Directional emission of nanoscale chiral sources modified by gap plasmons

TL;DR

This paper presents a method to control the emission direction of nanoscale chiral light sources using gap plasmons, achieving high directionality and enhanced emission rates for applications in photonics.

Contribution

The study introduces a novel gap plasmon-based scheme for directional control of chiral emission at the nanoscale, with tunable configurations and high contrast ratio.

Findings

Achieved 99.5% contrast ratio in directional emission

Demonstrated tunability by adjusting nanostructure parameters

Enhanced emission rates within the nanogap

Abstract

Efficient manipulation of the emission direction of a chiral nanoscale light source is significant for information transmission and on-chip information processing. Here, we propose a scheme to control the directionality of nanoscale chiral light sources based on gap plasmons. The gap plasmon mode formed by a gold nanorod and a silver nanowire realizes the highly directional emission of chiral light sources. Based on the optical spin-locked light propagation, the hybrid structure enables the directional coupling of chiral emission to achieve a contrast ratio of 99.5%. The emission direction can be manipulated by tailoring the configuration of the structure, such as the positions, aspect ratios, and orientation of the nanorod. Besides, a great local field enhancement exists for highly enhanced emission rates within the nanogap. This chiral nanoscale light source manipulation scheme provides a way for chiral valleytronics and integrated photonics.