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We present an Yb-CALGO thin-disk laser in continuous regime. In a slightly multimode configuration we obtain up to 29.5W of average power, corresponding to a slope efficiency of 40% and an optical-to-optical efficiency of 32%. We then design a monomode cavity, and achieve 25W of average power. The tuning range of the laser emission was from 1018 to 1052nm. In a Q-switch regime, we obtain more than 1 mJ at 100 Hz repetition rate, and 4.5W at 10 kHz repetition rate.

Cryogenic cooling is a very interesting and promising apparatus for high power lasers, especially with Yb-doped materials. In fact, it is now well known that operating this type of laser materials at cryogenic temperatures such as 77K (liquid nitrogen temperature) positively affects their performance, especially at high power levels, because of increased thermal conductivities and absorption and emission cross sections. We present a high-power diode-pumped Yb:CaF2laser operating at cryogenic temperature (77 K). A laser output power of 97 W at 1034 nm was extracted for a pump power of 245 W. The corresponding global extraction efficiency (versus absorbed pump power) is 65%. The laser small signal gain was found equal to 3.1. The laser wavelength could be tuned between 990 and 1052 nm with peaks which well correspond to the structure of the gain cross section spectra registered at low temperature.

Many industrial and scientific applications need ultra-short and energetic pulses. Diode-pumped systems based on ytterbium-doped crystals have a huge interest thanks to their good thermal and spectroscopic properties. Among them, Yb:CaF2, shows very promising results for short pulse generation, and its long fluorescence lifetime, 2.4 ms, indicates a high energy storage capacity. We present a diode-pumped regenerative amplifier based on an Yb:CaF2crystal optimized to produce short pulses for various repetition rates ranging from 100 Hz to 10 kHz. The experiment is performed with a 2.6-% Yb doped 5-mm-long CaF2crystal grown by using the Bridgman technique and used at Brewster angle. To optimize the injection pulse spectrum in terms of bandwidth and maximum gain, the seed pulses are generated by a broadband Yb:CALGO oscillator centered at 1043 nm with a FWHM bandwidth of 15 nm at a repetition rate of 27 MHz. The pulses are then stretched to 260 ps with a transmission grating. The shortest pulse duration generated is 178-fs, and the corresponding energy is 1.4 mJ before compression (620 J after), at a repetition rate of 500 Hz for 16 W of pump power. The bandwidth is 10 nm centered at 1040 nm. At 10 kHz repetition rate, 1.4 W of average power before compression is obtained, corresponding to an optical-optical efficiency of 10%. We also noticed that the pulse duration tends to increase above 1 kHz, reaching 400 fs at 10 kHz.