Open Access
Design, fabrication and characterization of a distributed Bragg reflector for reducing the étendue of a wavelength converting system
Author(s) -
Boxuan Gao,
John P. George,
Jeroen Beeckman,
Kristiaan Neyts
Publication year - 2020
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.391080
Subject(s) - materials science , optics , fabrication , refractive index , distributed bragg reflector , wavelength , spectrometer , optoelectronics , ellipsometry , thin film , nanotechnology , medicine , physics , alternative medicine , pathology
In this work, the design, fabrication and characterization are reported for a distributed Bragg reflector (DBR) filter with a specific wavelength and angular dependency, which aims to improve the light collection from a wavelength-converter-based light source into a smaller angle than the full angle Lambertian emission. The desired design is obtained by optimizing the transmission characteristics of a multi-layer structure. Titania (TiO 2 ) and silica (SiO 2 ) are used as high and low refractive index materials, respectively. The deposition is made by electron beam evaporation without substrate heating, followed by a post-annealing procedure. The optical properties of the evaporated layers are analyzed by ellipsometer and spectrometer measurements. The angular and wavelength dependency of the fabricated DBR is in good agreement with simulations for the designed structure.