Sputtered silica defect embedded in artificial opals: Synthesis and optical properties

Summary form only given. Applications of 3D-photonic crystals like low-threshold lasers and control of the fluorescence properties of embedded quantum emitters require in most cases, insertion of a controlled defect inside the structure. Indeed, the disruption of the photonic crystal periodicity can create permitted optical frequencies bands within the photonic bandgap: light whose frequency is included in the corresponding passband is then localized in the defect allowing effects such as waveguiding and confinement. Artificial opals are 3D photonic crystals, whose synthesis is based on self-assembly of dielectric spheres. In order to obtain light confinement inside opals, several fabrication methods have been used to create a defect [1].We propose here an original, efficient and reliable method, based on the sputtering of a controlled amount of silica, to engineer a defect between two silica opals. Transmission and specular reflection spectra were performed to characterize the optical response of our samples. Tunable and highly transmitted and reflected optical modes, in good agreement with Finite Difference Time Domain simulations, were evidenced.