Using high accurate infrared spectroscopic ellipsometry, the infrared dielectric constants of BaTiO<sub>3</sub> ultrathin films are
obtained in the temperature ranging from 20 to 150°C, which were deposited on Pt-Ti-SiO<sub>2</sub>-Si substrate by radio
frequency magnetron sputtering. The high frequency dielectric function of the BaTiO<sub>3</sub> ultrathin films shows the
temperature dependence from the tetragonal to the cubic phase transition. The results suggest that the temperature
dependence of the BaTiO<sub>3</sub> ultrathin films' infrared dielectric properties should be considered in the technological
applications and theoretical investigations.
Hybrid barium strontium titanate (BST) ferroelctric detectors still provide the basis for the majority of uncooled infrared systems being produced today. Considering the complexity of the hybrid BST detector fabrication process, monolithic BST thin-film dielectric bolometers allure the researchers. For the micro-bridge thermal isolation structure, the performances of single pixel of BST thin-film dielectric bolometer mode of uncooled infrared focal plane arrays (IRFPA) are computed by thermal diffusion equation.