Recently, plasmonics, utilizing excitation and propagation of surface plasmon polaritons in metallic nano- and micro-structures, has been identified as a possible way for bypassing optical diffraction limits in small photonics systems. The progress in this field goes hand in hand with technology developments and fabrication of photonic structures exhibiting unique and novel properties.
In our contribution the results on fabrication of plasmonic antennas suitable for local resonance excitation of electromagnetic fields by two distinct techniques, focused ion beam (FIB) and electron beam lithography (EBL), will be presented. FIB and EBL have been carried out by commercial facilities (FEI, Raith) available at the Stanford Nanocharacterization Laboratory and Stanford Nanofabrication Facility, respectively. The dimensions of the antennas were tuned mostly for resonances in the mid infrared region possessing smallest design features around 100 nm, but to find the limits of the applied techniques some test antennas elements (< 100 nm) for the visible spectral region were built as well. The antennas were made of platinum, to withstand enhanced temperatures, both on insulating (quartz) and semiconductive (Si) surfaces and their geometrical parameters analysed by SEM and AFM. The comparison of the results achieved by both techniques and their pros and cons will be discussed.
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