Broadband Ultrashort Pulse Laser Amplifier

This thesis yresents detailed theoretical and experimental studies on broadband ultra-short pulse amplification. The main achievements are summarized as follows: 1. The history of ultra-short laser pulse generation and amplification are reviewed and the latest development of CPA techniques are also briefly introduced. 2. Numerical calculation on the multi-pass amplification of optical pulses are conducted. Important relationship between the input pulse and output pulse parameters are revealed by detailed calculation and analysis. Discussions about the pulse fluence, gain and pass-number result in a useful guideline for further experimental studies on regenerative & multi-pass amplifiers. 3. Based upon the theoretical model of ultra-short pulse propagation and amplification in gain medium, nonlinear effects such as gain narrowing, saturation and SPM effects in the process of pulse amplification are studied theoretically and numerically. In particular, analysis and suggestion are put forward to suppress these unexpected effects. 4. The experimental research on Ti:sapphire regenerative and multi-pass amplifiers has been carried out with overall gain exceeding i07. 2OmJ amplified output energy was obtained, yielding 20% amplification conversion efficiency. Practical adjustment techniques are also included. 5. A high-gain Nd:glass regenerative amplifier was constructed and tested with subsequent pre-amplifiers, providing a front-end with appreciable energy for high- energy short-pulse glass-laser facility working around 1 micron. As much as I O20mJ energy and over iO gain were produced. Several important issues in connection with glass CPA lasers are investigated and discussed. 6. We numerically solved the nonlinear 3-wave coupled equations to have a full view on the optical parametric amplification process. Simulations on the OPA characteristics show that it is possible to achieve both high-energy and extremely short-pulse with the existing nonlinear medium and conventional pump sources. This work laid the foundation for further study and development of new ultra-intense ultra- short pulse laser facilities.