Open AccessComparative study of SiO_2, Si_3N_4 and TiO_2 thin films as passivation layers for quantum cascade lasers
Author(s) -
Simon Ferré,
Alba Peinado,
Enric Garcia-Caurel,
Virginie Trinité,
Mathieu Carras,
Robson Ferreira
Publication year - 2016
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.24.024032
Subject(s) - materials science , dielectric , quantum cascade laser , refractive index , passivation , laser , optics , molar absorptivity , optoelectronics , cascade , ellipsometry , wavelength , thin film , layer (electronics) , terahertz radiation , nanotechnology , physics , chemistry , chromatography
The aim of this article is to determine the best dielectric between SiO 2 , Si 3 N 4 and TiO 2 for quantum cascade laser (QCL) passivation layers depending on the operation wavelength. It relies on both Mueller ellipsometry measurement to accurately determine the optical constants (the refractive index n and the extinction coefficient k) of the three dielectrics, and optical simulations to determine the mode overlap with the dielectric and furthermore the modal losses in the passivation layer. The impact of dielectric thermal conductivities are taken into account and shown to be not critical on the laser performances.