Passive Modelocking

Abstract

A comprehensive introduction to passive modelocking is presented, mainly based on the Haus master equation approach. There has been tremendous progress with regard to the performance frontier in passively modelocked solid-state lasers in terms of pulse duration, pulse energy, average power, and pulse reptition rates. In the introduction a short historical overview is given, with updates of the current performance frontiers in the last section. In the main part of the chapter the following techniques are introduced: coupled-cavity modelocking, passive modelocking with a slow saturable absorber and dynamic gain saturation (such as colliding pulse modelocking), passive modelocking with a fast saturable absorber (such as Kerr lens modelocking), passive modelocking with a slow saturable absorber without dynamic gain saturation (such as soliton modelocking), and dual-comb modelocking. Q-switching instabilities for passively modelocked solid-state lasers are discussed and solutions are provided with special cavity designs and negative SPM. Passively modelocked optically-pumped semiconductor and diode-pumped solid-state lasers are used to give more detailed examples. This chapter does not cover ultrafast fiber lasers.