Low-loss one-dimensional metallodielectric photonic crystals fabricated by metallic insertions in a multilayer dielectric structure

Abstract

Low-loss one-dimensional metallodielectric photonic crystals were obtained by inserting Ag layers into ZnS/MgF2 quarter-wave multilayers. They were fabricated by thermal evaporation of ZnS, MgF2, Ag, and MgF2 layers alternately onto a glass substrate. For a sample of 3.5 periods of ZnS (61.7 nm)/MgF2 (52.5 nm)–Ag (19 nm)–MgF2 (52.5 nm), the transmittance spectrum shows a wide and deep band gap between 420 and 790 nm with rejection level of 10 dB per lattice. Above 790 nm, there is a 210 nm wide high passband. The transmittance at the bandedge is about 60%. Its reflectance spectra over an incident angle range of 10°–70° show a 240 nm wide low-loss omnidirectional high reflection band for both p and s polarizations. All the experimental measurements match well with the theoretical results calculated by the transfer matrix method.