Multi-mJ, 200-fs, cw-pumped, cryogenically cooled, Yb,Na:CaF_2 amplifier

Abstract

Using a novel (to our knowledge) broadband Yb-doped Yb3+,Na+:CaF2 crystal cooled in a closed loop to 130 K we demonstrate a chirped pulse regenerative laser amplifier delivering the energy of up to 3 mJ at a repetition rate of 1 kHz and an average output power of 6 W at 20 kHz. The gain narrowing in the laser crystal is compensated by shaping the amplitude of the seed pulse spectrum. As the result, at the highest amplified pulse energy we obtain a 12 nm FWHM bandwidth supporting a 130 fs pulse duration, assuming ideal compression. Amplified pulses were recompressed from 250 ps to 195 fs with a 1700 lines/mm transmission grating compressor.

110-mJ 225-fs cryogenically cooled Yb:CaF_2 multipass amplifier

“…At full pump load of 200 W the temperature of the crystal rises to 55 K. Yb:CaF2 crystal was aligned in such a way that the laser beam was propagating along [111] direction. The amplifier is seeded by the output of a cryogenically cooled Yb:CaF 2 chirped pulse regenerative amplifier [28], which generates 12 mJ, 500 ps pulses with the spectrum supporting sub-200 fs pulse duration.…”

Ultrafast Laser Oscillators and Amplifiers

“…These approaches combine high average powers with low nonlinearities. The latest developments are documented in [105,106]. The regenerative amplifier is the traditional amplification scheme for directly diode-pumped low gain materials such as Yb-based crystals since the number of passes through the gain medium is flexible.…”

Optical studies of samarium-doped fluoride nanoparticles

“…Among the alkali fluoride compounds, CaF 2 is an attractive material because of its high stability and non-hygroscopic behavior. Recently, CaF 2 has attracted renewed interest as a laser material when doped with rare earths [9,10]. CaF 2 nanoparticles have been synthesized by different methods, such as the sol-gel method [11][12][13][14][15][16], solvothermal process [17,18], reverse micelle method [19,20], hydrothermal method [21], different precipitation methods [22][23][24], flame synthesis [25], etc.…”