Lecture
This lecture covers various optical detection methods, focusing on synchronous and direct detection techniques. It begins with time-of-flight measurements, illustrating how LED and photodiodes can be used for distance measurement. The instructor presents examples of photon counters and their applications in 1D and 3D imaging, highlighting a commercial product from Bosch. The lecture then delves into direct detection, explaining the principles and components involved, such as signal processing with ADC cards and Labview interfaces. Synchronous detection is introduced next, detailing its spectral analysis through sinusoidal modulation. The instructor discusses the use of lock-in amplifiers and choppers, providing examples of equipment from Stanford Research Systems. The lecture also draws parallels between synchronous detection in optics and AM radio techniques, emphasizing the importance of phase checking. Finally, the concepts of heterodyne detection and interferometry are explored, showcasing their relevance in optical coherence tomography and the significance of coherence length in different light sources.