Biomimetic nano-antenna arrays: A concept for designing sub-wavelength angle-sensing detectors at optical wavelengths

Biologically-inspired coupled antenna arrays that mimic the hyperacute sense of directional hearing of certain insect species have recently been reported and several prototypes of such antennas have been experimentally characterized at microwave frequencies. In this paper, the concept of a two-element biomimetic antenna array is extended to optical frequencies and a new design for a two-element nano-antenna array that can act as a sub-wavelength angle-sensing optical detector is presented. The main feature of the proposed sub-wavelength detector is that it can be used to perform angle sensing without the need to perform coherent measurements at optical frequencies. This is particularly important at infrared and optical frequencies where conducting phase coherent measurement is challenging. The principles of operation of the new nano-antenna array along with the design and simulation results of a prototype are presented and discussed in this paper.