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Infrared detection devices are becoming miniature with micro or nano-scale size. The advantages of downsizing come on the expense of insufficient collection of infrared radiation. Therefore, utilizing nano-plasmonic optical antennas becomes mandatory. However, it is desirable to develop antennas with broad bandwidth, polarization insensitivity, wide field-of-view, and reasonable plasmonic losses in order to collect most of incident infrared radiation and enhance power absorption efficiency. Here, an innovative optical antenna (optenna) is proposed and demonstrated for the first time. It has a novel shape of Bundt baking-pan. The gold Bundt is arranged in a periodic array that can be placed on top of a thin-film infrared absorbing layer. The developed optenna can squeeze infrared electric and magnetic fields to 50 nm-wide area in order to enhance material absorption efficiency. It demonstrates polarization insensitivity and ultra-broad bandwidth with a large fractional-bandwidth within the near, shortwave, and midwave infrared bands. It shows a remarkable enhanced power absorption efficiency up to 8 orders of magnitude with a reasonable average power loss of −3 dB and 80° field-of-view. It can be promising for future applications in solar-cells, telecommunication photodetectors, shortwave cameras, and midwave microbolometers.

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A localized nanoplasmonic induced absorption enhancement in silicon nitride ðSi 3 N 4 Þ dielectric material using a nanoscale novel checkerboard gold (Au) structure is demonstrated. The checkerboard structure is fabricated on a Si 3 N 4 layer using electronbeam lithography and sputter deposition techniques. The plasmonic electric field and optical absorption enhancement are measured using scanning near-field optical microscopy. Finite-difference time-domain simulations are utilized to characterize the absorption spectral response enhancement together with its dependence on incidence angle and polarization. The checkerboard shows a broadband average spectral absorption enhancement of 63.2% over the wavelength range 8-12 m with a maximum enhancement of 107% at 8 m and a minimum enhancement of 24.8% at 12 m. The degradation of enhanced absorption with incidence angle variation (0 -60 ) is less than 1.6% at 10.6-m wavelength. The checkerboard device shows polarization-independent absorption enhancement with incidence angles.