Numerical analysis of the DKDP-based high-energy optical parametric chirped pulse amplifier for a 100  PW class laser

Abstract

An optical parametric chirped pulse amplifier (OPCPA) based on a large-aperture DKDP crystal and pumped by a 10 kJ level Nd:glass laser can serve as the final amplifier for a 100 PW level laser. A comprehensive numerical investigation on such a high-energy OPCPA is presented in this work. The effects on the efficiency–bandwidth product induced by the deuteration level, absorption loss, temperature variation, and optimization of zero-phase-mismatch wavelength (ZPMW) are analyzed in detail. Based on the analysis above, a three-dimensional numerical simulation taking into account the effects of pumping depletion, diffraction, and walk-off shows that, by optimization of ZPMW, broadband (over 210 nm spectral width in FWHM) and high efficiency ( > 37 % ) amplification can be realized in the DKDP crystal even with a moderate deuteration level of 70%, which can relax the requirement of a high deuteration level in a large-aperture DKDP crystal. The numerical analysis can provide meaningful guidance for the design and construction of 100 PW class laser systems.

eXawatt Center for Extreme Light Studies

“…[10], the dependence of the refractive index of this crystal on the wave frequency (the Sellmeier formula) was determined for an arbitrary degree of deuteration and it was found that, when pumped by the second harmonic of a neodymium laser at the central wavelength of an amplified pulse of 910 nm, ultra-wideband phase matching exists. Further studies [30,[52][53][54][55][56] confirmed these results and showed the prospectivity of using a DKDP crystal for broadband OPCPA. In combination with the ability to grow a crystal with an aperture of tens of centimeters, this provides a unique opportunity to transfer energy from a narrow-band neodymium laser pulse to a broadband chirped pulse that can be compressed down to 10-20 fs.…”

“…In the intermediate amplifier, the beam diameter is 10 cm and, in principle, a lithium triborate (LBO) crystal [ 58 ] can be used, but the gain band in it is shifted towards short wavelengths [ 5 ] . As the degree of deuteration of the DKDP crystal decreases, the center of the gain band shifts to the long wavelength region, closer to degenerate phase matching; the band width increases, but the idler wave absorption also increases [ 55 , 56 ] . For the required spectral width of 150 nm (see Section 2.6), the deuteration degree of 80% seems to be optimal.…”

Multi-layer phenomena in petawatt laser-driven acceleration of heavy ions

“…Simulated by a twodimensional (2D) particle-in-cell (PIC) code ELMIS [15], composite targets were shown be able to produce ion beams with an energy spread as low as and Fe 24+ with energy up to at laser intensities of [16]. Simulated results using a 2D PIC code KLAP2D [17,18] showed that a laser of can turn out a singleenergy Fe 24+ beam with a peak energy of [19], and 2D PIC simulations with the EPOCH code [20] showed an acceleration ability with Au up to , which has been confirmed in experiments [21].…”

“…) [21], as shown in figure 1(a). The tendencies of all Au ion energy spectra are approximately same.…”

Optimization of high peak power few-cycle optical parametric chirped pulse amplifier systems

“…Furthermore, the computational requirements are exponentially increasing in case of large beam sizes and longer than 10 ps pulse durations. However, even with 2D models, which take into account the temporal shape of the pulse and the interaction distance (t, z) [59,60] or those which neglect some features, for example dispersion [61], can provide useful information. The effectiveness of 4D models (x, y, t, z) during the design of OPCPA systems operating in the few picosecond temporal range, has been proven by many authors [62][63][64][65].…”