Applications of lock in amplifiers in optics Lock in amplifiers are key devices in several instruments used in the optical sciences or in optical equipment in the industry. In many experimental configurations they represent the means to reliably detect and record small signals. The purpose of this text is to provide a step by step introduction to this technique. The book explains how modulation is used to extract a signal from noise and describes lock in amplifier applications in optics. The book is intended for readers who want to better understand instruments and experiments based on lock in detection and or to design (and perform) new experiments in which lock in amplifiers are applied ...