Greatly amplified spontaneous emission of colloidal quantum dots mediated by a dielectric-plasmonic hybrid nanoantenna

Guoce Yang,Yijie Niu,Hong-Bo Sun,Benfeng Bai,Hong Wei

doi:10.1515/nanoph-2019-0332

Abstract

Abstract Optical nanoantennas can efficiently harvest electromagnetic energy from nanoscale space and boost the local radiation to the far field. The dielectric-metal nanogap is a novel design that can help to overcome the core issue of optical loss in all-metal nanostructures while enabling photon density of states larger than that in all-dielectric counterparts. This article reports that a crystalline spherical silicon nanoparticle on metal film (SiNPoM) nanoantenna can largely enhance the spontaneous emission intensity of quantum dots by an area-normalized factor of 69 and the decay rate by 42-fold compared with quantum dots on glass. A high total quantum efficiency of over 80%, including ~20% for far-field radiation and ~60% for surface plasmon polaritons, is obtained in simulation. Thanks to not only the low optical loss in dielectric nanoparticles but also the appropriate gap thickness which weakens the non-radiative decay due to the quenching from metal. Mie resonant modes additionally provide the flexible control of far-field emission patterns. Such a simple optical nanoantenna can be combined with various nanoscale optical emitters and easily extended to form large area metasurfaces functioning as active regions in light-emitting devices in applications such as advanced display, wireless optical communication, and quantum technology.

Highlights

Spontaneous emission as a fundamental optical process has recently attracted great interest due to its potential application in various fields such as optical interconnection [1], optical wireless communication [2, 3], and quantum technology [4]
We propose an effective solution to address the above two key concerns with a silicon nanoparticle on metal film (SiNPoM) antenna consisting of a crystalline spherical silicon nanoparticle
In the SiNPoM system, the sizes of CdSe/ZnS quantum dots are ~10 nm and the crystalline SiNPs are prepared by femtosecond laser ablation in liquid and the diameters are from 80 to 200 nm [32]

Summary

Introduction

Spontaneous emission as a fundamental optical process has recently attracted great interest due to its potential application in various fields such as optical interconnection [1], optical wireless communication [2, 3], and quantum technology [4]. This article reports that a crystalline spherical silicon nanoparticle on metal film (SiNPoM) nanoantenna can largely enhance the spontaneous emission intensity of quantum dots by an area-normalized factor of 69 and the decay rate by 42-fold compared with quantum dots on glass.

Results

Conclusion