Dynamic response analysis of pyroelectric sensitive element for thermal imaging

Temperature distributions under periodic thermal excitations and the responsivity of a pyroelectric device consisting of a cover layer, infrared absorber, metal contact, sensitive pyroelectric element, interconnecting column, and bulk silicon are found. Some results of numerical thermal modeling and analysis of exact expressions for a few extreme cases are presented. Pyroelectric responses of real structures are compared with the response of a single pyroelectric element in air as a limiting case of maximum sensitivity. The analytical approximations and numerical simulation show that the frequency response of the multilayered structure consists of different parts with simple frequency dependencies. In the region of high frequencies of light modulation, the responsivity is proportional to omega(-1), at low frequencies approximately omega(-0.5), and, in the region of intermediate frequencies, the voltage responsivity is independent of frequency.