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To study laser interactions with materials and develop laser
microprocessing and nanofabrication techniques for industrial applications.
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Since
its inception just over a decade ago, the Data Storage Institute
(DSI), formerly known as the Magnetics Technology Centre (MTC),
has collaborated with the NUS ECE Department in basic research.
This close synergistic collaboration has brought about many successful
innovations for industry. The Laser Microprocessing Laboratory is
one of the earliest joint labs established by the ECE Department
and DSI.
With the areas of collaboration burgeoning over
the years, this year has seen progress in two projects in
particular.
Carbon nanoparticles generation by laser
ablation in solution
Nanomaterials have many unique physical and chemical
properties and research groups are putting a lot of effort into
growing different nanomaterials by CVD, sputtering and laser ablation
techniques. In this research project, glassy carbon is put inside
a solution and irradiated with high power short pulse laser which
induces laser ablation of the substrate materials. Generated plasma
is confined in the
solution. Fast quenching of laser-ablated materials leads
to carbon nanomaterials generation.
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Figure (top left) is a TEM image
of carbon nanoparticles generated with a diameter of around 20nm.
This type of nanomaterial has excellent optical limiting property
compared with C60 nanomaterials and can be used to make optical
isolators in optical communication and protective goggles.
Ultrashort femtosecond laser microfabrication
of bio-structures on Teflon substrates
Teflon, a bio-compatible material, is anti-adhesive
and hydrophobic and widely used in medical science as a substrate
material for bio-implantation micro-devices.
Electro-discharge machining cannot be used to produce the micro-devices
on Teflon substrate since it requires the substrate material to
be an electrical conductor. Its special light absorption characteristics
limit the use of conventional lasers in the surface microfabrication.
In this project, ultrafast femtosecond (fs) laser is applied to
ablate Teflon substrates with non-linear and multi-photon absorption.
With optimal control laser processing parameters, fine processed
edge can be obtained. Figure (bottom left) shows a bio-structure
created on Teflon by fs laser irradiation. |
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