerators. They have since found that the
technology can be developed further for optical recording.
New monolithic glass space-variant polarization
According to the researchers, at sufficient intensities,
ultra-short laser pulses can be used to imprint tiny dots (like 3D
pixels) called voxels in glass. Their previous research showed that
lasers with fixed polarization produce voxels consisting of a
periodic arrangement of ultra-thin (tens of nanometers) planes.
By passing polarized light through such a voxel imprinted in
silica glass, the researchers observed that it travels differently
depending on the polarization orientation of the light. This ‘form
birefringence’ phenomenon is the basis of their new polarization
The advantage of this approach over existing methods for
microscopy is that it is 20 times cheaper and it is compact.
"Before this we had to use a spatial light modulator based on
liquid crystal which cost about £20,000," said Professor Peter
Kazansky. "Instead we have just put a tiny device into the optical
beam and we get the same result."
Since publication of the paper in May this year, the researchers
have developed this technology further and adapted it for a
five-dimensional optical recording.
"We have improved the quality and fabrication time and we have
developed this five-dimensional memory which means that data can be
stored on the glass and last forever," said Martynas Beresna, lead
researcher for the project. "No one has ever done this before."
The researchers are working with the Lithuanian company Altechna
to introduce this technology to the market.
Martynas Beresna, Mindaugas Gecevičius, Peter G. Kazansky, and
Titas Gertus. Radially polarized optical vortex converter
created by femtosecond laser nanostructuring of glass. Applied
Physics Letters. 98, 201101 (2011); doi:10.1063/1.3590716