Lecture
This lecture presents a comprehensive overview of thermal detectors, focusing on their general model and fundamental principles. The instructor begins by discussing the basic components of a thermal detector, including the probe that receives infrared optical power and the thermal reservoir that maintains a fixed temperature. Key concepts such as thermal conductivity, heat capacity, and power dissipation are introduced, along with mathematical equations that describe the heat variation in the probe. The relationship between sensitivity, bandwidth, and thermal properties is explored, highlighting the trade-offs between sensitivity and response time. The lecture also covers heat fluctuations, noise equivalent power (NEP), and the ultimate limits of thermal conductivity, emphasizing the impact of blackbody radiation. The instructor concludes by discussing the practical implications of these concepts in various applications, including thermography. Overall, this lecture provides a detailed understanding of the principles governing thermal detectors and their performance characteristics.