Active tuning of ENZ resonances in a meta-antenna through phase modulation of an optical pulse

Plasmonic nanoantennas offer new avenues to manipulate the propagation of light in materials due to their near field enhancement and ultrafast response time. Here we investigate the epsilon-near-zero (ENZ) response in an L-shaped nanoantenna structure under the phenomenon of plasmonic analog of enhancement in the index of refraction. Using a quantum mechanical approach, we analyze the modulation in the response of L-shaped nanoantenna and emergence of ENZ frequency region both in the linear and nonlinear plasmonic system. We also demonstrate the active tuning of ENZ frequency in a nanoantenna structure by modulating the phase of control pulse. The analytical and 3D FDTD simulation results show a significant spectral shift in the ENZ modes, conveniently. Our proposed method offers the possibility to design and control optical tunable ENZ response in plasmonic metasurfaces without the use of meta-material. Such metasurfaces can be used in on-chip photonic integrated circuits, further localization of incident fields, slow/fast light operations and various quantum technologies.