High-efficiency, low-cost distributed Bragg reflector based on Al2O3/PbZr0.4Ti0.6O3 multilayer

Ferroelectric oxides are kinds of materials for construction of tunable photonic crystals with remarkable electro-optical properties. However, it is a challenge to prepare high quality dielectric mirrors consisting of ferroelectric and dielectric materials. Herein, we report a simple and inexpensive PVP-based sol-gel technique for fabricating crack-free Al2O3/PbZr0.4Ti0.6O3 (PZT) Bragg reflectors. A high-reflection band with a 200-nm bandwidth and an average optical reflectivity of more than 75% is achieved by a periodic stack of only four Al2O3/PZT bilayers, making the multilayer structure potentially applicable in tunable dielectric mirrors, optical cavities, and selective filters.