Pyroelectric voltage response to step signals of infrared radiation in triglycine sulphate and strontium-barium niobate

Theoretical and experimental analysis of voltage transients obtained in triglycine sulphate and strontium-barium niobate in response to step radiation signals yields information important for pyroelectric ir detection. The response transients are shown to be symmetrical with respect to the electronic and thermal time constants τ_e and τ_T of the samples. When τ_e and τ_T differ appreciably, the rise of the response and its decay are exponentials whose time constants are, respectively, the smaller and the larger one from among τ_T and τ_e. The peak voltage values are proportional to the load resistance R_L when τ_e≪τ_T; they become independent of R_L and proportional to τ_T when τ_e≫τ_T. The initial slope of the response in a given sample is found to be independent of R_L for a given radiation flux. The pyroelectric coefficient of a material, divided by the product of its permittivity, density, and specific heat is shown to be a figure of merit for use in pyroelectric ir detection