Design, simulation, and fabrication of longitudinal electrooptically tuned transparent-comb-electrode photonic crystals

Abstract

We designed advanced transparent-comb-electrode photonic crystals (TCE PCs) to use the longitudinal electro-optic (LEO) effect, so they are composed of Al-doped ZnO (AZO) layers, which serve as internal/external electrodes, and centered (Pb,La)(Zr,Ti)O3 (PLZT) layers, which serve as EO material. The simulated transmittance spectra of a multilayer interference (MLI) model revealed the conditions in the AZO and PLZT film thicknesses and the AZO/PLZT period number for a narrow photonic band gap (PBG). The TCE PCs consisted of four periods of AZO/PLZT, and it was fabricated by RF magnetron sputtering through metal mask patterning. Finally, a refractive index change induced by the LEO effect of the PLZT layers was accomplished by applying the voltage dependence of transmittance spectra that were well fitted with a revised (MLI) model considering light absorption and scattering. The PCs exhibit large refractive index changes of 1.3 × 10-2 and 2.9 × 10 -2 at DC voltages of 4 and 8V, respectively. The corresponding PBG shifts were 3.9 and 8.5 nm, implying high a PBG tunability of ∼1nm/V. © 2013 The Ceramic Society of Japan.