TITLE:
Opal-Based Photonic Crystal Heterostructures
AUTHORS:
A. Chiappini, C. Armellini, N. Bazzanella, G. C. Righini, M. Ferrari
KEYWORDS:
Sol-Gel; Colloidal Crystals; Optical Properties; Heterostructures
JOURNAL NAME:
Optics and Photonics Journal,
Vol.2 No.3A,
September
28,
2012
ABSTRACT: The fabrication of photonic crystal heterostructures is important for the applications in the fields of integrated photonic crystal chips and multi-frequency optical Bragg filters or mirrors; here we report on the fabrication and characterization of opal-based photonic crystal heterostructures. These heterostructures are created by using multilayer deposition of silica and polystyrene spheres. In the specific the fabricated structures involved both different lattice constant and dielectric function. Scanning electron microscopy (SEM) and VIS-NIR transmittance and reflectance spectroscopy are used to characterize the systems. The SEM images show good ordering of the two-layer colloidal crystals constituting the heterostructures. The transmittance and reflectance spectra measured from the (111) plane of the heterostructure show that the composite colloidal photonic crystals have double photonic stop bands that matches the stop bands of the individual photonic crystals. This behaviour can be seen as a superposition of the properties of each individual layer.