1. Laser apparatus, comprising:a fiber-laser oscillator delivering optical pulses having a first pulse-duration, the pulses having a center-wavelength between 1038 nanometers and 1052 nanometers;
a pulse-stretcher arranged to stretch the duration of the optical pulses to a second pulse-duration longer than the first pulse-duration;
at least one fiber-amplifier arranged to amplify the stretched optical pulses;
a solid-state multi-pass amplifier including a gain-element made of ytterbium-doped yttrium aluminum garnet having a peak-gain wavelength of about 1030 nm, arranged to further amplify the amplified stretched optical pulses from the fiber-amplifier; and
a pulse-compressor arranged to reduce the duration of the further-amplified optical pulses from the solid-state multi-pass amplifier to a duration of less than about 400 femtoseconds.