Light-Matter Interactions: Optical Detectors Overview

This lecture covers the fundamental principles of light-matter interactions, focusing on absorption and emission processes in optical detectors. It begins with an introduction to light waves and photons, explaining the basic concepts of spontaneous and stimulated emission, as well as absorption in materials. The instructor discusses the significance of Einstein coefficients in these processes and how they relate to the absorption coefficient. The lecture further explores the generation rate of electron-hole pairs in semiconductors and the differences between direct and indirect bandgap materials. The discussion includes various types of optical detectors, such as thermal detectors and photonic detectors, detailing their operational principles and applications. The lecture concludes with an overview of different semiconductor materials and their absorption spectra, emphasizing the importance of bandgap energy in determining the efficiency of optical detectors. Overall, this lecture provides a comprehensive understanding of the interactions between light and matter, essential for the study of optical detection technologies.