Active magnetoplasmonics for nanoscale distances sensing

Licentiatavhandling, 2015

Magnetoplasmonics is an emerging field within nano-photonics that operates with the combination of propagating or localized surface plasmons and magnetism. Active and adaptive magnetoplasmonic components that are capable of controlling light on the nanoscale with external weak magnetic fields are envisioned to push the development of integrated photonic circuits, high-density data storage, or the advanced schemes for bio- and chemo-sensing. In these components plasmon-enhanced and controlled magneto-optical activity creates a new way of active control of plasmonic devices. In this thesis we investigate the role of localized surface plasmons on magneto-optical activity and demonstrate how magnetoplasmonics can be employed in the optical detection of nanoscale distances. Plasmon rulers are an emerging concept in which the strong near-field coupling of plasmon nanoantenna elements is employed to obtain structural information at the nanoscale. We introduce an active magnetoplasmonic ruler that provides active operation and nanoscale distances reading with the figure-of-merit substantially exceeding the one of traditional plasmon rulers. We combine nanoplasmonics and nanomagnetism to conceptualize a magnetoplasmonic dimer nanoantenna that would be able to report nanoscale distances while optimizing its own spatial orientation. The latter constitutes an active operation, in which a dynamically optimized optical response per measured unit length allows for the measurement of small and large nanoscale distances with about two orders of magnitude higher precision than current state-of-the-art plasmon rulers.