PEARL laser complex
The femtosecond laser complex PEARL was created at IAP RAS (A. K. Potemkin, V. V. Lozhkarev, A. A. Shaikin, E. V. Katin, I. V. Yakovlev, V. N. Ginzburg) under the leadership of E. A. Khazanov in 2006. It is based on parametric amplification of laser pulses, as well as on amplification of prestretched chirped pulses that is a traditional principle used for generation of ultraintense magnetic fields. At the output, the pulse is compressed to the initial duration.
The IAP RAS researchers were the first to formulate, develop and test in experiments the OPCPA concept in the conditions of ultrabroadband synchronism in DKDP crystals (deuterated potassium dihydrogen phosphate) which demonstrated that the decay of a quantum of a pump wave at the wavelength of 527 nm into a quantum of a signal wave (910 nm) and a quantum of an idler wave (1250 nm) is the principal elementary quantum process in the amplification scheme. This scheme is now recognized worldwide as the most promising for mastering new frontiers of laser radiation power and intensity.
The PEARL complex architecture is based on the original OPCPA scheme that allows obtaining a total energy gain over 1010 in three crystals only. In the first parametric amplifier (a 120 mm long DKDP crystal with a deuteration degree of about 90%) not only broadband amplification is accomplished, but also chirped pulses at the wavelength of 1250 nm are converted to signal pulses at the wavelength of 910 nm. In the second crystal with analogous characteristics, parametric amplification with saturation up to an energy of 100 mJ occurs, which corresponds to the terawatt power level. In the third DKDP crystal with a length of 80 mm and clear aperture of 110 mm, the chirped pulse energy amounts to 38 J with maximum efficiency of the parametric amplifier of 23%.
This amplifier is pumped by a specially designed compact Nd-glass rod laser with pulse duration of 1.2 ns and energy in the second harmonic up to 180 J. The pulse is compressed by a vacuum compressor with two diffraction gratings and overall transmission coefficient of 65%. The maximum attained energy of the compressed pulses was 24 J with duration of 43 fs and spatial beam quality close to the diffraction limit, which corresponds to the peak power of 0.56 PW and the possibility of focusing the radiation to the intensity of 1022 W/cm2.