Understanding Ideal Detectors: Theory and Applications

This lecture focuses on the theory of ideal detectors in optical detection. It begins by defining what constitutes an ideal detector, emphasizing the assumption that all internal noise sources are negligible. The instructor discusses the impact of shot noise from both the signal and background, explaining how these factors influence detector performance. The lecture categorizes detectors into photonic and thermal types, detailing their respective limitations under different noise conditions. The instructor presents mathematical models to calculate signal-to-noise ratios for various scenarios, including photonic detectors limited by shot noise and background noise, as well as thermal detectors. The discussion includes the significance of responsivity and noise equivalent power (NEP) in determining detector efficiency. The lecture concludes with a comparison of NEP across different detector types, highlighting the relationship between detector characteristics and their operational environments. Overall, this lecture provides a comprehensive overview of ideal detector theory, essential for understanding advanced optical detection systems.