Reflectivity manipulation of silver–chromium-based multilayers

Multilayer structures with a thin chromium (Cr) layer embedded in the high reflective silver layer and dielectric layers, such as SiO2 and Ta2O5, are proposed. Reflectivity can be easily manipulated by adjusting the thickness of the Cr and dielectric layers. To demonstrate the potential for enhancing the flatness of reflection spectra, multilayers with average reflectivity value of 45% and 32% in the range of 450 to 900 nm are constructed, respectively. The reflectivity value exhibits a change of less than ±2.5%, and the transmittance is nearly negligible for both multilayer architectures. They can be fabricated using the physical vapor deposition technique.