The effect of high reflectance metallic thin films of reference mirror layers is investigated using three different thin film structures on sapphire substrate: the sapphire/Ti/Ag/AuSn, sapphire/Cr/Ag/AuSn, and sapphire/Al2O3/Ag/AuSn structures. Various co The effect of high reflectance metallic thin films of reference mirror layers is investigated using three different thin film structures on sapphire substrate: the sapphire/Ti/Ag/AuSn, sapphire/Cr/Ag/AuSn, and sapphire/Al2O3/Ag/AuSn structures. Various co