Abstract:We report on a 2.0 PW femtosecond laser system at 800 nm based on the scheme of chirped pulse amplification using Ti:sapphire crystals, which is the highest peak power ever achieved from a femtosecond laser system. Combining the index-matching cladding technique and the precise control of the time delay between the input seed pulse and pump pulses, the parasitic lasing in the final booster amplifier is effectively suppressed at the pump energy of 140 J at 527 nm. The maximum output energy from the final amplifier is 72.6 J, corresponding to a conversion efficiency of 47.2% from the pump energy to the output laser energy. The measured spectral width of the amplified output pulse from the final amplifier is 60.8 nm for the full width at half-maximum (FWHM) by controlling the spectral evolution in the amplifier chain, and the recompressed pulse duration is 26.0 fs. The technology of cross-polarized wave (XPW) is applied in a broadband front-end, and the pulse contrast is improved to ~1.5 × 10 −11 (−100 ps before the main pulse) which is measured at 83 TW power level with a repetition rate of 5 HZ. , 963-965 (1999). 13. F. Ple, M. Pittman, G. Jamelot, and J.-P. Chambaret, "Design and demonstration of a high-energy booster amplifier for a high-repetition rate petawatt class laser system," Opt. Lett. 32(3), 238-240 (2007). 14. V. Chvykov and K. Krushelnick, "Large aperture multi-pass amplifiers for high peak power lasers," Opt.Commun. 285(8), 2134-2136 (2012). 15. http://www.cargille.com. 16. D. C. Brown, S. D. Jacobs, and N. Nee, "Parasitic oscillations, absorption, stored energy density and heat density in active-mirror and disk amplifiers," Appl. Opt. 17(2), 211-224 (1978). 17. Y. Xu, X. Guo, X. Zou, Y. Li, X. Lu, C. Wang, Y. Liu, X. Liang, Y. Leng, R. Li, and Z. Xu, "Pulse temporal quality improvement in a petawatt Ti:sapphire laser based on cross-polarized wave generation," Opt.

We report on the generation of 192.3 J centered at 800 nm wavelength from a chirped-pulse amplification (CPA) Ti:sapphire laser system. The experimental results demonstrate that parasitic lasing can be suppressed successfully in the final amplifier based on a Ti:sapphire crystal of 150 mm in diameter. An over 50% pump-to-signal conversion efficiency was measured for the final amplifier by optimizing the time delay of two pump pulses and enhancing the injected seed energy. With 72% compressor throughput efficiency and 27 fs long compressed pulse duration obtained at a lower energy level, this laser could potentially support a compressed laser pulse of 5.13 PW peak power. The experimental results represent notable progress regarding the CPA laser.

In this Letter, we present a study of high-energy and high-conversion-efficiency broadband optical parametric chirped-pulse amplification (OPCPA) system with a 100  mm×100  mm×17  mm LBO crystal near 800 nm. The results showed that the back-conversion was sensitively affected by the pump intensity and the injected signal intensity. It occurred when the injected signal was above 0.82 J with a pump energy of 170 J, and this effect also reshaped the amplified spectrum. After optimization, an amplified energy of 45.3 J was achieved with a conversion efficiency of 26.3% by the OPCPA. The peak power of the hybrid CPA-OPCPA laser system reached 1.02 PW with a compressed duration of 32 fs, which is the first reported OPCPA peak power higher than 1 PW, to the best of our knowledge.

The optical parametric-chirped pulse amplification (OPCPA) based on large-aperture nonlinear optical crystals is promising for implementation of an ultrahigh peak-power laser system of 10 PW and beyond. We demonstrated the highest energy broadband OPCPA at 800 nm, to the best of our knowledge, by using an 80 mm in diameter LiB(3)O(5)(LBO) amplifier, with an output energy of 28.68 J, a bandwidth of 80 nm (FWHM), and conversion efficiency of 25.38%. After compression, a peak power of 0.61 PW with 33.8 fs pulse duration is produced.

Theoretical and experimental investigations are carried out to determine the influence of the time delay between the input seed pulse and pump pulses on transverse parasitic lasing in a Ti:sapphire amplifier with a diameter of 80 mm, which is clad by a refractive index-matched liquid doped with an absorber. When the time delay is optimized, a maximum output energy of 50.8 J is achieved at a pump energy of 105 J, which corresponds to a conversion efficiency of 47.5%. Based on the existing compressor, the laser system achieves a peak power of 1.26 PW with a 29.0 fs pulse duration.