Open AccessDielectric travelling wave antennas for directional light emission
Author(s) -
Till Leuteritz,
Henna Farheen,
Siqi Qiao,
Florian Spreyer,
Christian Schlickriede,
Thomas Zentgraf,
Viktor Myroshnychenko,
Jens Förstner,
Stefan Lindén
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.422984
Subject(s) - optics , refractive index , reflector (photography) , dielectric , materials science , optoelectronics , near and far field , light emission , antenna (radio) , field electron emission , substrate (aquarium) , physics , telecommunications , light source , electron , oceanography , quantum mechanics , computer science , geology
We present a combined experimental and numerical study of the far-field emission properties of optical travelling wave antennas made from low-loss dielectric materials. The antennas considered here are composed of two simple building blocks, a director and a reflector, deposited on a glass substrate. Colloidal quantum dots placed in the feed gap between the two elements serve as internal light source. The emission profile of the antenna is mainly formed by the director while the reflector suppresses backward emission. Systematic studies of the director dimensions as well as variation of antenna material show that the effective refractive index of the director primarily governs the far-field emission pattern. Below cut off, i.e., if the director's effective refractive index is smaller than the refractive index of the substrate, the main lobe results from leaky wave emission along the director. In contrast, if the director supports a guided mode, the emission predominately originates from the end facet of the director.