Optical Detection: Position-Sensitive Detectors and Applications

This lecture presents selected examples of optical methods, focusing on position-sensitive detectors. The instructor explains the functionality of two-dimensional position-sensitive devices, including quad cells and photodiodes, which detect the position of light spots. Applications such as the Cavendish pendulum and Atomic Force Microscopy (AFM) are discussed, illustrating how these detectors measure movements and distances. The lecture also covers telemetry and autofocus systems in cameras, detailing how position-sensitive detectors help achieve proper focus by analyzing light spots. The instructor describes the mechanics of reflex cameras and the process of capturing three-dimensional images using dual cameras and specialized screens. Techniques for structured light illumination are introduced, demonstrating how to capture the three-dimensional profile of objects. The lecture concludes with an example of a virtual keyboard using projected light and infrared detection, showcasing the versatility of optical detection methods in various applications.