title: 110-mJ 225-fs cryogenically cooled Yb:CaF2multipass amplifier.
abstract: We report on a diode-pumped cryogenically cooled bulk Yb:CaF212-pass amplifier delivering 110-mJ, 1030-nm pulses at a 50-Hz repetition rate. The pulses have a spectral bandwidth of 13 nm and are compressed to 225 fs pulse duration in a double reflection grating based compressor having a transmission efficiency of >90%. The measured output beam quality is M2<1.1. A key feature of the amplifier design is the 4f relay imaging onto the gain medium with progressive beam magnification for the mitigation of the spatial gain narrowing effect. The number of passes in the amplifier is scalable by increasing the size of imaging mirrors. In order to prevent accumulation of nonlinear phase due to self-phase modulation in air, the amplifier is enclosed into a low-vacuum case.
authors.forename: E
authors.initials: E
authors.lastname: Kaksis
authors.forename: G
authors.initials: G
authors.lastname: Almási
authors.forename: J A
authors.initials: JA
authors.lastname: Fülöp
authors.forename: A
authors.initials: A
authors.lastname: Pugžlys
authors.forename: A
authors.initials: A
authors.lastname: Baltuška
authors.forename: G
authors.initials: G
authors.lastname: Andriukaitis