title: High-power top-hat pulses from a Yb master oscillator power amplifier for efficient optical parametric amplifier pumping.
abstract: We demonstrate shaping of high-energy broadband Yb amplifier pulses for the generation of a (sub)picosecond top-hat temporal pulse profile that significantly improves pumping efficiency of an optical parametric amplifier (OPA). Phase-only modulation is applied by an acousto-optic programmable dispersion filter. This simple scheme is scalable to a high average power due to a relatively broad bandwidth of the Yb:CaF(2) gain medium used in the amplifier that supports a sub-150-fs transform-limited pulse duration. Additionally we show that OPA seeding with supercontinuum remains possible because top-hat-shaped pulses passed through a glass block recompress to ≈200 fs with minimum satellite production.
authors: Photonics Institute, Vienna University of Technology, Gusshausstrasse 27/387, A-1040 Vienna, Austria. tadas.balciunas@tuwien.ac.at
authors: T
authors: T
authors: Balčiūnas
authors: G Y
authors: GY
authors: Fan
authors: G
authors: G
authors: Andriukaitis
authors: A
authors: A
authors: Pugžlys
authors: A
authors: A
authors: Baltuška
mesh_terms: D053844:Lasers, Solid-State; D055620:Optical Phenomena; D013057:Spectrum Analysis; D015018:Ytterbium
chemical_list: D015018:Ytterbium