Fig. 4From: Tunable Optical Performances on a Periodic Array of Plasmonic Bowtie Nanoantennas with Hollow CavitiesBehaviors of the near-field intensities (a–c) and absorption spectra (d–f) vs. wavelengths affected by the filling medium inside the hollow region of PBNAs with different ε (ε = 1.00, 1.77, 2.31, 2.66, and 3.06)Back to article page