Pyroelectric Detectors: Applications and Mechanisms

This lecture discusses the applications and mechanisms of pyroelectric detectors, focusing on thin-film pyroelectric sensors. The instructor explains the structure of these detectors, which consist of a substrate, a cavity, and a pyroelectric crystal placed between metallic electrodes. The current generated by infrared radiation is measured, highlighting the importance of the absorbing layer. The lecture also covers the use of pyroelectric cameras and their components, including readout electronics and micro-machining techniques. Motion detection is explored, detailing how intruders can be detected through variations in infrared radiation. The instructor presents advanced solutions such as dual pyroelectric sensors and interdigitalized structures to enhance detection capabilities. A comparison of different thermal detectors is made, emphasizing their performance in mid and far infrared detection. The lecture concludes with remarks on the advantages of thermal detectors, particularly their ability to operate at room temperature, while noting the superior sensitivity of photonic detectors that require cooling.