Medical applications of hybrids made from quantum emitter and metallic nanoshell

Abstract

We have studied the photoluminescence emission in a quantum emitter and metallic nanoshell hybrid system. The metallic nanoshell is made of a dielectric core coated with a thin layer of metal and is surrounded by biological cells such as cancer cells. Surface plasmon polariton resonances in the metallic nanoshell are calculated using Maxwell's equations in the quasi-static approximation. It is found that the metallic nanoshell has two surface plasmon polariton resonances. Locations of surface plasmon polariton resonances can be manipulated by changing the size of the core and the metallic shell. We have compared our theory with the extinction coefficient of metallic nanoshells. A good agreement between theory and experiment is found. A probe laser field is applied to study the photoluminescence spectrum in the hybrid system. Dipoles are induced in the metallic nanoshell and quantum emitter due to the probe laser. Hence the quantum emitter and metallic nanoshell interact via the dipole-dipole interaction. The photoluminescence spectrum of the quantum emitter is calculated using the density matrix method in the presence of the dipole-dipole interaction. It is found that the photoluminescence spectrum of the quantum emitter with degenerate excitons splits from one peak to two or three peaks depending on the locations of two surface plasmon polariton resonances. Similarly, for the nondegenerate quantum emitter we found that the photoluminescence spectrum splits from two peaks to four peaks. These interesting findings may be useful in the fabrication of nanosensors, nanoswitches, and for other applications in medicine.