Fano control of plasmonic double-resonant systems

Postacı, Selen
The nonlinear response of plasmonic nanostructures can be enhanced as a result of the localization of the incident field into nm-size regions, called hot spots. The Raman signal of a molecule can be enhanced by adsorbing it to the surface of a plasmonic structure. However, the hot spot enhancement is limited with the modification of the vibrational modes, the breakdown of the molecule, and transition to the tunneling regime. The analytical treatment that is presented in this study aims to circumvent these limitations by introducing the nonlinear path interference effects. Coupling a quantum emitter to the double-resonant metal nanostructure yields to path interference, enabling the further manipulation of the SERS signal. The results denote that an extra enhancement of 100-1000 factors can occur, which does not alter the existing hot spot field intensities. Besides the analytical results, 3 Dimensional solutions of Maxwell equations are also utilized in order to understand the effects of retardation on the system. In the second part, the second harmonic response of a double-resonant metal nanostructure is studied with the coupling of a quantum emitter. The quantum emitter is driven with a source where changing the pump strength enables the modification of the second converted field intensity. It is observed that as the nonlinear response of the system is enhanced, the nonclassicality measure also shows an increase. This result indicates that pumping the quantum emitter with a source provides the opportunity to modify the nonlinear response via Fano type resonances in plasmonic structures.
Citation Formats
S. Postacı, “Fano control of plasmonic double-resonant systems,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.