Gallium lanthanum oxysulfide (GLSO) is a promising host material for observing strong upconversion emission from trivalent rare-earth ions such as erbium (Er³⁺). Its attractive properties include high rare-earth solubility due to the lanthanum content of the glass former, a high refractive index (n = 2.2 at 550nm) for high radiative efficiency, and a low maximum phonon energy of approximately 425cm ^-1. Photonic crystals meanwhile can provide controlled light extraction, and may be capable of suppressing unwanted IR emission from lower lying metastable states. Here, we describe the fabrication of photonic crystals in annealed films of Er³⁺-doped GLSO deposited by RF sputtering. The most intense visible upconversion emission is observed in films annealed at 550°C, close to the bulk glass transition temperature. Hexagonal lattice photonic crystals are subsequently milled into the films using a focused ion beam (FIB). The milling parameters are optimized to produce the most vertical sidewall profile.

Date Published: 20 March 2012
PDF: 10 pages
Proc. SPIE 8257, Optical Components and Materials IX, 82570V (20 March 2012); doi: 10.1117/12.908014

Published in SPIE Proceedings Vol. 8257:
Optical Components and Materials IX
Shibin Jiang; Michel J. F. Digonnet; J. Christopher Dries, Editor(s)