The Impact of the Core’s Material on the Absorption of a Quantum Dot–Metal Nanoshell Hybrid System

• Published in: Engineering proceedings 2022-12, Vol.31 (1), p.82
• Main Authors: Alexandros Kontakos, Emmanuel Paspalakis, Spyridon G. Kosionis
• Format: Article
• Language: English
• Subjects: absorption; gain; hybrid nanostructure; metal nanoshell; semiconductor quantum dot
• ISSN: 2673-4591
• DOI: 10.3390/ASEC2022-13805

In this study, we investigate the linear optical response in a hybrid nanostructure composed of a semiconductor quantum dot and a metal shell nanoparticle. We analyze a case wherein the nanostructure interacts with an incident electromagnetic field with polarization parallel to the symmetry axis of the nanosystem. We derive nonlinear density matrix equations in the rotating wave approximation under the quasistatic response of the system, and use a series expansion method to obtain analytical functions for linear susceptibility with respect to both components of the nanostructure. The imaginary part of these expressions is related to the absorption coefficient. We investigate the way in which the modification of the core’s material affects the characteristics of the spectral resonance. For low values of the dielectric constant, the system exhibits amplified gain without population inversion and quenched absorption resonance, while for high values of the dielectric constant, we observe suppression of the gain dip and enhancement of the absorption resonance. In the first regime, the exciton lifetime is suppressed, and in the second case, its value is importantly increased, especially in the case of small interparticle distances where the semiconductor quantum dot and metal shell nanoparticle interact strongly.