title: Ultra-high contrast frontend for high peak power fs-lasers at 1030 nm.
abstract: We present the results from a new frontend within a double-chirped pulse amplification architecture (DCPA) utilizing crossed-polarized wave generation (XPW) for generating ultra-high contrast, 150 μJ-level, femtosecond seed pulses at 1030 nm. These pulses are used in the high energy class diode-pumped laser system Polaris at the Helmholtz Institute in Jena. Within this frontend, laser pulses from a 75 MHz oscillator-pulse train are extracted at a repetition rate of 1 Hz, temporally stretched, amplified and then recompressed reaching a pulse energy of 2 mJ, a bandwidth of 12 nm and 112 fs pulse duration at a center wavelength of 1030 nm. These pulses are temporally filtered via XPW in a holographic-cut BaF₂ crystal, resulting in 150 μJ pulse energy with an efficiency of 13 %. Due to this non-linear filtering, the relative intensity of the amplified spontaneous emission preceding the main pulse is suppressed to 2×10⁻¹³. This is, to the best of our knowledge, the lowest value achieved in a high peak power laser system operating at 1030 nm center wavelength.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Liebetrau
authors.forename: Marco
authors.initials: M
authors.lastname: Hornung
authors.forename: Andreas
authors.initials: A
authors.lastname: Seidel
authors.forename: Marco
authors.initials: M
authors.lastname: Hellwing
authors.forename: Alexander
authors.initials: A
authors.lastname: Kessler
authors.forename: Sebastian
authors.initials: S
authors.lastname: Keppler
authors.forename: Frank
authors.initials: F
authors.lastname: Schorcht
authors.forename: Joachim
authors.initials: J
authors.lastname: Hein
authors.forename: Malte C
authors.initials: MC
authors.lastname: Kaluza