28-W, 217 fs solid-state Yb:CAlGdO4 regenerative amplifiers

A new high-performance Yb:CaAlGdO4 (Yb:CALGO) regenerative amplifier is demonstrated. Pumped by 116 W at approximate to 980 nm and seeded by means of a 92 fs oscillator, it generates as much as 36 W of average output power with chirped pulses, and 28 W with 217 fs compressed pulses at 500 kHz repetition rate. This corresponds to 56 mu J of pulse energy and 258 MW peak power. The compressed pulses have a time-bandwidth product of 0.69 and could be shortened further with an improved compressor setup. (C) 2013 Optical Society of America