Femtosecond fiber-feedback optical parametric oscillator

We demonstrate what is to our knowledge the first synchronously pumped high-gain optical parametric oscillator (OPO) with feedback through a single-mode fiber. This device generates 2.3 to 2.7W of signal power in 700 to 900-fs pulses tunable in a wavelength range from 1429 to 1473nm. The necessary high gain was obtained from a periodically poled LiTaO3 crystal pumped with as much as 8.2W of power at 1030nm from a passively mode-locked YbYAG laser with 600-fs pulse duration and a 35-MHz repetition rate. The fiber-feedback OPO setup is compact because most of the resonator feedback path consists of a standard telecom fiber. Because of the high parametric gain, the fiber-feedback OPO is highly insensitive to intracavity losses. For the same reason, the synchronization of the cavity with the pump laser is not critical, so active stabilization of the cavity length is not required

High-energy multiwatt femtosecond diode-pumped Yb:CaAlGdO4and Yb:CaF2regenerative amplifiers

We study and compare the performance of Yb:CaAlGdO4- and Yb:CaF2-based regenerative amplifiers at low (5 to 10 kHz) and high (up to 500 kHz) repetition rates. Both materials allow for pulse energies of <1 mJ with sub-400-fs at low repetition rates and up to 9.4 W of average output power at 500 kHz. Thanks to the good thermal properties of Yb:CaF2 and Yb:CALGO, the extracted energy has the potential to be significantly increased with further pump power scaling. Shorter pulses are also potentially achievable by optimizing the design of stretcher and compressor in order to better compensate higher-order dispersion and reduce nonlinear effects

Multi-kHz, High Energy, Femtosecond Diode-Pumped Yb:CaF2 Regenerative Amplifier

We report an efficient, high-energy, diode-pumped Yb:CaF2 regenerative amplifier. Energies up to 1.02 mJ at 1045-nm and 5 kHz-repetition rate in 324 fs-long pulses have been obtained with a beam quality factor of M2 =1.1

High pulse energy multiwatt Yb:CaAlGdO4 and Yb:CaF2 regenerative amplifiers

We investigated and compared Yb:CaAlGdO4 and Yb:CaF2 regenerative amplifiers at repetition rates 5-10 kHz, a frequency range interesting for industrial applications requiring relatively high pulse energy. Both materials allow for pulse energies close to 1 mJ with sub-400-fs pulses. The two laser materials offer comparable performance in the pump power range investigated. The same regenerative amplifiers can be run up to 500 kHz for much faster material processing, with maximum output power of up to 9.4 W