Studies Of The Technologies In Femtosecond, High-intensity Laser System

With the advent of the chirped-pulse amplification (CPA) technique, rapid progress has been made in the development of ultrahigh and ultrafast laser systems. CPA has made a promising way for damage-free amplification of short pulses to terawatt levels and beyond. Using large gain bandwidth materials such as Ti:sapphire permits the amplification of femtosecond pulses, and Ti:sapphire amplifiers can produce ultrahigh peak-power, ultrashort pulses, which are useful for a variety of high-field applications such as the generation of ultrafast X-ray radiation, high-order harmonic generation and so on.In this paper, the technologies in high-intensity ultrafast pulse laser system arc studied. A 5-TW/40-fs table-top Ti:sapphire laser system was built and can work with stability. We expect the laser system is becoming primary source for the research on phenomena in strong-field physics regime. The main research has been summarized as follows.First, A 5-TW/40-fs table-top Ti:sapphire laser system was built. We present the design and performance of an efficient, femtosecond, high-intensity Ti:sapphire laser system, based on TSA-25 regeneration amplifier, with two-stage amplifier including 10×10×15mm and Φ15×15mm Ti:sapphire crystals, pumped by 0.6J and 1.6J 532nm/10Hz of Nd:YAG lasers. Compared with the different absorption of crystals for 532nm, pump-to-IR efficiency with pump fluence and passes of amplification, the system output energy achieved 500mJ. Using a single grating compressor, a pulse with duration of less than 41fs can be generated, the transmission of energy was 63% and the highest peak power can reach 7.6TW. The power amplifier of our Ti:sapphire laser system which is pumped by Nd:YAG laser can achieve extraction efficiency that approach~34%. In our opinion, this laser system is characteristic of high flexibility, safety, working stability, economy, and so on.Second, Some key techniques related to 5-TW/40-fs laser system were developed, for example, the choice of different gain mediums, the multiple choices of the amplified passes, the distribution of extraction energy with high energy extractingefficiency, etc. The generation of the femtosecond laser pulse was studied; the modulation of this system was learned. We succeed in the design of varied kinds of optic components in high-intensity and femtosecond laser system.Third, Developed of a technique for the precisely timing synchronization of the pump and signal pulse; mastery of new technology, such as the types of the measurement for femtosecond laser pulse, the interferometric autocorrelation and the beam propagation analyzer M~2-200 were learned. In addition, the key problems, for example, thermal-lensing effect and amplified spontaneous emission (ASE) are systematically summarized.