title: The generation of amplified spontaneous emission in high-power CPA laser systems.
abstract: An analytical model is presented describing the temporal intensity contrast determined by amplified spontaneous emission in high-intensity laser systems which are based on the principle of chirped pulse amplification. The model describes both the generation and the amplification of the amplified spontaneous emission for each type of laser amplifier. This model is applied to different solid state laser materials which can support the amplification of pulse durations ≤350 fs . The results are compared to intensity and fluence thresholds, e.g. determined by damage thresholds of a certain target material to be used in high-intensity applications. This allows determining if additional means for contrast improvement, e.g. plasma mirrors, are required for a certain type of laser system and application. Using this model, the requirements for an optimized high-contrast front-end design are derived regarding the necessary contrast improvement and the amplified "clean" output energy for a desired focussed peak intensity. Finally, the model is compared to measurements at three different high-intensity laser systems based on Ti:Sapphire and Yb:glass. These measurements show an excellent agreement with the model.
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Keppler
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Sävert
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Körner
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany; Helmholtz-Institute Jena Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Hornung
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Liebetrau
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany; Helmholtz-Institute Jena Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Hein
authors.affiliation: Institute of Optics and Quantum Electronics Friedrich-Schiller-University of Jena Germany; Helmholtz-Institute Jena Germany.
authors.forename: Malte Christoph
authors.initials: MC
authors.lastname: Kaluza
keywords: ASE; Amplified spontaneous emission; CPA; high power lasers; laser amplifiers; laser plasma interaction; modelling; regenerative amplifier; temporal intensity contrast