Generation, amplification and characterization of ultrashort laser pulses generated by titanium-doped sapphire

My research is one of the pioneering works on the understanding of the generation of ultrashort laser pulses and the developing of the new generation of ultrashort high power laser systems. It results in the new technology that improves the performance of ultrashort laser systems to the next level. There are two main parts in this thesis, generation of ultrashort laser pulses directly from a laser oscillator and amplification of the ultrashort laser pulses to terra watt (TW) level.; A numerical calculation was performed to characterize the dispersion of a Titanium doped sapphire (Ti:sapphire) laser. By optimizing the dispersion compensation, I was able to design and construct three Ti:sapphire lasers each of which generates record breaking ultrashort optical pulses, whose durations are 25 fs, 17 fs and 11 fs respectively. The optimization methods include: choosing the proper prism material for dispersion compensation, reducing the dispersion in the laser cavity and using commercial multilayer mirrors with special dispersion characteristics for dispersion compensation. In addition, this work and other collaboration works contribute much of the knowledge about the mechanism responsible for the self-modelocking which enables the generation of ultrashort laser pulses in a Ti:sapphire laser.; By applying the technique developed for the ultrashort laser cavity to a Ti:sapphire amplifier, the performance of the amplifier system can be dramatically improved. A multipass, low dispersion amplifier was designed using this new technique. Combined with the matching stretcher and compressor designs, this amplifier system can generate pulses as short as 26 fs with peak power over 2 TW at 10 Hz. These are the shortest terra watt optical pulses to the best of my knowledge. In the last chapter, a new technique for determining the phase and temporal shape of an amplified pulse using self phase modulation was tested. The results agreed very well with the experimental data. This new technique can be a useful diagnostic tool for monitoring the performance of an amplifier system.