Abstract

Light and surface plasmons can be slowed down by means of photonic and plasmonic crystals, respectively. One of the key advantages of such photonic nanostructures over alternative ‘slow light strategies’ is that they can achieve an appreciable slow down while maintaining a high bandwidth. With a unique phase-sensitive and time-resolved near-field microscope slow optical fields can be tracked through a structure on a femtosecond timescale. We have observed light fields that have a speed of, at most, c/1000. We are able to experimentally determine the photonic or plasmonic band structure, facilitating dispersion engineering which is necessary to reap the benefits of slow light. Ultrafast investigations in reciprocal space enable the dynamics of photonic/plasmonic eigenstates to be unravelled even when several are co-localized in space and time.

References

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