Researchers at the University of Missouri in the US have shown how surface plasmon resonance (SPR)-based fluorescence amplification platforms can be produced at very low cost by using features found in commercially available HD-DVDs as a starting mold. The group reports that the discs, which come pre-fabricated with sub-micron-sized grating patterns, have the right dimensions to couple surface plasmons in the visible range.
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| Sensing platform: plasmonic gratings fabricated using HD-DVDs |
Nano-gaps are important
In the study, the scientists used a simple PDMS-based microcontact printing/replication process to reproduce the surface features of an HD-DVD-R disc (dissected into two parts to reveal the grating pattern on the inner side of the polycarbonate substrate) on conventional glass substrates. An important consequence of the fabrication process was the generation of defects in the form of nano-gaps that cut across the printed gratings.
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| Nanogap |
The presence of nanogaps within the grating structures led to substantial field localization and amplification – propagating surface plasmon polaritons (SPPs) travel as surface waves with high field intensity towards the metallic nanogap where the sudden field discontinuity causes “extreme crowding” of the surface charges, leading to very high field intensities.
Nanotech Web Lab Talk:
HD-DVDs provide low-cost starting mould for fabricating plasmonic gratings
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