Nanoantenna arrays combining enhancement and beam control for fluorescence-based sensing applications

This paper presents measured fluorescence enhancement results for ∼250×250 element aluminum nanoantenna arrays fabricated using electron beam lithography. The arrays have been designed to use diffractive coupling to enhance and control the direction of fluorescent emission. Highly directional emission is obtained at the designed angles with beam widths simulated to be in the range of 4-6°. Angle-resolved spectroscopy measurements of dye-coated nanoantenna arrays were in good agreement with finite difference time domain modeling. Critically, these results were obtained for near UV wavelengths (∼360  nm), which is relevant to a number of biosensing applications.