Terawatt diode-pumped Yb:CaF_2 laser

Abstract

We present what we believe to be the first terawatt diode-pumped laser employing single-crystalline Yb:CaF(2) as the amplifying medium. A maximum pulse energy of 420 mJ at a repetition rate of 1 Hz was achieved by seeding with a stretched femtosecond pulse 2 ns in duration, preamplified to 40 mJ. After recompression, a pulse energy of 197 mJ and a duration of 192 fs were obtained, corresponding to a peak power of 1 TW. Furthermore, nanosecond pulses containing an energy of up to 905 mJ were generated without optical damage.

Diode-pumped Yb:CaF $$_2$$ 2 multipass amplifier producing 50 mJ with dynamic analysis for high repetition rate operation

“…The measured spectrum remains also identical (3.1 nm FWHM, FTL 500 fs) to the injected one (Fig. 10) showing the interest to use Yb:CaF2 gain medium to avoid any gain narrowing [5,[13][14][15]. 6 Conclusion To summarize, the exact measurement of the thermal lens allows us to optimize the design of the Yb:CaF2 amplifier avoiding beam focusing and then to extract efficiently and reliably the energy without damaging the optics and access safely to a reliable stable regime within a 50-mJ range.…”

“…For these large-scale installations, cost-efficient solutions are preferred. Efficient diode pumping usually involves ytterbium-doped materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The development of the technology is mainly based on the knowledge of the amplifying material.…”

“…It possesses a longfluorescence lifetime, 2.4 ms, which facilitates the storage of energy [4]. Also, the large bandwidth of this material makes it an attractive candidate for the generation and amplification of ultrashort pulses [5,11,12,15,[17][18][19]. The material also sustains high average power thanks to its good thermal conductivity, 6 Wm_1 K_1 (for a typical doping of 2%) [13,14,20].…”

The all-diode-pumped laser system POLARIS – an experimentalist’s tool generating ultra-high contrast pulses with high energy

“…The amplified pulses can then either be sent to the main compressor or used as a seed for the final amplifier A5. This amplifier uses Yb:CaF 2 in a nine-pass configuration as the active material [23][24][25] and is currently able to deliver a maximum output energy of 16.6 J (with 2.7 J seed energy). The active material of this amplifier is pumped by 120 laser diode stacks in a 2.5 ms long pump pulse at 940 nm with a 300 kW pump power.…”

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

“…A number of regenerative and multipass Yb:CaF 2 amplifier designs have been reported with the parameters peaking at 16.6 J pulse energy at sub-Hz repetition rate [25] and 160 mJ pulse energy at 20 Hz repetition rate [26] in the case of uncompressed ns pulses and reaching 420 mJ energy for compressed femtosecond pulses at 1 Hz repetition rate [27].…”