Double-Pointed Optical Antenna in the Longwave Infrared (LWIR) Spectral Regime

Photonic antennas provide an effective approach for the light receiving with engineerable near fields and receiving gains. Various antennas such as dipole, bow-tie, circular disk, circular ring, and pointed-dipole antenna have been reported with an enhancement to infrared detection. In this paper, we report a new double-pointed optical antenna and its enhancement in the longwave infrared (LWIR, 8-12 μm or 25 tera-Hz to 37.5 tera-Hz) spectral regime. The double-pointed photonic antennas are simulated and compared with the single-pointed dipole antenna. It is found that the double-pointed photonic antennas show higher E-fields in the LWIR spectral regime for both the single antenna or coupled antenna configurations. The uncoupled double-pointed dipole antenna can be modeled as an RLC circuit, whereas the coupled double-pointed dipole antennas show clear Fano-type interference between the transmission and the discrete plasmonic resonant modes. The E-fields of the double-pointed antenna are also compared to those of the bow-tie antenna with the same gap dimension.