Near-field localization by ultrashort femtosecond light pulses has been investigated using simple geometrical nanoapertures. The apertures employ circular, rhombic, and triangular shapes to localize the distribution of surface plasmon. To understand the geometrical effect on the localization, aperture length and period of the nanoapertures were varied. Aperture length was shown to affect the performance more than aperture period due mainly to intra-aperture coupling of near-fields. Triangular apertures provided the strongest spatial localization below 10 nm in size as well as the highest enhancement of field intensity by more than 7000 times compared to the incident light pulse. Use of ultrashort pulses was found to allow much stronger light localization than with continuous-wave light. The results can be used for super-localization sensing and imaging applications where spatially localized fields can break through the limits in achieving improved sensitivity and resolution.
Bibliographical noteFunding Information:
This work was mainly supported by the National Research Foundation Grant funded by the Korean Government (2011-0017500 and NRF-2012R1A4A1029061). Partial support was provided by the research funds from an IITP ICT Consilience Creative Program (IITP-2015-R0346-15-1007) and an NRF Engineering Research Center grant (NRF-2011-0030075) of the Ministry of Science, ICT and Future Planning.
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