ChirpedPulseOscillators:Generatingmicrojoulefemtosecondpulsesatmegahertzrepetitionrate´ ´AlmaFernandezGonzalezMunchen¨ 2007ChirpedPulseOscillators:Generatingmicrojoulefemtosecondpulsesatmegahertzrepetitionrate´ ´AlmaFernandezGonzalezDissertationanderFakultat¨ fur¨ PhysikderLudwig–Maximilians–Universitat¨Munchen¨vorgelegtvonAlmaFernandez´ Gonzalez´ausPenonome,´ Cocle,´ Panama´Munchen,¨ den27.Februar2007Erstgutachter:Prof.Dr.FerencKrauszZweitgutachter:Prof.Dr.HaraldWeinfurterTagdermundlichen¨ Prufung:¨ 31.Mai2007vtomymotherandmyfatherviAbstractThe maximum energy achievable directly from conventional Ti:sapphire oscillators has beenlimited by the onset of instabilities such as cw generation and pulse splitting because of thehigh intensity in the laser medium. Generation of microjoule pulses at megahertz repetitionratesareofspecialinterestinmanyareasofscienceandtechnology.The main subject of this thesis is the development of high energy Ti:sapphire oscillatorsat megahertz repetition rate. The main concept that was applied to overcome the difficultiespointed out above was to operate the laser in the positive dispersion regime. By operatingthe laser in this regime, intracavity picosecond pulses are generated that can be externallycompressed down to femtosecond pulse durations. The long pulse duration inside the laseroffers an elegant way to reduce pulse instabilities by decreasing the intracavity intensity viapulse stretching.