Studies On Femtosecond Pulses Shaping

With the rapid development of femtosecond optics, it is possible for ultrashortoptical pulses of 1~2-cycle pulses, and it has been used as an important tool for the process of ultrafast dynamics and phenomenon. The laser pulse from the high power ultrashort laser system is several femtoseconds in the duration, TW (or PW) level in the peak power, 1020W/cm2 (or 102IW/cm2) in focusing power density, which electric field is much stronger than coulomb field in atoms. It introduces extreme physical conditions such as high temporal resolving power, strong electromagnetic field and high pressure, and thus results in a comprehensive and profound revolution in fundamental and technology science. Recently, optical pulse shaping has been focused for their applications on the coherent quantum control and it attracts more attentions all over the world.In this thesis, the author has mainly focused on femtosecond pulse shaping technology. It includes:1. The development of the pulse shaping was summarizes. The passive pulse shaping technology, such as grating pairs, prisms pairs, chirped pairs and their combination, was introduced, and the active pulse shaping technology, such as MMDM(Micromachined Deformable Mirror), AOPDF (Acousto-Optic Programmable Dispersive Filter) and SLM (Spatial Light Modulator) was presented.2. The pulse shaping setup with the feedback loop was established. The 4f type pulse shaping system was built, the temporal aberrations induced by the mismatches of the 4f Fourier processing system were calculated and discussed, and the software for the feedback loop control system of femtosecond pulse shaping, based on Genetic Arithmatics, was made by Lab view and C.3. Second harmonic generation (SHG) of BBO crystal was coherentlyenhanced by using the pulse shaping system with the feedback loop control, the laser pulse parameters were measured by the SPIDER technology, and the coherently enhanced mechanisms for SHG were discussed and analysed. In conclusion, the above provides instructive guide for future researches on coherent quantum control.