Compact laser-diode-based femtosecond sources

This paper describes the development of compact femtosecond laser systems that are capable of being directly pumped by laser diodes or are based directly on laser diodes. The paper demonstrates the latest results in a highly efficient vibronic based gain medium and a diode-pumped Yb:KYW laser is reported that has a wall plug efficiency > 14%. A Cr⁴⁺:YAG oscillator is described that generates transform-limited pulses of 81 fs duration at a pulse repetition frequency of > 4 GHz. The development of Cr³⁺:LiSAF lasers that can be operated using power supplies based on batteries is briefly discussed. We also present a summary of work being carried out on the generation of fs-pulses from laser diodes and discuss the important issues in this area. Finally, we outline results obtained on the generation of pulses as short as 550 fs directly from a two-section quantum dot laser without any external pulse compression.