The fine spectral tuning of plasmon mode and quantum emitter coupling and its comparison with the dark-hot resonances

Abstract

Localization of incident fields into very small volumes (hot-spots) allows strong light-matter interactions at the hot spots. This makes path interference effects, Fano resonances, visible. Fano resonances can appear due to the coupling of a bright plasmon (i) to a longer lifetime dark plasmon mode or (ii) to a quantum object (QO) of a much longer lifetime. The second phenomenon provides a very important utility: the voltage tunability of the linear/nonlinear response. The level-spacing of the QO, such as defect-centers and quantum dots, are voltage-tunable which can make a sharp Fano resonance appear and disappear. Here, we compare the two phenomena by solving the equations of motions for the near-field plasmon amplitudes, derived from two different Hamiltonians. While the two plasmon amplitudes look similar to each other, except for the population inversion parameter 'y', our results show that quantum emitter enables fine spectral tuning of the plasmon amplitude, thus, providing better enhancement.