Applied Physics

Plasmons Go the Distance

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Science  23 Jun 2006:
Vol. 312, Issue 5781, pp. 1717
DOI: 10.1126/science.312.5781.1717b

The coupling of light with electronic surface excitations—specifically, surface plasmon polaritons—offers the opportunity to bridge the orders-of-magnitude difference in sizes between optical and electronic carriers. To develop schemes for coupling and transporting surface plasmons around a chip, the determination of their propagation lengths is particularly important. In this vein, van Wijngaarden et al. have excited surface plasmons using a focused beam of electrons and then detected the luminescence emitted as the plasmons decayed. Based on these cathodoluminescence intensity decay profiles, they could determine propagation lengths as a function of wavelength. Gold and silver thin films (on silicon and quartz substrates, respectively) were patterned with gratings to direct the emission, allowing the measurement of propagation lengths as short as several hundred nanometers. The resolution of the technique is limited by excitation volume and so should increase as film thickness decreases. The authors suggest that extensions to the characterization of more elaborate plasmonic nanostructures should also be possible. — ISO

Appl. Phys. Lett. 88, 221111 (2006).

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