Growing structures at the nanoscale is one of the most difficult and pressing problems holding back nanotechnology. New ways have to be found to control complex arrangements of different atoms inside materials with novel functionality, avoiding expensive traditional fabrication methods. Using light to control growth is a highly promising new advance.
Current Work
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Optical growth of Ge nanowires
Laser irradiation and selective absorption is used to locally heat and trigger reactions on individual catalyst nanoparticles in a gaseous precursor atmosphere. Confining light to tiny metallic nanostructures allows us to control and study nanowire growth processes in real-time using optical spectroscopy at the individual nanoparticle level.
Key paper: Di Martino et al., Nano Letters 15, 7452 (2015)
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Optical growth of conducting bridges
Confining light to the nanometre scale produces enormous optical forces in nanoscale gaps. We use this to move gold atoms around by light, rewiring plasmons in real time.
Key paper: Mertens et al., Nano Letters (2016)
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Previous Work
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Optical growth of carbon nanotubes
By focussing intense lasers onto nanoparticle catalysts in a thin gas of acetylene, we use light to grow carbon nanotubes selectively at any position on a substrate. This completely new way to grow nanostructures opens up the possibility of delicately controlling growth at the smallest scales. |
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Optically written arc waveguides Light is normally injected into photonic circuits on a chip from the side, which makes them expensive to make and difficult to align. Using short pulses of light, absorbed two photons at a time, to directly write structures in polymers, we make any shape of optical waveguide that can couple light from the top into any direction. |
References
[2] “Optical feedback mechanisms in laser-induced growth of carbon-nanotube forests”, Appl.Phys.Lett. 100, 013112 (2012)
[1] “Perpendicular coupling to in-plane photonics using arc waveguides,” Appl.Phys.Lett. 100 171102 (2012)