Abstract

The direct generation of high energy pulses with a diode-pumped solid-state laser oscillator is a promising approach to enable the multi-megahertz operation of numerous applications in science and industry. Thin disk lasers enable the required average power with excellent beam quality, such that passive mode locking with a semiconductor saturable absorber mirror (SESAM) can be achieved. Using this concept, we have recently been able to reach a pulse energy as high as 5.1 μJ at 12 MHz repetition rate from an Yb:YAG thin disk oscillator [1]. This significant increase over previous results was made possible by realizing the importance of the nonlinearity of air inside a thin disk laser cavity. To eliminate the air’s contribution to the nonlinearity, we covered the laser with a box which then was flooded with helium.

© 2007 IEEE