Mode Locking Techniques: Generating High Power Lasers

This lecture covers the principles of mode locking in lasers, focusing on techniques to generate high peak power. It begins with a recap of beam steering and diffraction-based steering, explaining how the diffraction angle can be manipulated through various parameters. The instructor discusses the motivation behind achieving a laser power of 1 MW, emphasizing the importance of pulse duration and peak power. The relationship between average power, pulse energy, and pulse duration is established, highlighting the significance of short pulses in laser applications. The lecture delves into the basics of pulse characteristics, including the time and spectral domain relationships, and introduces the concept of transform-limited pulses. The instructor explains the statistical definitions of pulse width and the implications of different pulse shapes. The discussion progresses to active mode locking, detailing how modulation techniques can synchronize multiple longitudinal modes within a laser cavity. The lecture concludes with practical implementations of these concepts, including the use of acoustic modulators for effective mode locking.