Ultra-fast non-linear optical property of plasmonic and metamaterials

In this project, we propose to design plasmonic metamaterials with two Fano- resonant bands for enhancing the nonlinear processes. The first band is designed with to resonate when pumped with laser in the wavelength range: ~ 1.2 - 1.4 μm. At the resonant wavelength, pumped energy would be strongly localized in the metamaterial device, thus enhancing the nonlinear optical process and the induced refractive index change is expected to be maximized. The second Fano-band is designed with broadband resonance that corresponds to the wavelength of probe laser (from super-continuum light source with wavelength: 1.5 μm to 1.7 μm). The resonant nature at the second Fano-band is amplifying the sensitivity of transient reflection of the probe signals. Thus, the two Fano-resonant bands are aligned to the pump and probe laser simultaneously and the two Fano-resonant bands can be tuned separately. This design provides us greater freedom to realize tunable metamaterial for ultrafast optical switching. In addition, as third harmonic generation (THG) radiation is in the visible range, i.e. it has faster dephasing time than the transient reflection process, it can be used to monitor the ultrafast interaction between the pump laser and the probe signal.