Chapter 5 Regular Q-switching mode locking: Combination of nonlinear mirror and semiconductor saturable absorber mirror

5-1 Motivation Since we demand high peak power and low repetition rate output in Nd:GdVO4 laser using nonlinear mirror absorber and SESAM, in this chapter, the experiment setup is slightly different from the previous ones in Chapters 3 and 4. In order to prevent damage of SESAM at high intra-cavity peak power, SESAM (the same as Chapter 2) is inserted at the position where has a larger radius of ~ 400 μm, estimated in use of the ABCD law. The idea of dual mode locking is that the SESAM plays the role of Q-switching due to large spot size and nonlinear mirror plays the role of mode-locking. Therefore, the dynamics of the pulses and the ranges of the ML state as the position of KTP insertion were investigated in our dual mode locking laser.