This lecture covers the theory and implementation of modelocking in ultrafast lasers, including active and passive modelocking techniques, frequency domain interpretation, synchronization of oscillations, and pulse propagation through media. The topics also include the concepts of beam quality, fiber coupling applications, and power fluctuations in lasers. The instructor discusses the history of laser technology, gain saturation, laser output power, and various types of lasers such as gas lasers, solid-state lasers, and semiconductor lasers.