Ideal Detectors: Characteristics and Applications

This lecture discusses the characteristics and applications of ideal detectors in optical detection. It begins with an overview of ideal photonic detectors, focusing on shot noise limitations and the relationship between noise equivalent power (NEP) and various parameters such as bandwidth and quantum efficiency. The instructor explains how to optimize NEP by adjusting bandwidth and frequency, particularly in the context of telecommunications. The lecture then transitions to background-limited detectors, detailing the equations governing their performance and the significance of the D star parameter. The discussion includes thermal detectors, emphasizing their background limitations and the impact of temperature on detectivity. Several examples illustrate the differences between photonic and thermal detectors, highlighting the practical implications of cooling requirements for photonic detectors versus the usability of thermal detectors at room temperature. The lecture concludes with a comparison of detectivity in various detector types, underscoring the advantages of thermal detectors for applications like thermography.